Soy Protein: Heart Claim, Cholesterol and Muscle
App Library Tools Pricing Download
[Supplement · Compound guide]

Soy Protein: half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is soy protein?

Soy protein is protein from soybeans, used in foods and protein powders. It is known for an FDA-authorized heart health claim on food labels, which FDA proposed revoking in 2017.

Also known as: soy protein isolate, isolated soy protein, soya protein.

Amounts studied

The FDA health claim applies to foods with soy protein and refers to 25 g of soy protein a day as part of a diet low in saturated fat and cholesterol (21 CFR 101.82). The cholesterol meta-analysis below covered a median of 25 g a day for a median of 6 weeks (Blanco Mejia 2019). These are study protocols, not a recommendation.

Approval status and how it is used

It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.

The FDA heart claim: under 21 CFR 101.82, qualifying foods may say that 25 g of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. In October 2017 FDA proposed revoking this claim, saying its review tentatively found the evidence no longer shows significant scientific agreement (Federal Register). As of the October 2026 eCFR, the regulation is still in place.

What studies show: a meta-analysis of 43 of the 46 trials FDA identified in that review found soy protein lowered LDL cholesterol by about 4.8 mg/dL and total cholesterol by about 6.4 mg/dL compared with other proteins, roughly 3% to 4%; one author is from the Soy Nutrition Institute (Blanco Mejia 2019). For muscle, a meta-analysis of 9 studies (266 people) found soy protein gave similar gains in strength and lean mass with resistance training as whey or other animal proteins (Messina 2018).

Safety: the sources here do not describe side effects or drug interactions.

Soy protein half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a single published half-life or time to peak for soy protein that applies to a supplement dose, so we do not list one. Protein is digested into amino acids, so no single figure describes it.

How to track soy protein in Dose Track

  1. Add soy protein as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each serving when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

Soy Isoflavonessoy, genistein Pea Proteinpea protein isolate, Pisum sativum protein Whey Proteinwhey protein isolate, whey concentrate Plant Sterols and Stanolsphytosterols, plant stanols

Frequently asked questions

What is the half-life of soy protein?+
We could not find a single published half-life or time to peak for soy protein that applies to a supplement dose, so we do not list one. Protein is digested into amino acids, so no single figure describes it.
Does soy protein lower cholesterol?+
Modestly. A meta-analysis of the trials FDA reviewed found about 3% to 4% lower LDL cholesterol, at a median of 25 g a day. FDA proposed revoking its soy heart claim in 2017, but the regulation was still in place as of October 2026.
Is soy protein as good as whey for muscle?+
A meta-analysis of 9 studies found similar gains in strength and lean mass with soy or animal protein during resistance training.
Can I track soy protein in Dose Track?+
Yes. Soy protein is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each serving next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Code of Federal Regulations, 21 CFR 101.82. Health claims: soy protein and risk of coronary heart disease (eCFR, accessed October 28, 2026).
  2. FDA. Food labeling: health claims; soy protein and coronary heart disease. Proposed rule. Federal Register, October 31, 2017.
  3. Blanco Mejia S, et al. A meta-analysis of 46 studies identified by the FDA demonstrates that soy protein decreases circulating LDL and total cholesterol concentrations in adults. J Nutr. 2019;149(6):968-981.
  4. Messina M, et al. No difference between the effects of supplementing with soy protein versus animal protein on gains in muscle mass and strength in response to resistance exercise. Int J Sport Nutr Exerc Metab. 2018;28(6).
  5. FDA. Questions and answers on dietary supplements.

All compound guides · Reconstitution calculator · Supported medications