Sports Nutrition

by Jack Norris, Registered Dietitian

Contents

• Introduction
• Protein
• Endurance
• Exercise recovery
• Iron
• Energy and fiber
• Bone stress injuries
• Creatine
• Carnitine
• Carnosine and beta-alanine
• Taurine
• Collagen
• Citations
• Excluded research

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Note: I used AI for the literature review, data analysis, claim verification, and editing of much of this article.

This article aims to include research only if it meets a minimum evidentiary bar, which varies by study type: observational studies must be prospective, and trials must report the outcome they registered in advance. Findings also need a meaningful effect size, and meta-analyses must pool enough studies with consistent results. Studies we considered but left out are listed in the Excluded Research section, with the reason. Full criteria.

Introduction

This article covers what’s different for vegan athletes; for the nutrients all vegans should pay attention to, see Nutrition Tips for Vegans.

Protein

The Institute of Medicine, which sets the RDAs, doesn’t recommend higher protein intakes for athletes. However, in a 2016 joint position paper on nutrition and athletic performance, the American College of Sports Medicine (ACSM), the Academy of Nutrition and Dietetics (AND), and Dietitians of Canada recommend higher protein intakes for athletes, in the range of 1.2 to 2.0 g/kg of body weight per day (Thomas, 2016). A meta-analysis of 82 randomized controlled trials found that, when combined with resistance training, muscle strength gains increase with total protein intake up to about 1.5 g/kg/day, with no additional benefit above that amount (Tagawa, 2022).

In the studies in Table 1, vegans and omnivores eating similar amounts of protein had similar muscle and strength outcomes. Table 2 suggests that vegans can build muscle or maintain strength at about 1 g/kg/day of protein, but that muscle was lost when a self-selected vegan diet dropped intake to about 0.76 g/kg/day. The evidence is thin, though. Few studies exist; most are small or short, and most involve beginners. We don’t know how much protein experienced vegan lifters need to keep gaining.

Table 1. Training on plant-based vs. omnivore diets

Study	Vegan protein (g/kg)	Omnivore protein (g/kg)	Population	Habitual diet	Duration	Result
Hevia-Larraín, 2021	1.6	1.6	Untrained	Vegan vs. omnivore	12 wks	No difference in mass or strength
Durkalec-Michalski, 2022	1.56	1.60	Trained	Omnivore, randomized to stay or switch	4 wks	No difference in strength
Monteyne, 2023	~2.1	~2.3	Moderately trained	Omnivore (except for 2 vegans in the vegan group), randomized to stay or switch	10 wks	Entire group gained muscle mass and strength, with no consistent differences between diets.

Table 2. Plant-protein and training results

Study	Protein (g/kg)	Population	Habitual diet	Duration	Result
Domić, 2026	~0.76 (dropped from ~1.0, unguided)	Older adults, untrained	Omnivore	12 wks	Lost muscle mass
Martini, 2026	~1.0	Untrained women	Vegan	16 wks	Gained muscle mass
Hevia-Larraín, 2021	1.6	Untrained	Vegan	12 wks	Gained muscle mass
Isenmann, 2023	~1.1	Trained lifters, 6+ mo prior	Omnivore	8 wks	Maintained strength
Durkalec-Michalski, 2022	~1.56	Trained (HIFT, 1+ yr)	Omnivore	4 wks	Maintained strength

Legumes, soy foods, quinoa, and wheat gluten (seitan) are among the highest-protein vegan foods. Vegans can also take a protein supplement, including soy-free options for those allergic to soy or who don’t want more soy in their diet.

Because it is so high in protein per serving, seitan has more of most essential amino acids than most legumes. This includes lysine, which seitan has more of than any legume except tempeh and firm tofu. The exception is tryptophan, which hasn’t been reported for seitan, so its content is unknown.

For a list of high-protein plant foods and their amino acid contents, see Protein and Amino Acid Content of Selected Plant Foods. For a more thorough discussion, see our article Protein.

Exercise scientist and bodybuilder Mike Israetel tried eating vegan for a day and reached 296 g of protein. That’s far more than most people need, but it shows how much protein a vegan diet can provide.

Endurance

We found no randomized trials comparing endurance in people assigned to a vegan diet with people assigned to an omnivorous diet. The only trial we found switched 14 active men from a traditional Mediterranean diet to a vegan version for 4 weeks, keeping calories and macronutrients the same. Fat burning during exercise, heart rate, and perceived effort didn’t change (López-Moreno, 2025b). But the study wasn’t randomized, had no control group, and didn’t measure performance. So there’s no solid evidence on how a vegan diet affects endurance performance.

Exercise recovery

Some athletes say they recover faster after going vegan. Three small studies have compared vegans and meat-eaters after a bout of muscle-damaging exercise, tracking soreness, strength, and blood markers of muscle damage for two to three days (Table 3).

Table 3. Recovery after muscle-damaging exercise in vegans and meat-eaters

Study	Participants	Protein (g/kg/day), vegan vs. omnivore	Exercise	Follow-up	Result
Njeim, 2024	27 vegans, 27 omnivores; untrained women	1.06 vs. 1.21	Leg press, chest press, leg curl, arm curl	48 hours	Same self-rated soreness. Vegans did better on 7 of 28 measures (6 pressure-pain sites, right grip strength); none significant after correction for multiple comparisons.
Vasenina, 2025	10 vegans, 10 omnivores; recreationally trained	1.4 vs. 1.6	Downhill running	72 hours	No differences in recovery.
Mendes-Netto, 2026	7 vegans, 7 omnivores; resistance-trained	1.0 vs. 2.1	Squat and leg press to failure	72 hours	No differences in blood markers of muscle damage, jump height, or range of motion. Vegans more sore on 1 of 2 soreness measures; not significant after correction for multiple comparisons.

Each study measured many outcomes, and none of the differences held up after correcting for that. Because participants chose their own diets, differences in age, training, or protein intake could explain the results. So far, there’s no solid evidence that vegans recover differently than meat-eaters.

Iron

Iron deficiency, even without anemia, can limit athletic performance (Thomas, 2016), and it’s common in athletes, especially women: depending on the study, about 15–35% of female athletes are iron deficient, compared to about 3–11% of male athletes (Sim, 2019). Menstrual blood loss, red blood cells broken by the impact of running (foot-strike hemolysis), and iron lost in sweat, urine, and feces all add to athletes’ needs, and the ACSM says female athletes’ iron requirements may be up to 70% higher than the estimated average requirement (Thomas, 2016).

Plant foods contain only non-heme iron, which is absorbed less well than the heme iron in meat, and vegetarians generally have lower iron stores than meat-eaters (see Iron status of vegetarians). With menstrual losses and the demands of distance running on top of that, female vegan distance runners may be at higher risk of iron deficiency than other athletes.

Do vegan athletes have lower iron stores?

In recreational runners in Germany, who ran about 3 hours a week, iron stores (measured as ferritin) didn’t differ between 18 vegan, 16 lacto-ovo vegetarian, and 16 omnivore women (Nebl, 2019). Depleted iron stores (ferritin below 15 µg/L) were found in 5 of the vegan women, 6 of the lacto-ovo vegetarians, and 7 of the omnivores. There’s no agreement on the ferritin level that signals iron deficiency; suggested cutoffs range from below 10 to below 35 µg/L (Thomas, 2016).

In experienced rock climbers, 5 vegan or vegetarian women had lower ferritin than 15 omnivore women (33 vs. 58 µg/L; Gibson-Smith, 2020); the study combined vegans with vegetarians, and the difference was borderline (p = 0.05).

