We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Spr6.5
Soy Protein Research
Mostly mechanism / observational
6 peer-reviewed studies
Our research database did not respond in time, so this list covers only our curated studies. It refreshes automatically.
What the evidence says
Mostly mechanism / observational
Most Soy Protein studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 1995–2025 with a typical study size of 266 participants.
Based on 6 studies · 5 meta-analyses · 1 RCT · 1,334 total participants
Confidence
High confidence
By outcome
Muscle strength & powerSupports strength and lean-mass gains with resistance training, comparable to whey over ≥6 weeks · 6-12 weeks
Too few graded studies2 studies
Heart & blood pressureModestly lowers total and LDL cholesterol (FDA-recognized claim) · 4-12 weeks
Too few graded studies1 study
Active research area
3 studies in the last 5 years · Latest meta-analysis: 2025
199520102025
1Male reproductive hormonesMeta-AnalysisCited 45×n=752 · large study2021
In plain English: Sub-analysis of the data according to isoflavone dose and study duration also showed no effect.
Reed KE et al. · Reproductive toxicology (Elmsford, N.Y.) (2021)
Moved here from `red-clover` on 2026-08-24: it is a SOY study and the clinical ruling is that soy-isoflavone evidence does not transfer to red clover.
Sub-analysis of the data according to isoflavone dose and study duration also showed no effect.
This updated and expanded meta-analysis indicates that regardless of dose and study duration, neither soy protein nor isoflavone exposure affects TT, FT, E2 or E1 levels in men.
In plain English: In this meta-analysis we found that the consumption of soy protein rather than animal protein significantly decreased serum concentrations of total cholesterol, LDL cholesterol, and triglycerides without significantly affecting serum HDL cholesterol concentrations.
Anderson JW, Johnstone BM, Cook-Newell ME · N Engl J Med (1995)
38 controlled clinical trials; mean soy intake ~47g/day
In plain English: The results of this meta-analysis indicate that soy protein supplementation produces similar gains in strength and LBM in response to RET as whey protein.
Messina M, Lynch H, Dickinson JM, Reed KE · Int J Sport Nutr Exerc Metab (2018)
Nine studies (266 participants); soy vs whey/animal protein with resistance training ≥6 weeks
No significant between-group difference in strength (bench press, squat) or lean body mass
Soy produces comparable long-term muscle and strength gains to animal protein despite lower leucine
In plain English: Soy-dairy protein blend supplementation during 3 months of resistance training showed a non-significant trend toward greater whole-body lean-mass gain vs placebo; whey alone did not differ from placebo.
Reidy PT, Borack MS, Markofski MM, et al. · J Nutr (2016)
Double-blind RCT in healthy young men: 22g soy-dairy blend vs whey isolate vs carbohydrate placebo, 12 weeks
Strength, muscle thickness, and fiber cross-sectional area increased similarly across all groups
Soy-blend and whey both modestly (non-significantly) enhanced lean-mass gains vs placebo; no strength advantage