Can you build muscle on a vegan diet?

The objection

“Plant protein carries less leucine, it is harder to digest, and in lab studies it switches on muscle building less than whey does. A 2025 meta-analysis of 30 trials found plant protein built less muscle than animal protein, and the gap was bigger in people lifting weights. Add the fact that vegans get almost no creatine from food, and anyone trying to build serious muscle without meat, eggs or whey is swimming against the current.”

The answer

Plant protein is a little less efficient gram for gram, and the trials suggest that what decides whether vegans keep up is eating enough of it [2][3][5][15]. Across 30 randomised trials pooled in a 2025 meta-analysis, plant protein produced slightly less muscle mass than animal protein, an effect the authors call small, while soy protein showed no difference from milk protein [1]. Strength did not differ significantly overall, although animal protein came out ahead for lower-body strength in trials of adults aged 60 and over [1]. In two trials that matched protein intake and training, from 2021 and 2023, people on vegan or almost entirely vegan diets gained muscle with no significant difference from people eating meat [2][3]. When older adults in a 2026 trial switched to a vegan diet of their own choosing, they ate less protein and lost muscle [15].

Does plant protein build less muscle than animal protein?

Plant protein builds slightly less muscle than animal protein on average, mainly when it is something other than soy. The 2025 meta-analysis, from Queen’s University Belfast, pooled 30 randomised trials with 1,538 participants and found a small advantage for animal protein on muscle mass, a standardised mean difference (SMD) of −0.20, where the authors count 0.2 as a small effect and 0.5 as moderate [1]. A negative number favours animal protein, and an interval that crosses zero means no clear difference.

Comparison (Reid-McCann et al., 2025) [1]	Trials	SMD (95% CI)
Muscle mass, all plant against all animal protein	30	−0.20 (−0.37 to −0.03)
Muscle mass, soy against milk protein	17	−0.02 (−0.20 to 0.16)
Muscle mass, rice, chia, oat or potato against milk protein	5	−0.58 (−1.06 to −0.09)
Muscle mass, plant-based against omnivorous diets	7	−0.51 (−0.91 to −0.11)
Muscle mass, trials with resistance training	10	−0.45 (−0.85 to −0.05)
Muscle mass, trials without resistance training	20	−0.10 (−0.27 to 0.08)
Muscle mass, trials in adults under 60	21	−0.28 (−0.50 to −0.06)
Muscle mass, trials in adults aged 60 and over	9	−0.05 (−0.32 to 0.23)
Lower-body strength	11	−0.19 (−0.44 to 0.05)
Upper-body strength	14	−0.12 (−0.51 to 0.26)

The rows that favour animal protein are the strongest evidence for the objection. The trials that included resistance training are the closest to building muscle, and there animal protein’s edge was larger, an effect the authors call small to moderate, but those ten trials had 335 participants between them and tested soy, rice and chia protein, and the review’s overall verdict was that any benefit of animal protein was slight [1]. The seven diet trials mostly moved people with overweight, type 2 diabetes or polycystic ovary syndrome onto plant-based or legume-based diets, three of them calorie-restricted weight-loss diets and only one with resistance training, so they say little about a planned diet for someone who lifts [1]. The edge on muscle mass came mainly from the trials in adults under 60, while trials in adults aged 60 and over found no clear difference in muscle mass, although there animal protein did better for lower-body strength (SMD −0.38, 95% CI −0.71 to −0.05) [1]. For healthy young adults, the authors wrote that animal or soy protein combined with resistance training appears to be “the optimal intervention for increasing muscle mass” [1].

Short-term lab studies point the same way. Leucine is the amino acid that does most to switch on muscle building, and many plant proteins carry less of it: whey protein is 11.0% leucine against 6.9% for soy and 7.2% for pea, so about 40 g of soy protein is needed to supply the 2.7 g of leucine in 25 g of whey, according to a 2021 review [5]. A 2026 meta-analysis of 12 studies of muscle protein synthesis found results slightly favoured animal protein, mostly from milk, but the differences were small and uncertain, with a modest advantage only in people aged 65 and over [4].

Plant proteins fall short in different amino acids, and the 2021 review lists blending them, eating more of them or fortifying them as ways round it [5]; protein combining covers the old rule about mixing them at every meal. Over longer periods the gap is harder to find: a 2026 meta-analysis of 18 trials lasting at least six months, with 1,893 participants and mostly soy protein, found no significant difference in lean mass or strength between plant and animal protein supplements, though seven of its eight authors list Danone Research as an affiliation [6].