We found no studies of vegan distance runners or competitive endurance athletes, so the advice below is based on what’s known about female athletes and vegetarians in general.

What should vegan athletes do?

The ACSM recommends that athletes at greatest risk, including distance runners and vegetarians, have their iron status checked regularly and aim for more iron than the RDA, which is 18 mg/day for women aged 19–50 and 8 mg/day for men (Thomas, 2016). The Institute of Medicine estimates that vegetarians need 1.8 times the RDA, about 32 mg/day for women and 14 mg/day for men, though this may overstate some vegetarians’ needs (see Iron RDA and vegetarians). To get more iron from plant foods:

• Eat iron-rich foods such as legumes, tofu, tempeh, dark leafy greens, and iron-fortified cereals; see Iron content of plant foods for more.
• Include foods high in vitamin C at meals, such as an orange, a cup of strawberries, or a quarter cup of red or yellow peppers; see Vitamin C content of plant foods for more.
• Avoid tea and coffee within an hour of meals.
• Cook acidic foods, such as tomato sauce, in a cast-iron pan.

The ACSM doesn’t recommend taking iron supplements without testing first: supplements aren’t thought to improve performance unless iron is low, and they can cause stomach upset. Athletes who are low in iron should work with a physician; correcting iron-deficiency anemia can take 3 to 6 months (Thomas, 2016).

Energy and fiber

Athletes who don’t eat enough to cover their training for weeks or months can experience relative energy deficiency in sport (REDs); symptoms include disrupted menstrual periods and hormone production, weakened bones, and impaired training and performance (López-Moreno, 2026b).

Vegan diets tend to be high in fiber and low in energy density, which can, theoretically, make people feel full before they’ve eaten enough to fuel heavy training (Cialdella-Kam, 2016; López-Moreno, 2026b). We found no study meeting our criteria showing that vegan athletes are more likely to have low energy availability, and a 2026 review of female athletes concluded that the risk depends more on whether athletes eat enough than on whether they’re vegetarian (López-Moreno, 2026b). The same review noted that a vegan or vegetarian diet is occasionally used to hide an eating disorder, particularly in sports that emphasize leanness. Irregular or missing periods can be a sign of low energy availability (Cialdella-Kam, 2016).

What should vegan athletes do?

• During heavy training, include energy-dense foods such as nuts, nut butters, dried fruit, and plant oils. Eat on a regular schedule, rather than waiting until you’re hungry, since hard training and high-fiber meals can blunt appetite (Cialdella-Kam, 2016).
• Smoothies, such as fruit blended with soy milk, are an easy way to add calories. Adding protein powder is a low-volume way to obtain more calories and protein.

Fiber can also cause an upset stomach during exercise. For the meal before a competition, foods that are low in fat and fiber, with a low to moderate amount of protein, are generally best, because they’re less likely to cause stomach problems and leave the stomach faster (Thomas, 2016). Going vegan doesn’t necessarily cause problems: in a 4-week study, active men whose fiber intake rose from 31 to 41 grams a day on a vegan diet reported no digestive complaints (López-Moreno, 2025b). Athletes who have persistent gut symptoms during exercise may want to try a low-FODMAP diet; see Low-FODMAP Diet for Vegans.

Bone stress injuries

Bone stress injuries, including stress fractures, are a common overuse injury in athletes, affecting 10% to 31% of track and field athletes in some studies (Lappe, 2008); low energy availability raises the risk (López-Moreno, 2026b). Vegans also tend to eat less calcium than meat-eaters, which might increase risk.

In a randomized trial of 5,201 female U.S. Navy recruits, 2,000 mg/day of calcium plus 800 IU/day of vitamin D during 8 weeks of basic training reduced stress fractures from 6.6% to 5.3% (Lappe, 2008), so about 1 in 77 recruits avoided a stress fracture (1 / (0.066 – 0.053) = 77). The recruits reported eating less than one serving of dairy a day, which the authors estimated provided about 300 mg of calcium, but the study didn’t measure total calcium intake. This study suggests that a calcium plus vitamin D supplement can prevent stress fractures in young women who eat little dairy.

Vegan athletes, especially female distance runners, should make sure they eat enough calories, protein, and meet the RDA for calcium (1,000 mg/day for most adults) and vitamin D (600 IU/day for most adults). More info: Calcium and Vitamin D.

Creatine

Creatine supplies muscles with energy for short, intense effort. The body stores it in muscle, mostly as phosphocreatine, which rapidly regenerates ATP, which is the immediate fuel for muscle contraction.

Creatine is among the most studied sports supplements, and the Office of Dietary Supplements (ODS) summarizes the evidence as generally showing a benefit for high-intensity, intermittent activity: it may increase strength, power, and work from maximal muscle contractions, and over time helps the body adapt to training. It’s of little value for endurance sports (ODS, 2024).

The liver and kidneys make about 1 g of creatine a day (ODS, 2024). Meat and fish add more: in a controlled feeding study, an omnivorous diet provided 0.66–1.00 g of creatine a day, while a lacto-ovo-vegetarian diet provided only 0.04–0.07 g (Lukaszuk, 2002). Vegan diets provide none. For creatine, then, lacto-ovo vegetarians are in nearly the same position as vegans, and the research below treats them together.

Without supplementation, vegetarians and vegans have lower muscle creatine: muscle biopsies find vegetarians to have about 10% (117 vs. 130 mmol/kg of dry muscle; Burke, 2003) and about 15% (107 vs. 125; Watt, 2004) lower levels than meat-eaters.

Stores fall fairly quickly when meat is removed. When omnivores switched to a lacto-ovo-vegetarian diet, muscle creatine dropped about 10% in 3 weeks (Lukaszuk, 2002) and about 15% after 3 months (Blancquaert, 2018), reaching the range of lifelong vegetarians within a few weeks or months.

Does creatine improve vegetarians’ athletic performance? Sometimes. Vegetarians and vegans taking creatine improved at repeated bursts of intense effort, such as jumping and high-repetition sets, but not at sprinting or maximum strength (Burke, 2003; López-Moreno, 2026).

Do vegetarians benefit more from creatine than meat-eaters? Probably not, or not by much: of the two studies that compared them directly, one found vegetarians gained more on a test of muscular endurance, which was 1 of 3 performance tests, while the other found no difference (Burke, 2003; Shomrat, 2000).

Does lower muscle creatine put vegans at a disadvantage? Probably not. In the one study that could test this, vegetarians and meat-eaters not taking creatine gained strength similarly over 8 weeks of training (Burke, 2003).

Is it worth taking? It may help, it appears safe, but the research is thin. The table below summarizes the studies.

Table 4. Creatine studies in vegetarians and vegans

Study	Who	Dose	How long	What creatine did
Burke, 2003	18 vegetarians, 24 meat-eaters, lifting weights	~17 g/day for 1 week, then ~4 g/day	8 weeks	More muscle and more reps before fatigue, in both groups. Vegetarians gained a bit more on 1 of 3 performance tests (muscular endurance).
López-Moreno, 2026	20 active vegans	~7 g/day, no loading phase	4 weeks	Jumped higher. No change in sprinting or strength.
Shomrat, 2000	7 vegetarians, 17 meat-eaters, cycling sprints	21 g/day	6 days	Power rose about 5% in both groups, with no advantage for vegetarians.

Nearly all creatine research, including the strength study in vegetarians (Burke, 2003), used creatine monohydrate. Some supplements claim other forms work better, but they haven’t been shown to be better, and they usually cost more (ODS, 2024). Creatine monohydrate is made by chemical synthesis, not from animal products, so it’s vegan (for example, see AlzChem).

