Plant vs Animal Protein for Hypertrophy: Do Vegans Build Less Muscle?

Plant vs animal protein for hypertrophy is a smaller gap than most gym talk suggests. When total protein is high enough and training is hard, vegan and omnivore lifters have gained similar muscle and strength in the trials run so far. Single plant proteins do look weaker in a lab, which is why the details of your day matter.

This article is the head-to-head review. For the bigger picture of protein types, doses and timing, start with our complete protein guide for hypertrophy. Here we stay on one question: does the source change the result?

Can vegans build as much muscle as meat eaters?

The two best direct comparisons say yes, with caveats.

In 2021, researchers recruited 19 habitual vegans and 19 omnivores, all young men, and had them train twice a week for 12 weeks. Everyone’s protein was topped up to 1.6 g/kg/day, with soy protein for the vegans and whey for the omnivores. Leg lean mass rose by 1.2 kg in both groups, and muscle fibre size, whole-muscle size and leg-press strength improved with no significant difference between them (Hevia-Larraín et al., 2021). The participants were untrained men, so we cannot stretch this to advanced lifters.

In 2023, a second trial split 22 young adults (11 men, 11 women) into a vegan or an omnivorous diet at about 2 g/kg/day for 10 weeks of high-volume training, five days a week. Lean mass rose by 3.1 kg (vegan) and 2.6 kg (omnivore), thigh muscle volume rose 8.3% in both, and the groups did not differ statistically (Monteyne et al., 2023). The vegan diet in that study leaned on mycoprotein, which is hard to find in India, so the result is encouraging rather than a recipe.

Why do plant proteins look weaker in the lab?

There is a real reason the myth exists. A review of acute studies explains that soy and wheat protein produced a lower muscle protein synthesis response than several animal proteins. Proposed reasons include lower digestibility, more of the amino acids being diverted to urea production, and lower content of certain essential amino acids, along with lower leucine in most plant proteins (van Vliet et al., 2015).

In plain gym language:

• Leucine is the amino acid that acts like a switch for muscle protein synthesis. Most plant proteins contain less of it per gram. (We cover the trigger idea in the leucine threshold article.)
• Lysine and methionine are often the limiting amino acids in single plant foods, with cereals usually lower in lysine and legumes lower in methionine.
• Digestibility is lower for many plant proteins, partly due to fibre and other compounds in the food. How scores like DIAAS compare is in protein quality scores explained.

Those same authors list ways to close the gap: eat larger amounts of plant protein, combine several plant sources, or fortify with the limiting amino acids. They also state that these strategies still needed testing (van Vliet et al., 2015). That is a theory-based fix, so treat any exact “add 10-20%” number you see online with caution.

Soy vs whey protein muscle growth

Soy is the most studied plant protein in this area, so it gives the cleanest comparison.

A meta-analysis pooled 9 studies with 266 participants that supplemented resistance training with soy or animal protein (whey in five, others beef, milk or dairy protein). Strength and lean mass rose, with no difference between soy and animal protein for bench press, squat or lean mass (Messina et al., 2018).

A 12-week randomized trial matched soy and whey for leucine (2 g in each serving, which meant 26 g of soy isolate versus 19 g of whey isolate). Among 48 untrained adults who finished, lean mass rose about 1.5 kg and strength improved in both, with no group difference (Lynch et al., 2020).

A 2026 systematic review of untrained adults also found no significant lean mass difference between plant (soy and pea) and whey supplements. Its authors cautioned that only 5 studies qualified and confidence intervals were wide, so it does not prove the two are identical (Callegari et al., 2026).

Fear about soy and hormones is a separate question, covered in soy protein and testosterone myths.

Plant protein amino acid profile: do you need to combine foods?

You do not need to be anxious about it. You do need variety.

A plant food is “incomplete” only in the sense that one or two essential amino acids are relatively low, not absent. If your day includes roti or rice, dal, some soya or dairy, and a few other foods, the gaps tend to fill each other. There is no strong evidence that this has to happen inside a single meal when total intake is adequate, though that is a reasonable inference rather than something every trial has tested.

Blends also work in studies. In 33 resistance-trained young adults, 25 g of pea protein, mycoprotein or a blend of the two all raised post-exercise muscle protein synthesis to a similar degree, even though pea is often called low in methionine (West et al., 2023). That was a short acute study, not hypertrophy over months. For blend products, see vegan protein powder blends.

Plant vs animal protein: quick comparison

Question	Plant sources (single)	Animal sources	What to do
Leucine per gram	Usually lower	Usually higher	Slightly larger servings
Limiting amino acid	Lysine (cereals), methionine (legumes)	Rarely limiting	Mix grains, legumes, soya
Digestibility	Often lower	Often higher	Cook well, vary sources
Long-term training results	Similar when protein matched	Similar when protein matched	Hit your total target
Practical risk	Falling short on total protein	Less common	Track intake for 1-2 weeks

What the older-adult trial warns us about

Not every result is reassuring, and it would be dishonest to skip this one. In a 2026 randomized trial, 72 adults aged 65 or older followed a self-selected vegan diet, their habitual omnivorous diet, or a vegan diet plus resistance exercise for 12 weeks. The vegan group’s protein intake fell by roughly 19-28 g/day depending on the week, and thigh muscle volume (-0.61 L) and appendicular lean mass (-1.15 kg) dropped relative to the omnivore group, whose measures were stable. The vegan-with-exercise group lost less (Domić et al., 2026).

The trial’s own conclusion pointed to lower protein intake as part of the story. The takeaway is not “vegan diets cost muscle.” It is that when people switch without planning, protein drops, and older muscle is less forgiving. If you are older, on medication, or have kidney or other medical conditions, speak to your doctor or a registered dietitian before changing protein intake.

How to make plant-based protein work for lifting

1. Set your target first. Use the protein calculator and aim for roughly 1.6-2.0 g/kg/day, the range used in the trials above. For a 70 kg lifter, that is about 112-140 g.
2. Build 3-4 protein feeds a day. Examples: paneer or tofu bhurji, soya chunk curry, curd with chana, dal with rice, a soy or pea shake.
3. Choose bigger portions of lower-leucine foods. Dal and rice is fine, but double the dal.
4. Vary across the day. Grains, legumes, soya and nuts or seeds in the same day beats eating one source on repeat.
5. Use powder as a gap-filler. A soy or pea-rice powder is a cheaper route than another 200 g of paneer when budget is tight. Look for third-party testing.
6. Review in 8-12 weeks. If strength and waist or limb measurements are not moving, raise calories and protein before changing sources.

For a full-day vegetarian layout, our free diet plan is a starting point, and the general numbers sit in the optimal daily protein intake review.

What we still do not know

• The big trials are small (under 40 people) and short (10-12 weeks).
• Most participants were young and either untrained or moderately trained, so advanced lifters on a vegan diet are under-studied.
• Several studies used soy or mycoprotein, which may not match what you actually eat daily.
• The best exact “extra plant protein” amount has not been tested, and I would not trust a precise figure from anyone yet.

The bottom line

Plant vs animal protein for hypertrophy comes down to total protein, training quality and consistency. Plant sources have a lower per-gram amino acid profile, but when people who lift eat enough protein from varied sources, muscle and strength gains have looked similar. If you are vegetarian or vegan, count your protein, lean on soya, dal, dairy (if you eat it) and a decent powder, and keep lifting progressively.