Milk Thistle (Silybum marianum)
Of 2,224 on-market milk thistle (silybum marianum) products in the January 2026 DSLD dump, the median declared dose is 173 mg, and 61.3% list unspecified/undisclosed form as the primary form.
Form share
Of 2,193 products with an identifiable primary form, here is the share held by each form of Milk Thistle (Silybum marianum) on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| unspecified/undisclosed form | Unrated | 1,344 | 61.3% |
| Milk thistle seed extract standardized to silymarin (and silymarin/silybin marker rows) | Tier 2 | 822 | 37.5% |
| Silybin-phosphatidylcholine complex (phytosome, e.g. Siliphos) | Tier 1 | 27 | 1.2% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 1,190 products with a disclosed amount.
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- 71.7% of products fall below the fairy-dust threshold (252 mg, 20% of the studied low dose).
- 39.3% of products don't disclose an amount because Milk Thistle (Silybum marianum) is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (mg) to see exactly how it compares to the 1,190 on-market milk thistle (silybum marianum) products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for milk thistle (silybum marianum) on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Label discloses only "Milk Thistle" (often as seed powder) with no silymarin standardization or complex specified.
Typical standardization: Declared as % silymarin (e.g. "80%" appears in raw_form text)
The preparation used in the NASH trials cited on the compound (Legalon, a standardized silymarin preparation), but silybin plasma exposure was lower than that of a silybin-phosphatidylcholine complex in two small human crossover comparisons (see the phytosome form). Rows whose own name is "Silymarin"/"Silybin" are marker-compound mass, not extract mass, so they are recorded without a dose to avoid double counting with the extract row they are nested under.
Source: Barzaghi N et al. 1990, Eur J Drug Metab Pharmacokinet 15(4):333-338, PMID 2088770; Mendez-Sanchez N et al. 2019, BMC Pharmacol Toxicol 20(1):5, PMID 30635055
Compared directly against plain silymarin in healthy volunteers: plasma silybin was much higher after the complex in a 9-subject study (single doses, complex vs silymarin equivalent to 360 mg silybin) and in a separate 23-subject crossover (45 mg complex vs 70 mg silymarin tablets, P<0.0001). Small pharmacokinetic studies in healthy volunteers, not outcome trials; the 2019 paper carries two published errata not reviewed here. The complex's declared mass is not comparable with extract mass, so rows named after it are recorded without a dose.
Source: Barzaghi N et al. 1990, Eur J Drug Metab Pharmacokinet 15(4):333-338, PMID 2088770; Mendez-Sanchez N et al. 2019, BMC Pharmacol Toxicol 20(1):5, PMID 30635055
Reference values
- RDA (adult): not established — Not an essential nutrient; no RDA/AI exists.
- Tolerable Upper Intake Level (adult): not established — Not established. NCCIH (https://www.nccih.nih.gov/health/milk-thistle, fetched) states oral milk thistle appears to be well tolerated, with bloating, nausea and gas the most common side effects, notes possible allergic reactions in people allergic to related plants (ragweed, chrysanthemum, marigold, daisy), and notes concern about product quality: some products have been found to contain silymarin amounts substantially different from the label. It gives no numeric upper limit.
- Studied clinical dose range: 1260–2100 mg
- Navarro VJ et al. 2019, PLoS One 14(9):e0221683, PMID 31536511 -- double-blind placebo- controlled phase II RCT (78 randomized, non-cirrhotic NASH), a standardized silymarin preparation (Legalon) 420 mg or 700 mg three times daily (1260 or 2100 mg/day) for 48 weeks; histologic improvement was 19% (420 mg), 15% (700 mg) and 12% (placebo), not significant, described by the authors as higher than customary doses. Also Wah Kheong C et al. 2017, Clin Gastroenterol Hepatol 15(12):1940-1949, PMID 28419855 -- RCT (n=99, biopsy-proven NASH), silymarin 700 mg three times daily for 48 weeks; the primary endpoint (30% fall in NAFLD activity score) did not differ from placebo (32.7% vs 26.0%, P=.467).
- Note: Unit basis: mg of milk thistle seed (fruit) extract or powder as declared. Labels commonly cite silymarin content (raw_form "Silymarin" is the single most common value and "80%" appears in raw_form text); the trial doses above are mg of silymarin preparation, which is not the same quantity as the extract mass on a label, so the studied range and the fairy-dust threshold are approximate comparators for extract rows and typical consumer extract rows (100-500 mg) will fall below the threshold. Rows named "Silymarin", "Silymarin Flavonoids" or "Silybin" are marker-compound rows (about half are nested under the extract row they describe) and are recorded without a dose to avoid double counting. Trial evidence for liver outcomes is mixed to negative; the NCCIH page reports two NCCIH- funded trials (hepatitis C, NASH) showing no benefit.