A typical protocol is a loading phase of 20 g/day for 5–7 days followed by 3–5 g/day, or simply 3–6 g/day for 3–4 weeks without loading. Few safety concerns have been reported at these doses; the main effect is weight gain from water retention (ODS, 2024).

Carnitine

At this time, there’s no reason to believe most vegans’ athletic performance would benefit from carnitine supplements.

Carnitine carries fatty acids into mitochondria to be burned for energy. The Office of Dietary Supplements describes the evidence on carnitine for athletic performance as mixed and says more research is needed (ODS, 2023).

The liver and kidneys are thought to make enough for healthy people. Most dietary carnitine comes from meat: a typical omnivorous diet provides about 24–145 mg a day, compared to about 1 mg for a vegan diet (ODS, 2023). Vegetarians usually have lower blood carnitine than meat-eaters (Lombard, 1989; Stephens, 2011; Novakova, 2016), though two studies found no difference (Koeth, 2019) or higher levels (Lin, 2019). Dairy contains a little carnitine. One study found similar blood carnitine in vegans and lacto-ovo vegetarians (Lombard, 1989), but another found low levels more common in vegans (Krajcovicova-Kudlackova, 2000).

No studies have tested carnitine supplements specifically in vegans. Only one trial has tested whether carnitine improves vegetarians’ performance. Sixteen vegetarians, 2 of them vegan, and 8 meat-eaters took 2 g/day for 12 weeks. Carnitine raised the vegetarians’ muscle carnitine but didn’t improve maximal power or VO2 max in either group (Novakova, 2016). The study was small and had no placebo group.

Carnosine and beta-alanine

Carnosine is made in muscle from two amino acids, beta-alanine and histidine, and helps buffer the acid that builds up during intense exercise. The liver makes some beta-alanine, and small amounts come from meat, poultry, and fish; vegans get little or none from food. Eating carnosine doesn’t raise muscle carnosine much because it’s digested into its two amino acids, but beta-alanine supplements reliably do (ODS, 2024). The ACSM lists low carnosine intake as a possible concern for vegetarian athletes (Thomas, 2016). Most of the research below is in lacto-ovo vegetarians rather than vegans.

Do vegans have less carnosine in their muscles? Possibly, after many years. In a small study, 12 men who had been lacto-ovo vegetarian or vegan for at least 8 years had 26% less carnosine than meat-eaters in one of three leg muscles measured (Everaert, 2011). But when 15 meat-eating women switched to a lacto-ovo vegetarian diet (along with a placebo), their muscle carnosine, a secondary outcome in that study, didn’t change over 6 months (Blancquaert, 2018). Training may also raise it: 12 weeks of high-intensity interval training increased muscle carnosine by about a third in 9 vegetarian men who took no beta-alanine, while it didn’t change in 10 who didn’t train (de Salles Painelli, 2018). The study had no meat-eating group, so it can’t tell us whether vegetarians respond to training differently than meat-eaters.

Do beta-alanine supplements improve performance? It may modestly improve high-intensity efforts lasting about 1 to 4 minutes (Thomas, 2016), but the trials are mixed (ODS, 2024), and it’s unclear whether it improves strength (Trexler, 2015).

Do vegans benefit more from beta-alanine than meat-eaters do? This hasn’t been tested. In the diet-switching study above, a third group of women took a low dose of beta-alanine (0.4–0.8 g/day, well below the 3–6 g/day used in performance research) along with 1 g/day of creatine. Their muscle carnosine rose by about a quarter to two-fifths, but their performance on a cycling test didn’t change; however, the test averaged about 14 minutes (Blancquaert, 2018), which might be too long to show a benefit, since beta-alanine has shown little or no benefit for activities lasting more than 10 minutes (ODS, 2024).

So vegans may have somewhat less muscle carnosine after years without meat, but no one has tested whether that affects their performance or whether they get more out of beta-alanine than meat-eaters. For anyone considering it, the ODS covers dosing and side effects (ODS, 2024).

Thanks to Taylor Wolfram, MS, RDN, for her work on an earlier version of this section.

Taurine

Taurine is found in muscle and is sold as a sports supplement. Plant foods contain little or no taurine, and vegans have lower blood taurine than meat-eaters, though the body makes its own (see our article Taurine). No studies have tested taurine in vegan athletes.

Research. No study meeting our criteria has shown that taurine supplements improve exercise performance, and a week of supplements didn’t raise the amount of taurine in muscle:

• A 2018 meta-analysis of 10 trials reported that taurine modestly improved endurance, but it judged publication bias only from a plot, and 2 of its trials were in patients with heart failure, who had the largest benefits, so we excluded it (Waldron, 2018).
• A 2025 meta-analysis of 23 trials in which people took a single dose of taurine before exercising reported a small benefit, but the results varied too much between studies (I² = 61%), and the authors’ own test suggested publication bias, so we excluded it (Deng, 2025).
• In a small study of 8 men, a week of 5 g/day raised blood taurine sharply but didn’t raise the amount in muscle (Galloway, 2008).

Collagen

Collagen supplements, including gelatin, are made from animal skin, bones, or fish scales. They’re marketed to athletes for joint and tendon health and increased muscle. The body makes its own collagen from amino acids; adequate protein and vitamin C intake support collagen production. More info: Collagen.

Joint pain and tendons. Trials of collagen for exercise-related joint pain haven’t shown a meaningful benefit, and all of them were funded by collagen manufacturers:

• In a 24-week trial in 147 college athletes with joint pain from their sports, those taking 10 g/day of collagen reported less pain on several measures than those taking a placebo, but none of the differences held up after the preplanned correction for multiple comparisons (Clark, 2008).
• In a 12-week trial in 139 young athletes with knee pain, 5 g/day of collagen reduced pain during activity slightly more than placebo (Zdzieblik, 2017), but the difference was smaller than what is considered clinically meaningful (Bongers, 2020 citing Wandel, 2010).
• In a 12-week trial in 167 active adults aged 50 to 75 with knee pain, 10 g/day of collagen didn’t reduce pain more than placebo (Bongers, 2020).
• A pilot study of 20 people with Achilles tendinopathy who took collagen for 3 months was too small to draw conclusions (Praet, 2019).

Recovery. Collagen hasn’t improved recovery from hard exercise more than other proteins:

• In men whose muscles were weakened and sore after 30 minutes of downhill running, 25 g/day of collagen was no better than 25 g of dairy protein at restoring strength or reducing soreness or blood markers of muscle damage over the next 3 days, and neither protein did better than a placebo (Barclay, 2024).
• In young men doing 3 weeks of muscle-damaging training, taking 25 g of whey plus 20 g of collagen a day made no difference to recovery or strength compared with taking 45 g of whey. The trial was small, funded by a collagen manufacturer, and registered only after it was finished (Robberechts, 2024).

Muscle growth. There’s no reason to believe that vegans have less muscle growth because they lack collagen in their diet. The only training trial we found that compared collagen with the same amount of another protein found that collagen built less muscle:

• In a small 10-week training study, whey increased muscle thickness more than the same amount of collagen with added leucine, though strength and power improved similarly in both groups (Jacinto, 2022).
• Most other trials of collagen for muscle size or strength compared it with a placebo containing no protein. Since extra protein alone can increase muscle gains, those trials can’t show whether collagen does anything that the same amount of any protein wouldn’t, so we excluded them. These include a 2024 meta-analysis of 19 such trials (Bischof, 2024) and a trial whose comparison with whey was only exploratory (Zdzieblik, 2021). Trials that measured only short-term muscle protein synthesis, not muscle growth, were also excluded (Aussieker, 2023; Oikawa, 2020).

