Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Soy Protein

What does the research say about Soy Protein?

4 health outcomes synthesised

Soy protein has been studied across 4 health outcomes, with the strongest evidence supporting its role in reducing blood cholesterol (8 studies, moderate evidence) and improving walking speed (3 studies, moderate evidence). Effective doses for cholesterol reduction typically range from 20–40 g/day, and benefits are most consistently observed in clinical populations such as individuals with chronic kidney disease or type 2 diabetic nephropathy.

Strongest evidence: Soy protein shows moderate evidence for reducing blood cholesterol, with 5 of 8 studies reporting beneficial effects at doses of 20–40 g/day over 90–180 days in clinical populations. Moderate evidence also supports improved walking speed, with all 3 studies showing benefits in elderly or pre-frail/frail adults over 8–12 weeks, though effective doses were not consistently reported.

Mixed or weaker evidence: Evidence for reducing LDL cholesterol is low (3 studies; 2 beneficial, 1 neutral), with one RCT finding no effect at 40 g/day over 90 days. Evidence for reducing C-reactive protein (CRP) levels is also low (3 studies; 1 beneficial, 2 neutral), with benefits limited to adults with chronic inflammatory diseases.

Effective dose patterns: For cholesterol outcomes, studies converge on 20–40 g/day of soy protein. The LDL cholesterol synthesis suggests a higher dose of approximately 40 g/day (35% of diet), but this was contradicted by a neutral RCT at the same dose.

Population insights: Cholesterol benefits are most consistent in clinical populations (chronic kidney disease, diabetic nephropathy, postmenopausal women). Walking speed improvements are specific to elderly or pre-frail/frail populations. CRP reductions may be limited to those with chronic inflammatory conditions.

Notable caveats: Publication bias is a concern across multiple syntheses (null results less likely published). Many studies lack adequate dose reporting. The evidence base is small for walking speed, LDL cholesterol, and CRP (3 studies each). One beneficial LDL study analyzed soy protein as part of a broader dietary pattern, not as a standalone supplement.

Frequently asked

  • What is Soy Protein good for according to research?
    Research shows moderate evidence that soy protein can help reduce blood cholesterol (5 of 8 studies) and improve walking speed (3 of 3 studies). Low evidence suggests possible benefits for reducing LDL cholesterol and C-reactive protein levels in specific populations.
  • What dose of Soy Protein is typically used in studies?
    For blood cholesterol reduction, doses typically range from 20–40 g/day. For LDL cholesterol, one study used approximately 40 g/day (35% of diet). Doses were not consistently reported across walking speed and CRP studies.
  • Who benefits most from Soy Protein?
    Cholesterol-lowering benefits are most consistently observed in clinical populations such as individuals with chronic kidney disease, type 2 diabetic nephropathy, and postmenopausal women. Walking speed improvements are seen in elderly and pre-frail/frail older adults. CRP reductions may benefit those with chronic inflammatory diseases.
  • Are there caveats or limitations in the research on Soy Protein?
    Yes. Publication bias is a concern across multiple outcomes—null-result studies are less likely to be published. Many studies lack adequate dose reporting. For three of four outcomes, the evidence base is small (3 studies each). One beneficial LDL study analyzed soy protein as part of a broader diet, not as a standalone supplement.
  • Does Soy Protein help with reducing blood cholesterol?
    Moderate evidence from 8 studies shows that soy protein can produce small to moderate reductions in blood cholesterol, with 5 studies reporting beneficial effects and 3 showing no significant effect. Benefits are most consistent in clinical populations at doses of 20–40 g/day over 90–180 days.
  • Does Soy Protein help with reducing C-reactive protein (CRP) levels?
    Low evidence from 3 studies shows mixed results: 1 meta-analysis found moderate reductions in CRP in adults with chronic inflammatory diseases, while 2 studies found no significant effect in other populations. The evidence is preliminary and limited to specific subgroups.

Most-studied combinations with Soy Protein

most supplement research is combination research
Also studied with:Casein Protein (4), Whey Protein (4), Milk Protein (3), Soy (3)

  • Phytoestrogen with Wild Yam

    By Solaray

    5 (26 reviews)
    In Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $24.00
    		In
    Vitacost
    $24.00
    		In
    Vitamin Shoppe
    $-
    		Out

  • Testralin

    By Metagenics

    5 (2 reviews)
    In Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $82.78
    		In
    Vitacost
    $-
    		Out
    Vitamin Shoppe
    $-
    		Out

  • Beyond Red Yeast Rice

    By Kal

    4.5 (8 reviews)
    Out of Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $26.99
    		In
    Vitacost
    $26.99
    		In
    Vitamin Shoppe
    $-
    		Out

  • Weight Gain, Vanilla

    By Naturade

    Out of Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $37.16
    		In
    Vitacost
    $-
    		Out
    Vitamin Shoppe
    $-
    		Out

  • Men's 40+ Multi

    By Ancient Nutrition

    4.6 (40 reviews)
    In Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $42.46
    		In
    Vitacost
    $42.46
    		In
    Vitamin Shoppe
    $-
    		Out

  • Protein Pretzels

    By WonderSlim

    Out of Stock
    Available From
    Available From
    MerchantPriceStockAction
    Amazon
    $-
    		Out
    iHerb
    $12.43
    		In
    Vitacost
    $-
    		Out
    Vitamin Shoppe
    $-
    		Out
Back to top