Strength
You don’t have to harm animals to be strong
No gapMuscle built on plants vs animal protein in these trials
When protein is matched, vegans build the same muscle and strength as meat-eaters[2][7]. Trials in young lifters[1][3] and older adults[4][5] keep finding the same thing, and pea protein builds muscle as well as whey[6]. You don’t need to harm animals to be strong.
What the evidence says
The main points first. Every claim is tied to a source below.
Vegan and meat-eating lifters built muscle at the same rate in an Illinois trial
Nicholas Burd and Andrew Askow at the University of Illinois randomly assigned 40 young adults to a vegan or an omnivorous diet for nine days of weight training, after a week of getting used to the food[2]. Protein intake was moderate, 1.1–1.2 g per kilogram of body weight[2], which is closer to what people really eat than the huge doses in supplement ads. The participants drank deuterium-labeled water so that newly built muscle protein could be traced, and they gave leg-muscle biopsies at the start and end[2]. Muscle-protein synthesis didn’t differ between the groups[2], and spreading protein evenly across meals made no difference either[2]. Earlier studies of single meals had favored animal protein, but over a whole diet with training, that advantage didn’t show up[2].
Read full article →Long-term vegans gained as much muscle as meat-eaters in 12 weeks
Hevia-Larraín and colleagues in Brazil compared 19 men who had been vegan for at least a year with 19 omnivores, with protein matched at 1.6 g/kg[1]. Both groups lifted weights under supervision twice a week for 12 weeks, and the vegans put on muscle just like the meat-eaters[1]. DXA scans of leg lean mass, ultrasound, muscle biopsies, and 1-rep-max strength tests all showed similar gains in both groups[1].
Read full article →Lifters on a vegan diet gained as much muscle and strength as meat-eaters in 10 weeks
Monteyne’s team first used stable isotopes to measure daily muscle-protein synthesis on a high-protein vegan diet based on mycoprotein and on an omnivorous diet, both at about 1.8 g/kg[1]. The rates matched at rest and after exercise[1]. Then 22 young adults lifted weights five times a week for 10 weeks while eating about 2 g/kg[1]. Lean mass went up 2.6 kg on the omnivorous diet and 3.1 kg on the vegan diet[1], thigh muscle volume rose 8.3% in both groups[1], and muscle-fiber area grew by about a third in both[1]. Strength on several lifts rose by similar amounts[1]. All of it was measured with DXA, MRI, muscle biopsies, and 1RM tests[1], not a bathroom scale.
Read full article →Older adults built muscle protein just as well on a vegan diet
In a 2020 study, Monteyne and colleagues found that older adults built as much muscle protein each day on a mycoprotein-based vegan diet as on an omnivorous diet[1]. In 2024, Domić and colleagues tracked active older men and women for 10 days with an integrated tracer method while they ate about 1.2 g/kg of protein[2]. A well-balanced vegan menu didn’t reduce their mixed-muscle protein synthesis compared with an omnivorous diet with the same calories and protein[2]. Aging muscle still builds on plants as long as there’s enough protein[1][2].
Read full article →Pea protein built as much arm muscle as whey
Babault and colleagues randomly assigned 161 young men to pea protein, whey, or a placebo during 12 weeks of weight training[1]. Among the men who started out weakest, biceps thickness went up 20.2% with pea protein and 15.6% with whey[1]. Strength rose in all three groups, with no clear difference between them[1]. A 2021 review by Lim and colleagues found no clear difference in absolute lean mass or strength between plant and animal protein[2]. The trials were not all matched for the amount of protein, and both groups were generally eating more than the recommended intake[2]. Animal protein still did slightly better on lean mass as a share of body weight, and in adults under 50[2].
Read full article →Articles
Vegan diets build as much muscle as diets with meat
People on vegan diets build as much muscle and strength as meat-eaters when they get the same amount of protein, whether they’re young or older. Trials that measured the muscle directly, with biopsies, MRI scans and strength tests, found no advantage for meat, eggs or dairy, and pea protein did as well as whey.
Read full article →
Sources
Papers and datasets. Each card keeps its caveats, including small samples and single-animal cases.
[1]University of Illinois / MSSE, 2025 · Clinical
Muscle building after lifting was the same on vegan and omnivorous diets
Askow, Burd, and colleagues at the University of Illinois randomly assigned 40 young adults to a vegan or omnivorous diet with 1.1–1.2 g of protein per kg of body weight, and after a week on the diet added nine days of training. They tracked muscle building (myofibrillar protein synthesis) with deuterium-labeled water and leg-muscle biopsies and found no difference between the diets. How the protein was spread across meals didn’t matter either, contrary to the old dogma about protein per meal.
[2]Sports Medicine, 2021 · Clinical
Long-term vegans gained as much muscle as omnivores over 12 weeks of lifting
Hevia-Larraín and colleagues compared 19 men who had been vegan for at least a year with 19 omnivores, all eating 1.6 g of protein per kg and doing supervised resistance training twice a week for 12 weeks. Leg lean mass measured by DXA, ultrasound and biopsy measures of the muscle, and one-rep max strength (1RM) all increased by similar amounts. The protein source didn’t limit their gains.
[3]Journal of Nutrition, 2023 · Clinical
A vegan mycoprotein diet built as much muscle as an omnivorous one over 10 weeks
Monteyne and colleagues found that high-protein vegan and omnivorous diets (about 1.8 g of protein per kg) produced the same daily muscle protein synthesis. Over 10 weeks of high-volume lifting, five sessions a week, at about 2 g/kg, lean mass rose 2.6 kg on the omnivorous diet and 3.1 kg on the vegan diet, thigh volume rose 8.3% in both, and muscle fiber area grew about 33% and 32%, respectively. Strength rose by similar amounts, with results measured by DXA, MRI, biopsies, and 1RM tests.
[4]British Journal of Nutrition, 2020 · Clinical
A vegan mycoprotein diet matched an omnivorous diet for muscle building in older adults
In a randomized trial published in 2020, Monteyne and colleagues found that a high-protein vegan diet based on mycoprotein gave older adults the same daily rate of muscle protein synthesis as an omnivorous diet with the same amount of protein.
[5]Journal of Nutrition, 2024 · Clinical
Active older adults built muscle protein at the same rate on vegan and omnivorous diets
Domić and colleagues fed physically active older men and women vegan or omnivorous diets with the same calories and protein, about 1.2 g of protein per kg. Muscle protein synthesis over the 10 days didn’t differ, so a carefully composed vegan diet didn’t weaken the muscle-building response.
[6]Journal of the International Society of Sports Nutrition, 2015 · Clinical
Pea protein built muscle as well as whey in 161 men over 12 weeks
Babault and colleagues gave 161 men pea protein, whey, or a placebo during 12 weeks of resistance training. Among the men who started out weakest, biceps thickness grew 20.2% with pea protein, 15.6% with whey, and 8.6% with the placebo. Strength rose in all three groups, with no clear difference between them.
[7]Nutrients, 2021 · Review
Plant and animal protein built similar muscle, and the trials were not all matched
Lim and colleagues found no clear difference in absolute lean mass or strength between plant and animal protein. The trials were not all matched for the amount of protein, and both groups were generally eating more than the recommended intake. Animal protein still did slightly better on lean mass as a share of body weight, and in adults under 50.