Citations

Barclay R, Coad J, Schraders K, Barnes MJ. Comparing the Effects of Collagen Hydrolysate and Dairy Protein on Recovery from Eccentric Exercise: A Double Blind, Placebo-Controlled Study. Nutrients. 2024;16(24):4389. | Randomly assigned 33 active men (vegetarians and vegans excluded) to 25 g/day of collagen hydrolysate, 25 g/day of dairy protein, or a carbohydrate placebo with the same calories, for 3 days after 30 minutes of downhill running. Soreness, strength, jump height, running economy, and blood markers of muscle damage and inflammation didn’t differ among the groups. Prospectively registered (ACTRN12622000529741), with soreness, mid-thigh pull strength, and running economy as primary outcomes. Funded by the New Zealand government; the collagen came from a cattle-hide supplier listed as a secondary sponsor. Small.

Blancquaert L, Baguet A, Bex T, Volkaert A, Everaert I, Delanghe J, Petrovic M, Vervaet C, De Henauw S, Constantin-Teodosiu D, Greenhaff P, Derave W. Changing to a vegetarian diet reduces the body creatine pool in omnivorous women, but appears not to affect carnitine and carnosine homeostasis: a randomised trial. Br J Nutr. 2018 Apr;119(7):759-770.

Bongers CCWG, Ten Haaf DSM, Catoire M, et al. Effectiveness of collagen supplementation on pain scores in healthy individuals with self-reported knee pain: a randomized controlled trial. Appl Physiol Nutr Metab. 2020;45(7):793-800. | Randomly assigned 200 active adults aged 50 to 75 with knee pain, who were training for a multi-day walking event, to 10 g/day of collagen peptides or maltodextrin for 12 weeks; 167 were analyzed. Knee pain fell similarly in both groups (by 1.6 and 1.9 points on a 10-point scale). Registered (NTR5825). Supported by Rousselot, the collagen manufacturer.

Burke DG, Chilibeck PD, Parise G, Candow DG, Mahoney D, Tarnopolsky M. Effect of creatine and weight training on muscle creatine and performance in vegetarians. Med Sci Sports Exerc. 2003 Nov;35(11):1946-55. | Randomly assigned 42 recreational athletes to creatine or a placebo for 8 weeks: 18 vegetarians (3 vegan, 15 lacto-ovo, all vegetarian for at least 3 years) and 24 nonvegetarians. All participants followed the same supervised resistance-training program. Before supplementation, muscle biopsies showed that vegetarians had lower total creatine than nonvegetarians (117 vs. 130 mmol/kg of dry muscle). Creatine helped both diet groups: those taking it gained more lean tissue, increased their bench press more, and enlarged their type II muscle fibers more than those on placebo. Leg press strength increased with training but was unaffected by creatine. Participants taking creatine also trained at a higher volume, which the authors suggest explains creatine’s effects—by allowing more work in each session. Vegetarians taking creatine did better than nonvegetarians taking creatine on four measures: muscle total creatine, phosphocreatine, lean tissue mass (2.4 vs. 1.9 kg), and total work performed during 50 maximal knee extensions and flexions. Notably, the diet groups didn’t differ in bench press, leg press, or muscle fiber area—so, of the performance tests, vegetarians out-gained nonvegetarians only in muscular endurance, not maximal strength. This is the only trial to combine creatine supplementation with a resistance-training program and compare vegetarians to omnivores, and it’s the main basis for the idea that vegetarians respond better to creatine. But treat its results cautiously. The study measured roughly 18 outcomes and reported all results as “P

Cialdella-Kam L, Kulpins D, Manore MM. Vegetarian, Gluten-Free, and Energy Restricted Diets in Female Athletes. Sports (Basel). 2016;4(4):50.

Clark KL, Sebastianelli W, Flechsenhar KR, et al. 24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Curr Med Res Opin. 2008;24(5):1485-1496. | Randomly assigned 147 varsity and club athletes at Penn State with activity-related joint pain to 10 g/day of collagen hydrolysate or a placebo for 24 weeks; 97 were analyzed. The collagen group reported less pain on 6 of 15 primary measures (p = 0.007 to 0.039), but none passed the Bonferroni-Holm correction the authors had specified. A post hoc analysis of knee pain looked more favorable. The trial began in 2005 and reports no registration. Sponsored by Gelita, the collagen manufacturer, and one author worked for Gelita.

de Salles Painelli V, Nemezio KM, Pinto AJ, Franchi M, Andrade I, Riani LA, Saunders B, Sale C, Harris RC, Gualano B, Artioli GG. High-Intensity Interval Training Augments Muscle Carnosine in the Absence of Dietary Beta-alanine Intake. Med Sci Sports Exerc. 2018 Nov;50(11):2242-2252. | Randomly assigned 20 vegetarian men to 12 weeks of high-intensity interval training on a cycle ergometer or no training; one man in the training group dropped out. Muscle carnosine rose from 15.8 to 20.6 mmol/kg of dry muscle in the training group and didn’t change in the controls. The study was small, had no meat-eater group, and we found no trial registration.

Domić J, Grootswagers P, Pinckaers PJ, Melchers M, van Loon LJ, de Groot LC. A self-selected vegan diet reduces skeletal muscle mass in healthy older adults: a randomized controlled trial. Am J Clin Nutr. 2026 Sep;124(3):101416.

Durkalec-Michalski K, Domagalski A, Główka N, Kamińska J, Szymczak D, Podgórski T. Effect of a Four-Week Vegan Diet on Performance, Training Efficiency and Blood Biochemical Indices in CrossFit-Trained Participants. Nutrients. 2022 Feb 20;14(4):894.

Everaert I, Mooyaart A, Baguet A, Zutinic A, Baelde H, Achten E, Taes Y, De Heer E, Derave W. Vegetarianism, female gender and increasing age, but not CNDP1 genotype, are associated with reduced muscle carnosine levels in humans. Amino Acids. 2011 Apr;40(4):1221-9. | Cross-sectional comparison of 12 male vegetarians with 38 male meat-eaters; the vegetarians were about 7 years older on average. Vegetarians had lower carnosine in the gastrocnemius (26%, p = 0.009), which remained significant after adjusting for age. The study didn’t correct for comparing three muscles; the unadjusted gastrocnemius result would pass a Bonferroni correction, but the paper doesn’t report the age-adjusted p-value.

Galloway SD, Talanian JL, Shoveller AK, Heigenhauser GJ, Spriet LL. Seven days of oral taurine supplementation does not increase muscle taurine content or alter substrate metabolism during prolonged exercise in humans. J Appl Physiol. 2008;105(2):643-651.

Gibson-Smith E, Storey R, Ranchordas M. Dietary Intake, Body Composition and Iron Status in Experienced and Elite Climbers. Front Nutr. 2020 Aug 5;7:122. | Cross-sectional study of 40 experienced climbers (20 women, 20 men); 5 were vegan and 6 vegetarian, and the two were combined for analysis. Ferritin was lower in the 5 vegan and vegetarian women than in the 15 omnivorous women (33.2 vs. 57.5 µg/L, p = 0.05). Vegan and vegetarian women didn’t differ significantly (30.7 vs. 37.0 µg/L), though both groups were small. The study measured many outcomes, and the ferritin comparison by diet wasn’t its main aim.

Hevia-Larraín V, Gualano B, Longobardi I, Gil S, Fernandes AL, Costa LAR, Pereira RMR, Artioli GG, Phillips SM, Roschel H. High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Med. 2021 Jun;51(6):1317-1330.

