Can Plant Protein Build Muscle? How Vegan Protein Powders Change The Conversation

Yes, plant protein can build muscle. Muscle growth is driven by total protein intake and essential amino acids, and your body does not care where that comes from; both animal protein and vegan protein can work.

The real question is which delivers the highest amount of quality amino acids in an efficient manner. This is where things get more nuanced. It depends on what type of protein you are talking about, and now that we have plant protein powders, the answer gets murky.

Animal Protein Vs. Plant Protein: What's Different?

Muscle hypertrophy is regulated primarily by increases in muscle protein synthesis (MPS). MPS is stimulated by:

• Adequate total protein intake
• Essential amino acids (EAAs)
• Total BCAAs and leucine per meal
• Resistance training

Leucine acts as a key signaling amino acid that activates mTOR pathways involved in MPS (Stokes et al., 2021). However, leucine alone is not sufficient; all nine essential amino acids must be present in sufficient quantities.

If a protein source is low in EAAs or has reduced digestibility, a larger dose is required to achieve the same anabolic response.

But not all protein is equal. To understand the debate, you need to look at the amino acid profile and digestibility.

1. Amino Acid Profile

Protein is made up of long chains of amino acids; these are the building blocks of muscle.

Animal protein generally has a more optimal amino acid profile:

• High essential amino acid density
• Higher leucine per gram
• Optimized BCAA ratios

Most plant proteins tend to have:

• Lower leucine concentration
• One or more limiting amino acids (e.g., methionine or lysine)
• Lower digestibility in whole-food form

The "leucine trigger" hypothesis suggests that reaching a sufficient leucine threshold maximizes MPS (Stokes et al., 2021). 

This is what makes whey protein a favorite as it's high in leucine and rapidly digested, making it highly effective (Tang et al., 2009).

On the other hand,  some research shows that certain plant proteins may fail to significantly stimulate MPS when intake is not optimized (Arentson-Lantz et al., 2021).

However, this gap shrinks when variables are controlled. When leucine intake is matched, differences between soy and whey largely disappear (Lynch et al., 2020).

2. Digestibility and Protein Quality

Protein must be absorbed to be useful. To score different protein sources, two key scoring systems are used:

• PDCAAS
• DIAAS (more accurate measure of bioavailability)

Animal proteins typically score higher due to:

• Greater digestibility
• Higher indispensable amino acid availability

Plant proteins may contain fiber and antinutritional compounds that reduce absorption, especially in whole-food form.

However, the rise of modern plant protein isolates has virtually eliminated this issue. They improve the digestibility and amino acid concentration of plant protein, which mitigates any differences.

3. Total Protein Intake and Training Context

Perhaps the most important factor concerning protein and muscle growth is total muscle growth. Protein source cannot be evaluated in isolation.

The International Society of Sports Nutrition recommends:

• 1.4–2.0 g/kg/day for active individuals
• Higher intakes during caloric restriction (Jäger et al., 2017)

What This Means Practically:

• If intake is low: higher-quality protein (animal) has an advantage
• If intake is high: differences become minimal

A lifter consuming 1.8–2.2 g/kg/day from well-planned plant sources can build muscle effectively. This was shown in a 2025 meta-analysis:

• Plant protein supports meaningful hypertrophy
• Animal protein shows slightly greater lean mass gains on average (Reid et al., 2025)

Can Plant Protein Build Muscle?

This is where things get more nuanced.

Historically, most protein intake came from whole foods. Protein powders didn't become mainstream until the late 90s–early 2000s—and plant proteins didn't rise until around 2010.

So older arguments were based on whole food comparisons, not modern supplements.

Newer evidence shows plant protein can perform similarly under the right conditions.

1) When Leucine Is Matched

A 12-week study comparing soy vs whey (matched for leucine) found no meaningful differences in muscle growth or strength (Lynch et al., 2020).

This has been seen in other research as well. Again, the amino acids are really what matter.

Takeaway:  If leucine, EAAs, and total protein are matched → results are similar.

2) When Total Protein Intake Is High Enough

Protein supplementation improves muscle and strength gains when paired with quality resistance training (Like our SFS Programs!) For active individuals who are lifting, ISSN guidelines support 1.4–2.0 g/kg/day, with higher intakes during dieting (Jäger et al., 2017).

For plant-based lifters, matching results often requires:

• Higher total protein intake
• Smarter protein selection (soy, pea + rice blends)
• Strategic leucine/EAA support

The Takeaway: Getting high protein from whole plant foods alone can be difficult.

3) When Using Protein Isolates (Not Whole Foods)

This is where most confusion happens, and people talk past each other. 

• Older comparisons looked at: Whole plant foods vs animal protein
• Modern comparisons look at: Plant protein isolate vs whey protein

Once isolated and blended, plant proteins function much closer to animal protein (Santini et al., 2025). Therefore, if you're taking a quality protein powder supplement, you're getting a relatively similar effect.

4) When Used In an Omnivore Diet

Plant protein powders work especially well in mixed diets.

