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Soy protein

Supplement protein fitnesswomen's health
Aka: soy protein isolate
Brands seen in Singapore: NOW Foods, Naturade, Nutricost, MHP
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Daily protein · a small cholesterol shift vs other protein
When to take
Pre- or post-workout both count in ISSN's protein stand
Take with
Varied protein sources — soy is short on methionine
Pros & cons
Pros
  • NCCIH: may lower cholesterol a little vs other protein
  • NCCIH: may ease menopausal hot flushes — effect small
  • ISSN: soy raised mps more than casein at rest
Cons
  • ISSN: rated a lower-quality complete protein
  • 12 weeks: milk protein beat soy for lean mass
  • NCCIH: some people are allergic to soy
Sources
  1. NIH NCCIH — Soy (health topic page) · read 2026-08-27
    what it says
    “Consuming soy protein in place of other proteins may lower cholesterol levels to a small extent. Soy isoflavones may not have the same effect”
  2. NIH NCCIH — Soy, menopausal symptoms · read 2026-08-27
    what it says
    “Soy isoflavone supplements or soy protein may help to reduce the frequency and severity of menopausal hot flashes, but the effect may be small, and research results have not been completely consistent”
  3. NIH NCCIH — Soy, breast cancer · read 2026-08-27
    what it says
    “Soy products in supplement form have not been shown to reduce breast cancer risk”
  4. NIH NCCIH — Soy, safety · read 2026-08-27
    what it says
    “Some people are allergic to soy. In the United States, the presence of soy in packaged foods and dietary supplements must be indicated on the product label”
  5. NIH NCCIH — Soy, duration of use studied · read 2026-08-27
    what it says
    “In research studies, soy protein supplements have been safely used for up to 16 weeks, and soy extracts containing concentrated isoflavones have been used safely for up to 6 months”
  6. NIH NCCIH — Soy, pregnancy · read 2026-08-27
    what it says
    “The use of soy during pregnancy may be unsafe in amounts greater than those commonly found in foods”
  7. NIH NCCIH — Soy, interactions · read 2026-08-27
    what it says
    “Interactions between certain soy products containing high amounts of tyramine (such as tofu and soy sauce), and monoamine oxidase inhibitors (a group of antidepressant drugs) have been reported”
  8. NIH ODS — Exercise and Athletic Performance (HP), protein implications for use · read 2026-08-27
    what it says
    “Soy protein lacks the EAA methionine and might lose some cysteine and lysine in processing; rice protein lacks the EAA isoleucine”
  9. NIH ODS — Dietary Supplements for Exercise and Athletic Performance (Health Professional), protein safety (updated 1 Apr 2024) · read 2026-08-27
    what it says
    “The Food and Nutrition Board has not set a UL for protein, noting that the risk of adverse effects from excess protein from food is very low”
  10. ISSN position stand: protein and exercise (Jäger et al., JISSN 2017) — protein quality · read 2026-08-27
    what it says
    “Research has shown that soy is considered a lower quality complete protein”
  11. Jäger et al., JISSN 2017 — Hartman et al., 12 weeks milk vs soy · read 2026-08-27
    what it says
    “They found that the participants that consumed the milk protein increased lean mass and decreased fat mass more than the control and soy groups”
  12. Jäger et al., JISSN 2017 — Tang et al. comparison of whey, soy and micellar casein · read 2026-08-27
    what it says
    “These authors reported that the ability of soy to stimulate MPS was greater than casein, but less than whey, at rest and in response to an acute resistance exercise stimulus”
  13. Jäger et al., JISSN 2017 — position statement on timing · read 2026-08-27
    what it says
    “The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion”
  14. FDA — Daily Value on the Nutrition and Supplement Facts Labels, Reference Guide: Daily Values for Nutrients (content current as of 03/05/2024) · read 2026-08-27
    what it says
    “DVs are the recommended amounts of nutrients to consume or not to exceed each day … Protein | 50g”
  15. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (Oct 2025), Annexes A/B · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list”
  16. iHerb Singapore — Soy Protein category page, default sort · read 2026-08-27
    what it says
    “Soy Protein | iHerb … 1 - 9 of 9 results”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.