Soy Protein
Soy protein is the protein of the soybean, sold as isolates and powders. It is a different component from the isoflavones found in the same bean.
Also listed as Soy Protein Isolate, Soy Protein Powder, Soya Protein, Soya Protein Isolate
How much can LDL cholesterol change?
A 2019 meta-analysis found an average LDL reduction of about 3–4% compared with non-soy protein. The median intake was 25 g soy protein daily over six weeks. This is a modest change in a risk marker, not direct proof that a daily shake prevents heart attacks. 1
Controlled trials show a modest average LDL reduction when soy replaces other protein. 1
The protein and the extract are not interchangeable
An earlier meta-analysis of 23 trials also found improved cholesterol with soy protein containing isoflavones. Tablets of extracted isoflavones did not significantly reduce total cholesterol in that analysis. The result argues against treating every product labeled soy as the same intervention. 2
Soy holds up reasonably well against milk protein
A 2025 review found no pooled difference in muscle-mass outcomes between soy and milk protein across 17 randomized trials. That makes soy a reasonable alternative, without proving that every product or dose is equivalent. Muscle-mass comparisons also do not establish faster recovery from soreness. 3
The cited comparisons concern muscle mass, not recovery from exercise soreness. 3
Effects by health goal
Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.
Cardiovascular1 effect
Women's Hormones2 effects
No study is linked to this rating.
No study is linked to this rating.
Fitness1 effect
No study is linked to this rating.
Bone & Joint1 effect
No study is linked to this rating.
Weight Management1 effect
No study is linked to this rating.
All studies
3 publications are linked to Soy Protein, newest first.