Studies show: Similar benefits when plant protein is added to an omnivore diet.

This is useful for:

• Lifters with lactose intolerance
• Those wanting more variety in protein sources (Santini et al., 2025)

How To Build Muscle With Plant Protein

While animal protein still has an advantage, especially in whole-food form, plant protein can absolutely work.

To maximize results:

• Prioritize soy or pea + rice blends
• Aim for the higher end of protein targets
• Don't underdose post-workout protein

Final Say: Which Is Better For Muscle Growth, Plant Protein or Animal Protein?

This question primarily affects vegans as they may be concerned with their health or progress in the gym. Don't worry.

Thanks to advancements in food production, the clash between protein sources is shrinking. Your body's only concern is a good supply of quality amino acids and protein powders, which makes that extremely easy to do.

And for the meat-eater, if you're looking for another protein source for whatever reason, you can feel confident in knowing that using a quality plant protein powder is a viable option.

SFS has launched our own Protein Powders to support your workouts; plant and whey-based proteins!

• Whey Protein Isolate (Chocolate)
• Whey Protein Isolate (Vanilla)
• Plant Protein Isolate (Vanilla)

FAQ: Animal Protein Vs. Soy Protein

1. Is soy protein "complete"?

Yes. Soy protein is one of the few plant proteins commonly considered complete in practice, and it performs well in training studies. 

2. Do I need more plant protein than animal protein?

Generally yes. Many plant proteins have lower leucine/EAA density and lower digestibility. This means you need to eat either higher grams, better sources, or smart blends.

3. Is animal protein better than plant protein for muscle growth?

Animal protein generally contains higher levels of essential amino acids and leucine per gram, which can stimulate muscle protein synthesis more efficiently. However, plant protein can support muscle growth effectively when total intake and amino acid balance are adequate.

4. Do plant proteins digest differently than animal proteins?

Plant proteins can have slightly lower digestibility due to fiber and naturally occurring compounds. However, modern plant protein isolates improve digestibility and reduce much of this difference.

5. Are plant proteins incomplete?

Most plant proteins are considered "incomplete," meaning at least one essential amino acid has insufficient amounts, not that it's entirely absent. For example, legumes tend to be lower in methionine, while grains are lower in lysine. When combined properly or consumed in sufficient amounts, plant proteins can still meet amino acid needs.

References

1. Arentson-Lantz, E., Von Ruff, Z., Harvey, M., Wacher, A., & Paddon-Jones, D. (2021). A Moderate Serving of a Lower-Quality, Incomplete Protein Does Not Stimulate Skeletal Muscle Protein Synthesis. Current Developments in Nutrition, 5(Suppl 2), 487. https://doi.org/10.1093/cdn/nzab041_002
2. Hoffer, L.J. (2016), Human Protein and Amino Acid Requirements. Journal of Parenteral and Enteral Nutrition, 40: 460-474. https://doi.org/10.1177/0148607115624084
3. Jäger, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., … Antonio, J. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14(1). https://doi.org/10.1186/s12970-017-0177-8
4. Lynch, H. M., Buman, M. P., Dickinson, J. M., Ransdell, L. B., Johnston, C. S., & Wharton, C. M. (2020). No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. International journal of environmental research and public health, 17(11), 3871. https://doi.org/10.3390/ijerph17113871
5. Plotkin, D. L., Delcastillo, K., Van Every, D. W., Tipton, K. D., Aragon, A. A., & Schoenfeld, B. J. (2021). Isolated Leucine and Branched-Chain Amino Acid Supplementation for Enhancing Muscular Strength and Hypertrophy: A Narrative Review. International Journal of Sport Nutrition and Exercise Metabolism, 31(3), 292-301. Retrieved Dec 15, 2025, from https://doi.org/10.1123/ijsnem.2020-0356
6. Reid-McCann, R. J., Brennan, S. F., Ward, N. A., Logan, D., McKinley, M. C., & McEvoy, C. T. (2025). Effect of plant versus animal protein on muscle mass, strength, physical performance, and sarcopenia: A systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews, 83(7), e1581–e1603. https://doi.org/10.1093/nutrit/nuae200
7. Santini, M. H., Erwig Leitão, A., Mazzolani, B. C., Smaira, F. I., de Souza, M. S. C., Santamaria, A., Gualano, B., & Roschel, H. (2025). Similar effects between animal-based and plant-based protein blend as complementary dietary protein on muscle adaptations to resistance training: findings from a randomized clinical trial. Journal of the International Society of Sports Nutrition, 22(1), 2568047. https://doi.org/10.1080/15502783.2025.2568047
8. Stokes, T., Hector, A. J., Morton, R. W., McGlory, C., & Phillips, S. M. (2018). Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients, 10(2), 180. https://doi.org/10.3390/nu10020180
9. Tang, J. E., Moore, D. R., Kujbida, G. W., Tarnopolsky, M. A., & Phillips, S. M. (2009). Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of applied physiology (Bethesda, Md. : 1985), 107(3), 987–992. https://doi.org/10.1152/japplphysiol.00076.2009