Isenmann E, Eggers L, Havers T, Schalla J, Lesch A, Geisler S. Change to a Plant-Based Diet Has No Effect on Strength Performance in Trained Persons in the First 8 Weeks-A 16-Week Controlled Pilot Study. Int J Environ Res Public Health. 2023 Jan 19;20(3):1856.

Jacinto JL, Nunes JP, Gorissen SHM, Capel DMG, Bernardes AG, Ribeiro AS, Cyrino ES, Phillips SM, Aguiar AF. Whey Protein Supplementation Is Superior to Leucine-Matched Collagen Peptides to Increase Muscle Thickness During a 10-Week Resistance Training Program in Untrained Young Adults. Int J Sport Nutr Exerc Metab. 2022;32(3):133-143. | Randomly assigned 36 untrained young adults to 35 g/day of whey or 35 g/day of collagen peptides plus 2 g of leucine (3 g leucine in each) during a supervised 10-week resistance training program; 22 finished and were analyzed. Thigh muscle thickness rose 8.4% with whey vs. 5.6% with collagen, and biceps thickness 10.1% vs. 6.0% (both p

Koeth RA, Lam-Galvez BR, Kirsop J, et al. l-Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans. J Clin Invest. 2019;129(1):373-387.

Krajcovicova-Kudlackova M, Simoncic R, Bederova A, Babinska K, Beder I. Correlation of carnitine levels to methionine and lysine intake. Physiol Res. 2000;49(3):399-402.

Lappe J, Cullen D, Haynatzki G, Recker R, Ahlf R, Thompson K. Calcium and vitamin D supplementation decreases incidence of stress fractures in female navy recruits. J Bone Miner Res. 2008;23(5):741-749. | Randomly assigned 5,201 female Navy recruits to 2,000 mg/day calcium plus 800 IU/day vitamin D or a placebo during 8 weeks of basic training. By intention to treat, 5.3% of the supplemented group and 6.6% of the placebo group had a stress fracture (relative risk 0.80, 95% CI 0.64 to 0.99; the paper gives the p-value as 0.0026 in the abstract and 0.026 in the results). About 22% of recruits withdrew from the study. The recruits reported less than one serving of dairy a day, which the authors estimated provided about 300 mg of calcium; total calcium intake wasn’t measured. Recruitment ran from 2001 to 2006, and the paper reports no registration, so we judged it by its stated aim. Funded by the U.S. Department of Defense; GSK Consumer Healthcare supplied the supplements.

Lin TJ, Tang SC, Liao PY, Dongoran RA, Yang JH, Liu CH. A comparison of L-carnitine and several cardiovascular-related biomarkers between healthy vegetarians and omnivores. Nutrition. 2019 Oct;66:29-37.

Lombard KA, Olson AL, Nelson SE, Rebouche CJ. Carnitine status of lactoovovegetarians and strict vegetarian adults and children. Am J Clin Nutr. 1989 Aug;50(2):301-6.

López-Moreno M, Fresán U, Del Coso J, Muñoz A, Aguilar-Navarro M, Iglesias-López MT, Amaro-Gahete FJ, Gutiérrez-Hellín J. The OMNIVEG Study: Effects of Transitioning from a Traditional to a Vegan Mediterranean Diet on Fat Oxidation During Exercise. Nutrients. 2025;17(14):2274. | Fourteen physically active men followed a traditional Mediterranean diet for 3 weeks, then, after a 1-week break, an isocaloric vegan Mediterranean diet for 4 weeks, with macronutrients matched. Peak fat oxidation (0.32 vs. 0.35 g/min), the exercise intensity at which it occurred, heart rate, and perceived exertion didn’t differ. Fiber rose from 31 to 41 g/day, and no one reported digestive problems. The diet order wasn’t randomized, and performance wasn’t measured. Registered (NCT06008886) before recruitment; university-funded.

López-Moreno M, Muñoz A, Aguilar-Navarro M, Gutiérrez-Hellín J, Franco-Andrés A, López-López P, Crespo-Cañizares A, Marrero-Fernández P, Forbes SC. Does creatine supplementation improve strength and power in physically active individuals on a vegan diet? A randomized, triple-blind, placebo-controlled trial. Eur J Appl Physiol. 2026 Oct;126(10):5521-5532. | Randomly assigned 20 physically active vegans (10 women, 10 men, aged 18–45, vegan for at least 6 months) to 0.1 g/kg of creatine monohydrate per day or a placebo for 4 weeks, with no loading phase. Participants continued their usual exercise routines, including resistance training, but without a standardized training program. In the creatine group, performance improved on a repeated-jump test. The group also jumped higher in a standing vertical jump, but that finding probably doesn’t hold up once you account for the many outcomes the study measured. The study registered five primary outcomes before it began, but the published paper lists only the standing vertical jump as primary — the one finding that doesn’t hold up. There were no differences between the groups in a 30-meter sprint, handgrip strength, or an isometric mid-thigh pull. This trial found that creatine improved performance on a repeated-jump test, but with only 10 people per group and many outcomes measured, the finding needs replication. Because it lacked an omnivore group, it can’t tell us whether vegans benefit more than meat-eaters. This study reported gains in muscle mass and losses in fat, but we don’t include them here. Body composition was measured by bioelectrical impedance, which estimates total body water and infers muscle and fat from it — so the water creatine draws into muscle is counted as muscle. The figures in the abstract (a 0.3 kg gain in muscle mass and a 1.4 kg loss of fat) also don’t match the paper’s tables, which report 1.5 kg and 1.1 kg.

López-Moreno M, Perez-Diaz-Del-Campo N, Villa N, Leszczyńska PM, Sánchez-Infante J, Marrero-Fernández P. Vegetarian diets in female athletes: performance, health outcomes, and the implementation gap. Front Nutr. 2026;13:1901139.

Lukaszuk JM, Robertson RJ, Arch JE, Moore GE, Yaw KM, Kelley DE, Rubin JT, Moyna NM. Effect of creatine supplementation and a lacto-ovo-vegetarian diet on muscle creatine concentration. Int J Sport Nutr Exerc Metab. 2002 Sep;12(3):336-48.

Martini GL, Schemes MB, Strey B, Schneider CD, de Souza CG, Pinto RS. No Differences in Muscular Adaptations to Long-Term Resistance Training Between Young Strict Vegetarian and Non-Vegetarian Women. Scand J Med Sci Sports. 2026 Feb;36(2):e70224.

Mendes-Netto RS, de Carvalho FG, de Souza AC, et al. Similar Muscle Recovery but Greater Soreness in Active Vegans on Low-Protein Diets Compared to High-Protein Omnivores Following Exercise-Induced Damage. Nutr Bull. 2026;51:389-406.

Monteyne AJ, Coelho MO, Murton AJ, Abdelrahman DR, Blackwell JR, Koscien CP, Knapp KM, Fulford J, Finnigan TJ, Dirks ML, Stephens FB, Wall BT. Vegan and omnivorous high protein diets support comparable daily myofibrillar protein synthesis rates and skeletal muscle hypertrophy in young adults. J Nutr. 2023 Feb 21:S0022-3166(23)12680-0.

