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Ergothioneine

Supplement amino acid general nutritionbrain & mood
Aka: L-ergothioneine, EGT
Brands seen in Singapore: California Gold Nutrition, Life Extension, Toniiq, ProHealth Longevity, Real Mushrooms
Third-party tested: Real Mushrooms certifies other products with NSF Certified for Sport, but nothing for ergothioneine.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
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
Mushroom-derived antioxidant · evidence is associational
Take with
Food · mushrooms are the richest dietary source
Pros & cons
Pros
  • Efsa judged 30 mg/day in adults safe as a supplement
  • Mushrooms are the richest dietary source
Cons
  • Human data is associational, not trial-based
  • Efsa's dose excludes pregnancy and breastfeeding
  • HSA's numeric limits cover vitamins/minerals only
Sources
  1. EFSA NDA Panel — Statement on the safety of synthetic l-ergothioneine as a novel food (EFSA Journal 2017) · read 2026-08-27
    what it says
    “recommended daily dose of up to 30 mg/day for adults excluding pregnant and breastfeeding women and 20 mg/day for children from 3–17 years … The Panel concludes that synthetic l-ergothioneine is safe under the proposed uses and use levels”
  2. Ergothioneine, recent developments (Cheah & Halliwell, Redox Biology 2021) · read 2026-08-27
    what it says
    “the highest dietary levels of ET are found in certain mushrooms … lower blood levels of ET have been associated with incidence of several disorders including Parkinson disease (PD), mild cognitive impairment (MCI), Crohn's disease (CD) and frailty”
  3. HSA — Health Supplements Guidelines (Jan 2026), Tables 4–5 vitamin and mineral limits · read 2026-08-27
    what it says
    “HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5.”
  4. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines (Oct 2025) · 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.”
  5. iHerb Singapore — L-Ergothioneine category page · read 2026-08-27
    what it says
    “L-Ergothioneine: Mushroom Antioxidant Capsules | iHerb”
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Updated 2026-08-30. 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.