Ingredient evidence
Resveratrol and Milk Thistle in Slim Metrix: What the Evidence Really Shows
Neither ingredient has good evidence for weight loss. A 2026 review of 40 trials found resveratrol did not change weight, BMI or fat mass, and NCCIH's milk thistle page does not discuss weight at all. In Slim Metrix, resveratrol is fifth in the 276 mg blend (at most about 55 mg) and milk thistle is third (at most 92 mg).
Written by the Slim Metrix editorial teamUpdated · 9 min read
The question
Why are resveratrol and milk thistle in a weight supplement?
The sales page does not explain their role. Resveratrol is often marketed as a metabolism antioxidant, and milk thistle as liver support.
Slim Metrix lists both inside its 276 mg proprietary blend: milk thistle third of eight, resveratrol fifth. Neither has a printed amount (FDA, Labeling guide ch. IV).
Resveratrol has been tested for weight many times and came up empty. Milk thistle has hardly been tested for weight at all. Neither one changes the picture for a once-a-day capsule.
Blend math
How much resveratrol and milk thistle can one capsule hold?
At most about 55 mg of resveratrol and 92 mg of milk thistle extract. Watch where each sits in the blend.
- 1Alpha-lipoic acid35 to 276 mgListed first: the largest share, at least about 35 mg
- 2Green tea leaf extract (80% catechins, 50% EGCG)0 to 138 mgAt most about 110 mg catechins and 69 mg EGCG
- 3Milk thistle seed extract (80% silymarin)0 to 92 mg
- 4Berberine HCl (97% berberine)0 to 69 mgStudies of weight used 300-1,500 mg a day
- 5Resveratrol (Polygonum cuspidatum root extract 200:1)0 to 55 mg
- 6Cayenne fruit (40,000 H.U.)0 to 46 mgH.U. is a heat rating, not a capsaicin amount
- 7Korean ginseng aerial extract (8% ginsenosides)0 to 39 mg
- 8Banaba leaf extract (2% corosolic acid)0 to 34 mgAt most about 0.69 mg corosolic acid
Blend ingredients are listed from heaviest to lightest (FDA, Labeling guide ch. IV), so the ingredient in place k can weigh at most 276 ÷ k mg. That is our math from the label, not a lab test; the real amounts are probably lower. Zinc (5.5 mg) and chromium (50 mcg) sit outside the blend with their own amounts.
Blend ingredients are listed heaviest first (FDA, Labeling guide ch. IV), so the third can weigh no more than a third of 276 mg. That is our math, not a lab result.
| Ingredient | Label wording | Place in blend | Most it could weigh |
|---|---|---|---|
| Milk thistle | Seed Extract 80% Silymarin | 3 of 8 | 92 mg extract, about 74 mg silymarin |
| Resveratrol | From Polygonum cuspidatum Root Extract 200:1 | 5 of 8 | About 55 mg |
Resveratrol
Does resveratrol help with weight loss?
No good evidence says it does. Shen and colleagues combined 40 placebo-controlled trials, 2,551 people in all, published between 2010 and 2024. Resveratrol had no significant effect on body weight, BMI, fat mass, waist size or hip size (Shen et al., In Vivo 2026).
Some lab markers, such as cholesterol, triglycerides and blood pressure, moved a little. Fasting glucose fell only in short trials and at 100 to 500 mg a day (Shen et al., In Vivo 2026).
Memorial Sloan Kettering calls the metabolic data in obese people inconclusive and found no effect on insulin sensitivity in overweight adults (MSKCC, Resveratrol). One Slim Metrix capsule holds at most about 55 mg. More on the resveratrol ingredient page.
Milk thistle
Is milk thistle good for weight loss?
There is no research to point to. NCCIH's milk thistle page does not discuss weight at all; it is mainly studied for the liver (NCCIH, Milk thistle).
Even the liver evidence is shaky: two NCCIH-funded studies, in hepatitis C and a fatty liver condition called NASH, showed no benefit (NCCIH, Milk thistle).
A few small studies in type 2 diabetes hint at a blood sugar role (NCCIH, Milk thistle). They say nothing about weight.
NCCIH notes that some milk thistle products tested with silymarin amounts different from their labels, or with contaminants (NCCIH, Milk thistle). With a proprietary blend, you cannot see the silymarin amount at all.
The milk thistle page covers the plant, the silymarin standard and the label line in full.
Side by side
Resveratrol vs milk thistle: how does the evidence compare?
| Question | Resveratrol | Milk thistle |
|---|---|---|
| Weight, BMI, fat mass | No effect in 40 trials | Not discussed by NCCIH |
| Blood sugar | Fasting glucose fell only in short trials and at 100 to 500 mg a day | A few small studies in type 2 diabetes |
| Liver | Not its main research area | Conflicting; two NCCIH-funded studies showed no benefit |
| Common side effects | Stomach upset at high doses of 2.5 to 5 g a day | Bloating, nausea, gas |
| Main caution | Blood thinners and drugs cleared by certain liver enzymes | Allergy to ragweed and related plants |
| In Slim Metrix | 5th of 8, at most about 55 mg | 3rd of 8, at most 92 mg |
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Order nowA common belief
Does milk thistle protect the liver from green tea extract?