Nebl J, Schuchardt JP, Ströhle A, Wasserfurth P, Haufe S, Eigendorf J, Tegtbur U, Hahn A. Micronutrient Status of Recreational Runners with Vegetarian or Non-Vegetarian Dietary Patterns. Nutrients. 2019 May 22;11(5):1146. | Cross-sectional study of 81 recreational runners aged 18–35 in Hannover, Germany (28 vegans, 26 lacto-ovo vegetarians, 27 omnivores) who ran 2–5 times a week. Diet was self-reported by questionnaire. Women’s average ferritin was 32.1 µg/L in vegans, 23.9 in lacto-ovo vegetarians, and 25.9 in omnivores (no significant differences). Ferritin was below 15 µg/L in 5 of 18 vegan, 6 of 16 lacto-ovo vegetarian, and 7 of 16 omnivorous women. Hemoglobin was below 12 g/dL (the World Health Organization’s cutoff for anemia in women) in 4 vegan, no lacto-ovo vegetarian, and 3 omnivorous women, but none had the small red blood cells typical of iron-deficiency anemia. Iron supplements were used by 18% of vegans, 15% of lacto-ovo vegetarians, and 11% of omnivores. Among men, omnivores had higher ferritin than vegans or lacto-ovo vegetarians (115 vs. about 64 µg/L).

Njeim P, Faust A, Casgrain J, Karelis AD, Boutros GH. Delayed Onset Muscle Soreness Following Acute Resistance Exercise in Untrained Females: A Comparative Study Between Vegans and Omnivores. Int J Sports Med. 2024 Dec;45(14):1099-1106.

Novakova K, Kummer O, Bouitbir J, Stoffel SD, Hoerler-Koerner U, Bodmer M, Roberts P, Urwyler A, Ehrsam R, Krähenbühl S. Effect of L-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians. Eur J Nutr. 2016 Feb;55(1):207-17. | Gave 2 g/day of L-carnitine for 12 weeks to 16 vegetarian men (2 vegan) and 8 omnivorous men, with no placebo group. Before supplementation, the vegetarians had 10% lower plasma carnitine but similar muscle carnitine. Supplementation raised muscle carnitine by 13% in vegetarians and not at all in omnivores, but it didn’t change maximal workload, VO2 max, or muscle energy metabolites in either group. Lonza supplied the carnitine and paid part of one author’s salary.

Office of Dietary Supplements. National Institutes of Health. Carnitine: Fact Sheet for Health Professionals. Updated April 17, 2023. Accessed October 16, 2026.

Office of Dietary Supplements. National Institutes of Health. Dietary Supplements for Exercise and Athletic Performance. Accessed October 17, 2026.

Praet SFE, Purdam CR, Welvaert M, et al. Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients. Nutrients. 2019;11(1):76. | A pilot crossover trial in 20 people with chronic Achilles tendinopathy doing a 6-month calf-strengthening program, who took 5 g/day of collagen peptides or a placebo for 3 months each. Scores improved more during the collagen months, but the authors say the study wasn’t powered to show a difference and that no firm conclusions can be drawn. Registered (ANZCTR 12615001035516). Funded by Gelita, the collagen manufacturer.

Robberechts R, Poffé C, Ampe N, Bogaerts S, Hespel P. Partly Substituting Whey for Collagen Peptide Supplementation Improves Neither Indices of Muscle Damage Nor Recovery of Functional Capacity During Eccentric Exercise Training in Fit Males. Int J Sport Nutr Exerc Metab. 2024;34(2):69-78. | Randomly assigned 22 young men to 45 g/day of whey or 25 g of whey plus 20 g of collagen peptides during 3 weeks of one-leg eccentric training. The paper’s primary outcomes, jump height and isometric strength, didn’t differ between groups, and neither did dynamic strength, creatine kinase, or soreness. Registered only after the study was done (NCT05425407), so we can’t confirm the primary outcomes were chosen in advance; the registry also lists a different whey dose than the paper. Funded by Rousselot, the collagen manufacturer, which was allowed to comment on the manuscript. Small.

Shomrat A, Weinstein Y, Katz A. Effect of creatine feeding on maximal exercise performance in vegetarians. Eur J Appl Physiol. 2000 Jul;82(4):321-5. | Compared creatine’s effects in 7 vegetarians and 9 meat-eaters, all healthy and active but not highly trained. Both groups took 21 g of creatine per day (3 doses of 7 g) for 6 days. A third group of 8 meat-eaters received glucose as a placebo. The trial included no resistance-training program. Performance was measured as three 20-second maximal cycling sprints separated by 4 minutes of recovery. As expected, vegetarians had lower blood creatine levels than meat-eaters before supplementation (11 vs. 23–24 µmol/L). After supplementation, average power output rose about 5% in both creatine groups, with no difference between vegetarians and meat-eaters. Peak power rose about 5% in the meat-eaters taking creatine but not in the vegetarians. Both creatine groups gained about 1 kg of body weight. The placebo group didn’t improve on any measure. Since there was no vegetarian placebo group, this study can’t tell us whether creatine improved their performance beyond what practice alone would produce. But it can compare the two creatine groups, and it found no advantage for vegetarians—if anything, the opposite on peak power. The study was small, and the authors didn’t standardize or monitor what participants ate during the trial.

Sim M, Garvican-Lewis LA, Cox GR, Govus A, McKay AKA, Stellingwerff T, Peeling P. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019 Jul;119(7):1463-1478.

Stephens FB, Marimuthu K, Cheng Y, Patel N, Constantin D, Simpson EJ, Greenhaff PL. Vegetarians have a reduced skeletal muscle carnitine transport capacity. Am J Clin Nutr. 2011 Sep;94(3):938-44.

Tagawa R, Watanabe D, Ito K, Otsuyama T, Nakayama K, Sanbongi C, Miyachi M. Synergistic Effect of Increased Total Protein Intake and Strength Training on Muscle Strength: A Dose-Response Meta-analysis of Randomized Controlled Trials. Sports Med Open. 2022 Sep 4;8(1):110.

Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet 2016;116:501-528.

Trexler ET, Smith-Ryan AE, Stout JR, Hoffman JR, Wilborn CD, Sale C, Kreider RB, Jäger R, Earnest CP, Bannock L, Campbell B, Kalman D, Ziegenfuss TN, Antonio J. International society of sports nutrition position stand: Beta-Alanine. J Int Soc Sports Nutr. 2015;12:30.

Vasenina E, Sterner DA, Mangum LC, Stout JR, Fukuda DH. Effects of Vegan and Omnivore Diet on Post-Downhill Running Economy and Muscle Function. J Am Nutr Assoc. 2025;44(3):235-244.

Excluded research

Askow AT, Barnes TM, Zupancic Z, et al. Impact of Vegan Diets on Resistance Exercise-Mediated Myofibrillar Protein Synthesis in Healthy Young Males and Females: A Randomized Controlled Trial. Med Sci Sports Exerc. 2025 Apr 4. | Found no difference in myofibrillar protein synthesis between 40 omnivores randomized to a 9-day vegan or omnivorous diet at a moderate protein intake (~1.14 g/kg), regardless of whether protein was evenly distributed across meals or skewed toward one. Excluded because it measured only short-term muscle protein synthesis, not muscle mass or strength; in a 16-week training study, the short-term rise in muscle protein synthesis didn’t predict how much muscle people gained (Mitchell, 2014).

Aussieker T, Hilkens L, Holwerda AM, Fuchs CJ, Houben LHP, Senden JM, van Dijk JW, Snijders T, van Loon LJC. Collagen Protein Ingestion during Recovery from Exercise Does Not Increase Muscle Connective Protein Synthesis Rates. Med Sci Sports Exerc. 2023 May 19. | After a session of squats, 30 g of whey raised muscle protein synthesis above a placebo drink and 30 g of collagen didn’t, though whey and collagen didn’t differ significantly from each other. Excluded because it measured only short-term muscle protein synthesis, not muscle mass or strength; in a 16-week training study, the short-term rise in muscle protein synthesis didn’t predict how much muscle people gained (Mitchell, 2014).

