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Milk thistle

Supplement botanical gutgeneral nutrition
Aka: silymarin, Silybum marianum
Brands seen in Singapore: California Gold Nutrition, NOW Foods, Thorne, Swanson Vitamins, Life Extension
Third-party tested: Thorne certifies other products with NSF Certified for Sport, but nothing for milk thistle.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
Ast and alt fell in pooled trials · liver results conflict
Studied for
2 months or less is where the bigger enzyme drops sat
Pros & cons
Pros
  • 55 randomised trials, 3,545 patients pooled
  • Ast and alt both fell significantly
  • NCCIH: taken orally, appears to be well tolerated
Cons
  • NCCIH: liver trial results conflict or are limited
  • Bloating, nausea and gas are the common side effects
  • No significant effect on alp; no dose–effect link found
Sources
  1. NCCIH — Milk Thistle (what the science says: liver disease) · read 2026-08-27
    what it says
    “Results from clinical trials of milk thistle for liver diseases, such as alcohol-related liver disease, hepatitis B and C, non-alcoholic fatty liver disease … have been conflicting or too limited to allow conclusions to be reached”
  2. NCCIH — Milk Thistle (overall strength of evidence) · read 2026-08-27
    what it says
    “There isn't enough high-quality evidence to allow definite conclusions to be reached about the effects of milk thistle on health conditions in people”
  3. NCCIH — Milk Thistle (safety and side effects) · read 2026-08-27
    what it says
    “Milk thistle, when taken orally, appears to be well tolerated. The most common side effects are digestive symptoms such as bloating, nausea, and gas”
  4. NCCIH — Milk Thistle (allergy caution) · read 2026-08-27
    what it says
    “Milk thistle may cause allergic reactions, particularly among people who are allergic to related plants (for example, ragweed, chrysanthemum, marigold, and daisy)”
  5. NCCIH — Milk Thistle (pregnancy and breastfeeding) · read 2026-08-27
    what it says
    “Little is known about whether it's safe to use milk thistle during pregnancy or while breastfeeding”
  6. NCCIH — Milk Thistle (medicines) · read 2026-08-27
    what it says
    “If you take any type of medicine, talk with your health care provider before using milk thistle or other herbal products; some herbs and medicines interact in harmful ways”
  7. NCCIH — Milk Thistle (blood sugar; NOT used in user-facing copy — see verify_notes) · read 2026-08-27
    what it says
    “Results from a small number of studies in people show that milk thistle extracts may help to control blood sugar in people with type 2 diabetes”
  8. Are alterations needed in Silybum marianum (Silymarin) administration practices? Meta-analysis of randomized trials targeting liver injury (BMC Complement Med Ther 2025) · read 2026-08-27
    what it says
    “55 studies with a total of 3545 patients were included … silymarin administration showed a significant reduction in AST … and ALT … levels. While it had no statistically significant effect on ALP level”
  9. Silymarin meta-analysis 2025 — dose and duration subgroups · read 2026-08-27
    what it says
    “Silymarin at a dose of less than 400 mg and treatment duration ≤ 2 months showed greater decreasing effects on AST and ALT levels compared to its high doses and longer treatment duration”
  10. Silymarin meta-analysis 2025 — meta-regression and BMI subgroup · read 2026-08-27
    what it says
    “no significant association between dose, age, BMI, treatment duration and hepatoprotective effects of silymarin … no significant effects on AST and ALT levels in patients with BMI ≥ 30”
  11. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (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 [milk thistle / silymarin not listed in Annex A or B]”
  12. iHerb Singapore — Herbs > Milk Thistle (Silymarin) category (default order) · read 2026-08-27
    what it says
    “California Gold Nutrition, Silymarin Complex, 120 Veggie Capsules … NOW Foods, Milk Thistle Extract, 300 mg … Thorne, S.A.T.®, 60 Capsules … Swanson Vitamins, Full Spectrum® Milk Thistle, 500 mg … Life Extension, Advanced Milk Thistle”
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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.