Macro partitioning
Soy protein supplementation supports muscle growth and strength development comparably to whey protein when both are matched for leucine content during resistance training.
If you are using soy protein to build muscle, ensure your supplement provides about 2-3 grams of leucine per serving (which may require slightly more total soy powder than whey). When matched for this key amino acid, soy supports muscle growth and strength gains just as effectively as whey during resistance training.
These data indicate that increases in lean mass and strength in untrained participants are comparable when strength training and supplementing with soy or whey matched for leucine.
Why this rating
Randomized controlled trial with double-blinding and matched leucine, though limited to untrained individuals.
Source
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
Heidi Lynch et al. · International Journal of Environmental Research and Public Health · 2020
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