Baguet A, Everaert I, De Naeyer H, Reyngoudt H, Stegen S, Beeckman S, Achten E, Vanhee L, Volkaert A, Petrovic M, Taes Y, Derave W. Effects of sprint training combined with vegetarian or mixed diet on muscle carnosine content and buffering capacity. Eur J Appl Physiol. 2011 Oct;111(10):2571-80. | Nineteen meat-eaters did 5 weeks of sprint training on either a lacto-ovo vegetarian or a meat-containing diet. Muscle carnosine didn’t change significantly in either group, and sprint performance improved equally. Excluded because 5 weeks is too short to detect changes in muscle carnosine, which turns over slowly, and we found no trial registration.

Bartholomae E, Nadalet C, Johnston CS. Influences of vegan status on protein intake, lean body mass, and strength in lightly active, young women: A cross-sectional study. Nutrition. 2026 Jan 7;145:113102. | Cross-sectional.

Bischof K, Moitzi AM, Stafilidis S, König D. Impact of Collagen Peptide Supplementation in Combination with Long-Term Physical Training on Strength, Musculotendinous Remodeling, Functional Recovery, and Body Composition in Healthy Adults: A Systematic Review with Meta-analysis. Sports Med. 2024;54(11):2865-2888. | Pooled 19 randomized trials of collagen peptides with exercise training and found small benefits for strength (11 trials) and fat-free mass (8 trials). Excluded for muscle and strength outcomes because every trial’s placebo contained no protein, so the results can’t separate the effect of collagen from that of extra protein. Its tendon and recovery analyses each pooled fewer than 10 trials.

Bonne TC, Arthemalle V, Doherty CS, et al. Muscle creatine levels and sprint performance in young adult vegans and vegetarians after 7 days of creatine monohydrate supplementation. Physiol Rep. 2025 Sep;13(17):e70539. | Seven days of creatine loading raised muscle creatine in 15 vegans and vegetarians but didn’t improve repeated sprint performance. Excluded because the authors calculated the study would have needed 23 participants to detect a difference in performance, so the null result isn’t informative.

Boutros GH, Landry-Duval MA, Garzon M, Karelis AD. Is a vegan diet detrimental to endurance and muscle strength? Eur J Clin Nutr. 2020 Nov;74(11):1550-1555. | Compared 28 vegan and 28 omnivorous physically active young women; the vegans had a higher estimated VO2max and lasted longer on a submaximal cycling test, with similar strength. Cross-sectional.

Cárcamo-Regla R, Alcaide-Leyva JM, Zapata-Lamana R, Martorell-Pons M, Carrasco-Marín F, Molina-Recio G. Efficacy of a resistance training program on muscle mass and muscle strength in adults following a vegan versus omnivorous diet: A nonrandomized four-arm parallel clinical trial. Nutrition. 2025 Nov 28;148:113047. | No protein intake data reported; no muscle mass gains in any group; authors describe findings as exploratory, not causal.

Conrado de Souza A, da Silva Brandão M, Lima Oliveira D, Garcez de Carvalho F, Costa ML, Aragão-Santos JC, Santos do Nascimento MV, Silva-Grigoletto M, Mendes-Netto RS. Active vegetarians show better lower limb strength and power than active omnivores. Int J Sports Med. 2022 Jan 27. | Cross-sectional.

Damasceno YO, Leitão CVFS, de Oliveira GM, Andrade FAB, Pereira AB, Viza RS, et al. Plant-based diets benefit aerobic performance and do not compromise strength/power performance: a systematic review and meta-analysis. Br J Nutr. 2024;131:829-840. | Pooled 10 studies and reported that plant-based diets improved aerobic performance and didn’t affect strength or power. Excluded because only 4 studies contributed to the aerobic analysis (only 1 of them in vegans, counted twice in the vegan analysis), the analysis combined observational studies with trials, and the abstract and results report different numbers of studies and effect sizes.

Deng H, Song T, Yin M, Xu K, Zhong Y, Liu P, Sun S, Bin Naharudin MN, Yusof A, Fan X. Does One Shot Work? The Acute Impact of a Single Taurine Dose on Exercise Performance: A Meta-Analytic Review. Scand J Med Sci Sports. 2025;35(9):e70123. | Pooled 23 randomized trials (308 people) in which participants took a single dose of taurine 45 minutes to 2 hours before exercise, and found a small benefit (effect size 0.25). Excluded because heterogeneity was too high (I² = 61%) and the authors’ Egger test suggested publication bias. The authors rated 19 of the 23 trials as having some concerns or a high risk of bias.

Georgiou GD, Antoniou K, Antoniou S, Michelekaki EA, Zare R, Ali Redha A, Prokopidis K, Christodoulides E, Clifford T. Effect of Beta-Alanine Supplementation on Maximal Intensity Exercise in Trained Young Male Individuals: A Systematic Review and Meta-Analysis. Int J Sport Nutr Exerc Metab. 2024;34(6):397-412. | Pooled 18 trials in trained young men and found a small benefit for all-out efforts lasting 30 seconds to 10 minutes. Heterogeneity was acceptable (I² = 44%), but excluded because the authors didn’t assess publication bias. All the included studies excluded vegetarians.

Harris RC, Jones G, Hill CA, Kendrick IP, Boobis LH, Kim CK, Kim HJ, Dang VH, Edge J, Wise JA. The carnosine content of vastus lateralis in vegetarians and omnivores. FASEB J. 2007;21:A944. | Conference abstract, not indexed in PubMed. It compared female vegetarians with male sports science students, and men have more muscle carnosine than women.

Jo G, Tamrakar S, Sharma S, Koppolu S, Goldy EE, Kumar SIS. Comparative cross-sectional study of vegan and omnivorous diets and their impact on cardiac function among endurance athletes. Bioinformation. 2025;21(12):4350-4354. | Reported lower hemoglobin and ferritin in 40 vegan than in 40 omnivorous endurance athletes. Excluded because iron was a secondary measure in a study of heart function, results weren’t reported separately for the 23 women, and the paper doesn’t say which sports the athletes did or whether any took iron supplements.

Kaviani M, Shaw K, Chilibeck PD. Benefits of Creatine Supplementation for Vegetarians Compared to Omnivorous Athletes: A Systematic Review. Int J Environ Res Public Health. 2020 Apr 27;17(9):3041. | A narrative synthesis of nine studies with no pooled analysis, so it doesn’t meet our criteria for a meta-analysis. The authors also rated the studies they reviewed as having a moderate to high risk of bias. We cover the individual trials above.

López-Moreno M, Rossi EV, López-Gil JF, Marrero-Fernández P, Roldán-Ruiz A, Bertotti G. Are Plant-Based Diets Detrimental to Muscular Strength? A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Sports Med Open. 2025;11:62. | Pooled 8 randomized trials (188 participants) and found no difference in strength between plant-based and omnivorous diets, with no sign of publication bias. Excluded because it pooled fewer than 10 studies. Five of the 8 trials tested lacto-ovo vegetarian rather than vegan diets, three were funded by the beef industry, and in one, the plant-based group also received a training and lifestyle program that the control group didn’t.

Lukaszuk JM, Robertson RJ, Arch JE, Moyna NM. Effect of a defined lacto-ovo-vegetarian diet and oral creatine monohydrate supplementation on plasma creatine concentration. J Strength Cond Res. 2005 Nov;19(4):735-40. | Measured plasma creatine only; no performance outcome.

MacCormick VM, Hill LM, MacNeil L, Burke DG, Smith-Palmer T. Elevation of creatine in red blood cells in vegetarians and nonvegetarians after creatine supplementation. Can J Appl Physiol. 2004 Dec;29(6):704-13. | Measured creatine in red blood cells only; no performance outcome.