No source we cite says so. Slim Metrix pairs it with green tea extract, a rare but known cause of liver injury (LiverTox, Green tea). But NCCIH does not describe milk thistle as protection against any supplement's liver effects, and its own liver trials found no clear benefit (NCCIH, Milk thistle).
Treat the green tea warning on its own terms. Dark urine, yellow skin or eyes, or belly pain while taking any green tea extract needs a doctor promptly.
Our green tea extract and liver safety article explains the doses, the gene variant and who is more at risk.
Safety
Who should be careful with resveratrol and milk thistle?
Blood thinners
It may raise bleeding risk with blood thinners and can raise levels of drugs cleared by some liver enzymes (MSKCC, Resveratrol).
Hormone-sensitive cancers
Memorial Sloan Kettering advises caution here (MSKCC, Resveratrol). Ask your care team first.
Ragweed-family allergy
People allergic to ragweed, chrysanthemum, marigold or daisy may react to it (NCCIH, Milk thistle). Little is known about use in pregnancy or breastfeeding.
Slim Metrix also contains berberine, which is not for pregnancy or breastfeeding. Every caution for all ten ingredients is on the side effects page.
Bottom line
Resveratrol and milk thistle: the verdict
Resveratrol did not move the scale in 40 trials. Milk thistle has no weight data. In Slim Metrix they are small shares of a small blend. They are not reasons to buy it.
FAQ
Resveratrol and milk thistle questions
Does resveratrol help you lose belly fat?
No good evidence shows that. A 2026 meta-analysis of 40 placebo-controlled trials found resveratrol had no significant effect on body weight, BMI, fat mass or waist size (Shen et al., In Vivo 2026). Small changes in some blood markers were seen, but the scale and the tape measure did not move.
What is milk thistle used for?
It is mainly sold for liver support, but NCCIH says the liver studies are conflicting or too limited for conclusions (NCCIH, Milk thistle). A few small studies looked at blood sugar in type 2 diabetes. NCCIH's page does not discuss weight, and no weight trial is cited.
Is there enough resveratrol in Slim Metrix to matter?
Probably not for weight, and no amount has been shown to help weight in trials (Shen et al., In Vivo 2026). Resveratrol is fifth in a 276 mg blend, so one capsule holds at most about 55 mg. The clearest fasting glucose change in the 2026 review came at 100 to 500 mg a day.
What are the side effects of milk thistle and resveratrol?
Milk thistle can cause bloating, nausea and gas, and allergic reactions in people sensitive to ragweed or daisies (NCCIH, Milk thistle). Resveratrol causes stomach upset mainly at high doses of 2.5 to 5 g a day, far above one capsule (MSKCC, Resveratrol).
Who should avoid resveratrol supplements?
People on blood thinners or antiplatelet drugs should ask first, because resveratrol may raise bleeding risk and change levels of drugs cleared by liver enzymes (MSKCC, Resveratrol). Memorial Sloan Kettering also advises caution with hormone-sensitive cancers. Show your pharmacist the label.
Do resveratrol and milk thistle lower blood sugar?
The evidence is thin. In a 40-trial review, resveratrol cut fasting glucose only in short trials and at 100 to 500 mg a day (Shen et al., In Vivo 2026). NCCIH cites a few small milk thistle studies in type 2 diabetes (NCCIH, Milk thistle). Neither applies to people whose blood sugar is already normal.
Is resveratrol from Japanese knotweed the same as from grapes?
It is the same compound, a polyphenol also found in grapes, red wine, peanuts and berries (MSKCC, Resveratrol). Slim Metrix uses a Polygonum cuspidatum (Japanese knotweed) root extract labeled 200:1. That ratio describes concentration, not the milligrams of resveratrol in the capsule.
Who wrote this
Written and reviewed by
Plain-language pages built from the label, the sales page and linked public health sources.
Last updated . See our editorial standards and how we check reviews. This website is run by Slimmetrixfit, a licensed U.S. retail desk for Slim Metrix, not by the manufacturer. Orders are processed by BuyGoods on the brand's sales page. Buying through our order links earns us a commission.
Keep reading
More about Slim Metrix
Resveratrol
Fifth in the blend at up to about 55 mg: what a 40-trial review found for weight, and the drug cautions to know.
Read moreMilk thistle
Up to 92 mg of milk thistle extract per capsule: what silymarin is, what liver studies found and the ragweed allergy flag.
Read moreIngredients
All ten ingredients in one place: what each is, the most a capsule can hold, and what research found.
Read moreLicensed U.S. retail desk for Slim Metrix
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