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Supplement evidence

069 / 575Protein form

Soy protein

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The short answer

A complete plant protein that supports muscle and can modestly lower LDL when replacing higher-saturated-fat foods.

Evidence and scope
Supported for specific outcomes

This status does not grade the ingredient for every goal, outcome, or person.

Important limitation
Evidence supports a specific outcome, not a general wellness or longevity effect.
Before deciding
Key concern: Soy allergy; separate from levothyroxine and maintain consistent intake.

01 / PRACTICAL GUIDE

Dose, absorption, and combinations

These are indication-specific reference or studied ranges—not a personalized prescription. Start with the objective, then check the form, label, medicines, and health conditions.

Reference range by objective
Per-meal protein25–40 g per serving; about 25 g/day soy protein is used for lipid claims

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source

More is not automatically better. A clinician or product label may specify a different amount.

Absorption / solubilityFat/water classification is not the key factor

Fat/water solubility is not the useful decision point; preparation, fluid, timing, or strain identity matters more.

How it is commonly taken

Use as part of meals or after training.

Do not combine casually

Soy allergy; separate from levothyroxine and maintain consistent intake.

Dose and use source

Dose and use links lead to primary or official source material. Search links are discovery tools, not proof that every returned paper applies.

02 / EVIDENCE

What the research says

We keep supportive, mixed, negative, safety, and contextual findings together. The headline never replaces the underlying papers.

3research papers in this ledger
45unique primary studies represented
124unique participants represented

These are audited counts for this JIVANA collection, not search-result totals. Participants are counted once when multiple papers use the same cohort; review papers are not added again to participant totals.

Open the research timelineResearch timeline

Entries are ordered by publication year. A study period appears only when the source reports it.

2020
Supports a specific usePMID 32486007

No Significant Differences in Muscle Growth and Strength with Leucine-Matched Soy and Whey Protein

Lean mass and strength increased in both groups with no between-source difference; muscle-thickness increase did not reach significance. Matching leucine removed the whey advantage seen in some earlier trials, but there was no no-supplement control.

Study design and methods
Design
Randomized, double-blind, active-comparator trial
Population
61 untrained adults aged 18–35; 48 completed
Intervention
Soy isolate 26 g or whey isolate 19 g, each providing 2 g leucine, during supervised resistance training
Outcome
Lean mass, muscle thickness, and leg-extensor and flexor strength

Funding or conflict note: The authors declared no conflicts and reported that funders had no role in the study or publication decisions.

Open research record
2019
Supports a specific usePMID 31006811 · NCT03468127

A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases LDL and Total Cholesterol

Soy protein lowered LDL by 4.76 mg/dL and total cholesterol by 6.41 mg/dL, about a 3–4% LDL effect. Most individual trials favored soy but only a minority were individually significant; clinical cardiovascular events were not tested.

Study design and methods
Design
Meta-analysis of 43 controlled trials from 46 studies identified by the FDA
Population
Adults with baseline LDL cholesterol of 110–201 mg/dL
Intervention
Soy protein, median 25 g/day, versus non-soy protein
Outcome
LDL and total cholesterol

Funding or conflict note: One author was affiliated with the Soy Nutrition Institute. The abstract did not report an aggregate participant count, so none is inferred.

Open research record
2013
Mixed or qualifiedPMID 24015719

Whey protein supplementation during resistance training augments lean body mass

Lean-mass gain was smaller with soy (1.8 kg) than whey (3.3 kg) and similar to carbohydrate (2.3 kg); fat-mass change did not differ. The result conflicts with later leucine-matched evidence and cannot separate source from leucine or dose differences.

Study design and methods
Design
Randomized, isocaloric three-arm resistance-training trial
Population
63 previously untrained adults
Intervention
Daily soy protein, whey protein, or carbohydrate supplement during supervised training
Outcome
Lean body mass, fat mass, and plasma amino-acid response
Open research record
Unscreened discovery appendix—not evidence2 candidate publicationsSearch run: Aug 21, 2026

Complete for the displayed PubMed query at the search timestamp—not for all databases or every possible synonym. Candidates can be irrelevant, duplicate the same study, or report negative findings. They are never summed as evidence or participants until screened.

03 / SOURCES

Start with the source material

The live search is for discovery only. Search-result counts change and are not included in the audited totals above.

Recent PubMed discovery recordsDirect links to the first 12 records returned by the reproducible search. These are discovery candidates—not reviewed summaries or a count of supportive findings.
  1. Effects of soy protein and resistance exercise on body composition and blood lipids in postmenopausal women.Maesta N, Nahas EA, Nahas-Neto J et al. · 2007 · Maturitas · PMID 17084566Open on PubMed
  2. Effects of soy protein on endothelium-dependent vasodilatation and lipid profile in postmenopausal women with mild hypercholesterolemia.Blum A, Lang N, Vigder F et al. · 2003 · Clinical and investigative medicine. Medecine clinique et experimentale · PMID 12659466Open on PubMed

04 / EXPERT CONTEXT

Expert context—not evidence

Expert positions are dated context—not scientific evidence. They never raise the evidence status or become consensus by repetition.

No direct, source-verified endorsement is currently recorded. Research authorship or discussion alone is not treated as endorsement.

Educational information only—not medical advice. Product quality, dose, medicines, pregnancy, and kidney or liver disease can materially change safety.