What happens when vegans and meat-eaters train on the same protein?

Vegans and meat-eaters on the same high protein intake gained muscle at much the same rate in two small trials that tested it, though in one of them the plant-based diet allowed animal products on up to one day a week. In the 2021 São Paulo trial, 19 young men who were already vegan and 19 omnivores, all new to weight training, lifted twice a week for 12 weeks with their protein brought up to about 1.6 g per kilo of body weight a day, using soy protein for the vegans and whey for the omnivores [2]. Both groups gained 1.2 kg of leg lean mass on average, and none of the measures of muscle size or strength differed significantly between them, although the omnivores’ leg press rose by 117 kg against 97 kg for the vegans [2]. The men kept their own diets, so the groups were not randomised, and the trial was registered only after it had begun [2].

In the 2023 Exeter trial, 22 young adults with weight-training experience ate either a high-protein omnivorous diet or one that avoided animal products on at least six days a week, at about 2 g of protein per kilo a day, and trained five times a week for 10 weeks [3]. Seven of the ten in the plant-based group ate fully vegan, and 20 of the 22 were randomly assigned, the other two going straight into the plant-based group because they were already vegan [3]. Lean mass rose by 3.1 kg on the plant-based diet and 2.6 kg on the omnivorous one, and thigh muscle volume by 8.3% in both groups, with no significant difference between them [3]. Strength rose by similar amounts, and the one significant difference, in the percentage gain on the incline bench press, favoured the plant-based group [3]. That diet was built around mycoprotein, and the trial was funded by Marlow Foods, which employs one of the authors [3]. The Exeter team pointed out that the trial was not designed to test whether the diets were equivalent, and that its vegan volunteers found the protein target harder to reach [3]. Both trials were small, short and in healthy young people, so they show what a well-planned diet with plenty of protein can do rather than what any vegan diet will do.

Left to chance, protein can fall, and muscle with it. In a 2026 trial from Wageningen University, 72 healthy people aged 65 and over were randomly assigned to keep their usual diet, to switch to a vegan diet of their own choosing, or to switch and also start resistance exercise [15]. Those who went vegan without training ate about 19 to 28 g less protein a day than before, and over 12 weeks they lost an average of 0.61 litres of thigh muscle, against almost no change in those who kept their usual diet, while those who trained alongside the vegan diet cut their protein by a similar amount and still lost 0.35 litres [15]. The authors concluded that a self-selected vegan diet reduced protein intake and muscle mass in older adults, and that resistance exercise lessened the loss [15].

How much protein do you need to build muscle?

About 1.6 g of protein per kilo of body weight a day, or 112 g for someone weighing 70 kg, is the amount the International Olympic Committee’s 2018 consensus statement calls optimal for gaining muscle, and it notes no adverse effects up to 2.2 g [7]. A 2018 meta-analysis of 49 trials with 1,863 participants found that extra protein stopped adding to gains in fat-free mass beyond about 1.62 g per kilo a day, although this breakpoint fell short of statistical significance and its 95% confidence interval ran from 1.03 to 2.20 g, so its authors suggested about 2.2 g for anyone trying to get every last gain [8]. The same analysis puts protein in its place: supplements added 0.30 kg of fat-free mass and 2.49 kg to one-repetition-maximum strength on average, and the authors concluded that the training itself is the much more potent stimulus for gains in both muscle mass and strength [8]. The IOC suggests eating 0.3 to 0.5 g per kilo at a time, three or four times a day, including soon after training [7].

The 2021 review reasoned that people relying on plant protein may need a little more of it for the same muscle-building response, while pointing out that at intakes this high, small differences in protein quality will not have much impact on training gains, and that omnivorous athletes already get more than 40% of their protein from plants [5]. Outside trials, vegans can fall well short: in a 2026 study from Arizona State University of lightly active young women matched for age, weight and body mass index, the vegans ate 44% less protein than the meat-eaters and had 8% less lean mass and 14 to 15% lower leg strength on several measures, though grip strength was similar and a snapshot like this cannot show that the diet caused the gap [17]. The standard allowance for adults, 0.75 to 0.8 g per kilo a day in the UK and the US, is about half the 1.6 g target [3], and the answer on protein covers everyday needs. If you have kidney disease, talk to your kidney team or a dietitian before raising your protein: some people with chronic kidney disease need to keep it moderate, while people on dialysis may need more [9].