Nebl J, Haufe S, Eigendorf J, Wasserfurth P, Tegtbur U, Hahn A. Exercise capacity of vegan, lacto-ovo-vegetarian and omnivorous recreational runners. J Int Soc Sports Nutr. 2019 May 20;16(1):23. | Cross-sectional. Found no difference in maximal power output relative to body weight among 24 vegan, 26 lacto-ovo vegetarian, and 26 omnivorous recreational runners in Germany.

Oikawa SY, Kamal MJ, Webb EK, McGlory C, Baker SK, Phillips SM. Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial. Am J Clin Nutr. 2020;111(3):708-718. | Gave 22 older women 30 g of whey or collagen twice a day for 6 days, with one leg exercised twice. Whey raised muscle protein synthesis in both legs over the 6 days, and collagen didn’t, though collagen raised it briefly after the first exercise session. Excluded because it measured only short-term muscle protein synthesis, not muscle mass or strength; in a 16-week training study, the short-term rise in muscle protein synthesis didn’t predict how much muscle people gained (Mitchell, 2014).

Presti N, Rideout TC, Temple JL, Bratta B, Hostler D. Recovery after Exercise-Induced Muscle Damage in Subjects Following a Vegetarian or Mixed Diet. Nutrients. 2024;16(16):2711. | The vegetarian group could eat eggs and dairy (averaging 14 g/day of animal protein), and the number of vegans wasn’t reported.

Presti N, Rideout TC, Temple JL, Bratta B, Hostler D. Recovery of Strength After Exercise-Induced Muscle Damage in Vegetarians Consuming the Upper and Lower Ends of Protein Recommendations for Athletes. Nutrients. 2025 Mar 17;17(6):1046. | Protein intakes of 1.2 g/kg or 2.0 g/kg had no impact on recovery of strength, power, and soreness after a bout of exercise-induced muscle damage. Subjects could be lacto-ovo-vegetarian; no info was provided on whether any were vegan.

Raygoza C, Roberts A, Guidetti A, Cai O, Sangowdar P, Muriuki EN, et al. Plant-Based vs. Omnivore diets for athletic performance outcomes among recreational athletes in university dining halls: a randomized crossover study. Nutr J. 2026;25:42. | Randomly assigned the order in which 36 recreational athletes (16 runners and 20 resistance trainers) ate a plant-based diet and their usual omnivorous diet, for 4 weeks each. The runners’ distance on a 12-minute run (a primary outcome) didn’t differ between diets (2,622 vs. 2,658 m, p = 0.43), and neither did the resistance trainers’ strength. Excluded because the plant-based diet wasn’t vegan: fish was allowed once or twice a week, and eggs and dairy once a day.

Reid-McCann RJ, Brennan SF, Ward NA, Logan D, McKinley MC, McEvoy CT. Effect of Plant Versus Animal Protein on Muscle Mass, Strength, Physical Performance, and Sarcopenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Nutr Rev. 2025 Jul 1;83(7):e1581-e1603. | Most of the pooled trials weren’t in people doing resistance training. Only 10 of the 30 muscle mass trials included it. The plant-based diet trials were mostly in people with obesity or other health conditions. The overall analysis had substantial heterogeneity (I² = 62%).

Roberts AK, Busque V, Robinson JL, Landry MJ, Gardner CD. SWAP-MEAT Athlete (study with appetizing plant-food, meat eating alternatives trial) – investigating the impact of three different diets on recreational athletic performance: a randomized crossover trial. Nutr J. 2022 Nov 16;21(1):69. | Crossover trial comparing whole-food plant-based, plant-based meat alternative, and omnivorous diets over 4 weeks each with little washout period.

Saunders B, Elliott-Sale K, Artioli GG, Swinton PA, Dolan E, Roschel H, Sale C, Gualano B. β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. Br J Sports Med. 2017 Apr;51(8):658-669. | Pooled 40 placebo-controlled trials (1,461 participants) and found a small overall benefit (effect size 0.18). Excluded because about 72% of the variation in results reflected real differences between studies, well above our 50% limit, and publication bias was judged only by looking at a funnel plot.

Schemes MB, Martini GL, Strey BM, Guerini C, Pinto RS, Schneider CD. Dietary intake, body composition, and muscle function in resistance-untrained strict vegetarian and non-vegetarian women: an exploratory cross-sectional study. Appl Physiol Nutr Metab. 2025;50:1-8. | Cross-sectional.

Volpe-Fix AR, Salvalágio BR, Fix R, Gomes FS, Silva BM, Thomatieli-Santos RV. Vegetarian advantage in muscle performance: Novel evidence from controlled isokinetic assessments. Nutrition. 2026 Feb 24;147:113151. | Cross-sectional.

Waldron M, Patterson SD, Tallent J, Jeffries O. The Effects of an Oral Taurine Dose and Supplementation Period on Endurance Exercise Performance in Humans: A Meta-Analysis. Sports Med. 2018;48(5):1247-1253. | Pooled 10 trials and found that 1–6 g of taurine modestly improved endurance performance (effect size 0.40), with low heterogeneity (I² = 29%). Excluded because publication bias was judged only from a plot. Also, 2 of the 10 trials were in heart-failure patients, whose exercise time improved by 18% and 26%, compared with a few percent in most trials of healthy people; these trials likely pulled the pooled result up and say little about athletes.

Watt KKO, Garnham AP, Snow RJ. Skeletal muscle total creatine content and creatine transporter gene expression in vegetarians prior to and following creatine supplementation. Int J Sport Nutr Exerc Metab. 2004 Oct;14(5):517-31. | Seven vegetarians and 7 meat-eaters took creatine (0.4 g/kg/day) for 5 days in a crossover design. Vegetarians started with lower muscle creatine and gained more from supplementation. But the washout period between conditions was too short; 5 weeks later, the vegetarians’ muscle creatine still hadn’t returned to baseline. The authors state the sprint results can’t reliably distinguish vegetarians from meat-eaters, and the paper doesn’t report the performance data.

Zdzieblik D, Oesser S, Gollhofer A, König D. Improvement of activity-related knee joint discomfort following supplementation of specific collagen peptides. Appl Physiol Nutr Metab. 2017;42(6):588-595. | Randomly assigned 160 young athletes with activity-related knee pain to 5 g/day of collagen peptides or maltodextrin for 12 weeks; 139 finished. Pain during activity fell by 19.5 points on a 100-point scale with collagen and 13.9 with placebo. Excluded because the 5.6-point difference was smaller than the roughly 9-point minimum clinically important difference for this kind of pain scale. Funded by Gelita, the collagen manufacturer.

Zdzieblik D, Jendricke P, Oesser S, Gollhofer A, König D. The Influence of Specific Bioactive Collagen Peptides on Body Composition and Muscle Strength in Middle-Aged, Untrained Men: A Randomized Controlled Trial. Int J Environ Res Public Health. 2021;18(9):4837. | Middle-aged men doing resistance training took 15 g/day of collagen peptides, 15 g/day of whey, or a non-protein placebo for 12 weeks. Fat-free mass rose 3.4 kg with collagen, 2.3 kg with whey, and 1.8 kg with placebo; collagen beat placebo (the primary comparison), but collagen and whey didn’t differ significantly. Excluded because the main comparison was against a placebo with no protein, and the comparison with whey was exploratory. Registered (DRKS00008925). Partly funded by Gelita, which also supplied the collagen; one author is a co-inventor on collagen peptide patents.