Verified
“Guaranteed 80% silymarin (280 mg per capsule)”
The label carries a guaranteed-potency claim of 80% silymarin, computing to 280 mg per 350 mg capsule — a guarantee rather than a labeled minimum.
Reviewed
Verified by SAC team
+20
XP on completion
Best One-a-Day
Solaray
Solaray Milk Thistle Seed Extract 350 mg, One Daily, Guaranteed 80% Silymarin, 60 VegCaps Review
7.2/10SAC Product Score™
The easiest one-and-done pick. A single vegan capsule delivers 280 mg of silymarin from a guaranteed-potency 80% extract — the most silymarin per capsule of any plain extract here — so adherence is effortless. Two caveats keep it mid-pack: it's still plain extract with no absorption enhancement, and even 280 mg sits a touch under the classic ~420 mg trial dose.
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Read the complete Milk Thistle (Silymarin) guide →How we built the SAC Product Score™ — 7.2/10
Form & Bioavailability30%6.5/10
Plain milk thistle seed extract standardized to 80% silymarin — no phytosome, so the ordinary absorption ceiling applies. Solid, straightforward form with no delivery enhancement.
Silymarin/Silybin Dose vs Clinical Range25%8/10
280 mg silymarin in one capsule is the highest single-cap dose among the plain extracts, and 'guaranteed 80%' means the potency is assured, not just labeled. It still lands a bit under the ~420 mg used in several trials.
Third-Party Testing & Quality Assurance20%6.5/10
Tested in Solaray's own Utah lab with a guaranteed-potency label — better than a bare labeled minimum — but there's no independent NSF or USP seal, so it stays mid-tier here.
Value per Effective Serving15%7.5/10
At ~$18 for 60 one-a-day servings (~$0.30 each), value is good given the high single-cap dose, though a 60-count bottle is smaller than the big-bottle value picks.
Formulation Suitability & Tolerability10%8.5/10
Vegan VegCaps and a convenient once-daily format — an adherence-friendly, broadly tolerable profile.
The product at a glance
- Form
- Milk thistle seed extract, guaranteed 80% silymarin (veg cap)
- Silymarin load
- 280 mg silymarin per capsule
- Supply
- 60 VegCaps = 60 servings (one daily)
- Testing
- Brand lab, guaranteed-potency label
- Suitability
- Vegan
- Price
- ~$18
- Cost per serving
- ~$0.30/serving (1 cap)
Marketing claims vs. reality
Verified
“One-a-day dosing”
The product is formulated and labeled for once-daily use, and the 280 mg single-cap dose supports that positioning.
Partial
“Tested in Solaray's own lab”
Testing is performed in Solaray's Utah lab per the brand, but this is in-house/brand-stated rather than an independent NSF or USP certification.
Partial
“Supports healthy liver function”
Even at 280 mg the dose is below the ~420 mg used in trials, and high-quality studies (Rambaldi 2005) found no confirmed benefit, so the claim is only partly supported.
What our test actually found
01Adherence is the advantage
The single biggest predictor of a supplement working is taking it. A genuine one-a-day at 280 mg removes the friction of multi-cap regimens, which is a real, underrated edge over higher-count bottles you have to dose 2–4 times.
02'Guaranteed' beats 'labeled'
A guaranteed-potency claim means the 80% is assured through shelf life, not just a manufacturing target. On the dose axis that's a meaningful step up from a bare labeled minimum.
03Still short of the trial dose
280 mg is the most per single cap among plain extracts, but several liver studies used ~420 mg/day. If you want to match that exactly, you'd double up — which erodes the one-a-day appeal.
04Standard absorption, in-house testing
It's plain extract, so take it with food, and the testing is Solaray's own lab rather than an independent seal. Those two points, not the dose, are what hold it at #6.
Pros & cons, no sugar-coating
Pros
- Highest single-capsule silymarin of the plain extracts — 280 mg, one a day
- Guaranteed (not just labeled) 80% potency
- Convenient once-daily dosing, vegan caps
- Tested in Solaray's own Utah lab (brand-stated)
Cons
- Plain extract — no absorption enhancement
- 280 mg/day still sits below the ~420 mg used in several liver studies
- Smaller 60-count bottle; no independent NSF/USP seal
The easiest one-and-done
The easiest one-and-done pick — a single vegan capsule delivers the most silymarin per cap of any plain extract here, with a guaranteed-potency label. Two caveats keep it mid-pack: it's still plain extract, and even at 280 mg you're a touch under the classic trial dose. If a single daily capsule is what gets you to actually take it, that adherence edge is worth a lot.
Check Solaray on AmazonIf this doesn’t fit — try these
Nutricost Milk Thistle 300 mg
7.5/10Cheaper per milligram if you don't mind taking two capsules to hit the dose.
See it on the list →Life Extension Advanced Milk Thistle
8.4/10A clinical-range dose plus phytosome absorption if you want to clear ~420 mg in one serving.
See it on the list →Pure Encapsulations Silymarin
7.8/10A hypoallergenic single-ingredient extract with a stronger testing reputation.
See it on the list →Sources & further reading
- Rambaldi A, Jacobs BP, Iaquinto G, Gluud C. Milk thistle for alcoholic and/or hepatitis B or C liver diseases—a systematic review with meta-analyses. Am J Gastroenterol. 2005;100(11):2583-2591.Rambaldi A, Jacobs BP, Iaquinto G, Gluud C · 2005 · American Journal of Gastroenterology · PMID 16279916
Milk thistle for alcoholic and/or hepatitis B or C liver diseases—a systematic review with meta-analyses of randomized clinical trials
No significant benefit on mortality or complications was seen in high-quality trials.
- Gillessen A, Schmidt HH. Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review. Adv Ther. 2020;37(4):1279-1301.Gillessen A, Schmidt HH · 2020 · Advances in Therapy · PMID 32065376
Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review
Reports favorable supportive effects at a lower evidence tier than controlled trials.