What does a vegan day at 1.6 g of protein per kilo look like?

For a 70 kg lifter it can be porridge made with soya milk, a lentil lunch, a soy protein shake after training and tofu with chickpeas for dinner, which come to about 114 g of protein using US Department of Agriculture figures and counting 1 ml of soya milk as 1 g [10].

Meal	What’s in it	Protein
Breakfast	70 g porridge oats made with 300 ml unsweetened soya milk, and 20 g peanut butter	22.3 g
Lunch	200 g cooked lentils and 80 g wholemeal bread	28.0 g
After training	25 g soy protein isolate shaken into 250 ml soya milk	29.2 g
Dinner	150 g firm tofu and 100 g cooked chickpeas	34.8 g
Total		about 114 g

Each meal falls within the IOC’s 0.3 to 0.5 g per kilo, which is 21 to 35 g at 70 kg [7]. Most plant proteins carry less leucine, and the 2021 review lists eating more of them as one way round that, so aiming for the upper end of that range gives a margin, as the dinner here does [5]. Without the protein powder, adding 100 g of tempeh to any meal brings the day back to about 112 g [10]. Check the tofu label, because USDA lists 8.1 g of protein per 100 g for regular calcium-set tofu against 17.3 g for firm [10]. These foods supply only about 1,460 kcal, against the NHS guide of 2,000 kcal a day for an average woman and 2,500 for an average man, which it says varies with how much exercise you do [11], so starchy foods, fruit, vegetables, nuts and oils make up the rest of the day.

What else helps vegans build muscle?

Hard training matters most [8], while among performance supplements creatine has some of the strongest evidence for adding lean mass and strength, and vegans start out with less of it in their muscles. The IOC lists creatine among the few performance supplements with good evidence, with lean mass and strength among its training benefits [7], and the Australian Institute of Sport puts it in its top group, with strong scientific evidence for use in specific situations in sport [14]. The body makes about 1 g of creatine a day and the diet supplies about another 1 g [14], but that dietary gram comes from meat and fish, and a vegan diet supplies almost none [13]. Vegetarians’ muscle creatine has been measured at 90 to 110 mmol per kg of dry muscle, against an average of about 120 for a 70 kg person, according to the International Society of Sports Nutrition’s 2017 position stand, several of whose authors work with supplement companies [12]. A 2020 systematic review of nine studies found that supplementing raised vegetarians’ muscle creatine, often above omnivores’ levels, and increased their lean tissue mass and strength, though the studies carried a moderate to high risk of bias and were mixed on whether it improved vegetarians’ performance more than omnivores’ [13].

The IOC’s protocol is about 20 g a day, split into four doses, for five to seven days, then 3 to 5 g a day, and it warns of a possible 1 to 2 kg of weight gain after loading, mostly water [7]. For under-18s, the ISSN position stand considers creatine acceptable only for young athletes who are in serious, supervised training, eat a well-balanced diet, understand how to use it and stay within recommended doses [12]. Taking 3 g a day from the start fills the muscles more slowly, over about four weeks [12]. Most creatine supplements are made synthetically, without animal products, but capsules may be made of gelatin [13]. Anyone with kidney disease should check with their doctor before taking creatine [12]. It also raises blood creatinine, which can make a standard kidney blood test look worse: a 2026 meta-analysis of 26 trials with 1,036 participants found that creatinine-based estimates of kidney filtration fell by about 11 mL/min while a measure that does not rely on creatinine showed no significant change, which the authors said most likely reflects altered creatinine metabolism, with no sign of kidney injury, so tell your doctor you take it before a kidney test [16]. No controlled study has directly tested creatine alongside prescription medicines, and a 2026 review that found no established interactions of moderate or high severity still advised individual judgement for older people on several medicines, people with kidney disease and anyone taking drugs that can harm the kidneys or are cleared by them, so if you take regular medication, mention creatine to your GP or pharmacist [18]. Competitors in drug-tested sport should know that some supplements contain banned substances as undeclared contaminants, a risk the IOC extends to protein powders, and it says third-party testing schemes reduce that risk without removing it [7]. Vegan athletes covers the rest of a sporting diet.