Guide
How much resveratrol should you take a day?
There is no established daily value for resveratrol. Trials used 25 mg up to 5 g a day; a '600 mg' capsule may hold far less actual resveratrol than the number suggests.
There is no established daily amount of resveratrol: supplement labels print "Daily Value not established", and trials have used anything from 25 mg to 5 g a day. Our capsule label directs one capsule twice a day. That is 1,200 mg of root complex a day, which the label's 50% figure puts at about 600 mg of trans-resveratrol.
What our label directs
Each Electric Tiger Resveratrol capsule contains 600 mg of Japanese knotweed root complex, labelled as containing 50% trans-resveratrol. Directions: take one capsule twice a day, 20 to 30 minutes before a meal, or as directed by your healthcare professional. Do not exceed the recommended dose. The Supplement Facts panel prints a serving size of one capsule and 60 servings; at two capsules a day a 60-capsule bottle lasts 30 days. It is as low as $15.83 a bottle on subscription, which works out to about $0.53 a day at two capsules (our arithmetic). See the product page for every option.
Resveratrol 500 mg, 600 mg, 1,000 mg: reading the number
The number on the front is not always the amount of resveratrol. Two examples:
| Label says | What to check | Trans-resveratrol per capsule |
|---|---|---|
| "600 mg complex containing 50% trans-resveratrol" | 600 x 0.50 | About 300 mg (by the label's 50%; no COA) |
| "500 mg resveratrol" | Is it extract or trans-resveratrol? Is a percentage printed? | Unknown until the panel says |
| "1,800 mg complex, 50% trans, per 3 capsules" | 1,800 x 0.50, then divide by capsules | About 900 mg per serving |
On our label the 600 mg is the weight of the complex, not of resveratrol, and the panel does not say what the other half is. The 50% figure is the label's statement; we hold no certificate of analysis, so treat about 300 mg as arithmetic, not a measurement.
What doses have researchers used?
Published human studies span a very wide range. A radiolabelled absorption study used 25 mg once. Randomized trials have used 75 mg a day for 12 weeks, 150 mg a day for 30 days and 200 mg a day for 26 weeks. A study of drug-metabolising enzymes used 1,000 mg a day for 4 weeks. A 29-day study in 40 healthy volunteers gave 0.5, 1, 2.5 or 5 g a day; the authors called resveratrol safe, but the 2.5 and 5 g doses caused mild to moderate gastrointestinal symptoms.
By the label's arithmetic our directions come to about 600 mg of trans-resveratrol a day. That sits above most of the low-dose trials and below the 1 g and higher ones, and we know of no trial run at that dose. So we do not tell you what 600 mg a day does. What the trials found, in the people and at the doses they studied, is on the research page: resveratrol benefits: what the research does and doesn't show.
How much resveratrol is in food?
A survey of about 135 red wines from one Spanish grape variety measured total resveratrol at 18.8 mg per litre on average and about 30 mg per litre at the top. A 150 mL glass at 30 mg/L is about 4.5 mg (our arithmetic), far below a capsule. We have not verified per-serving figures for grapes, blueberries, grape juice or red wine vinegar, so we do not quote any.
Questions people ask
How much resveratrol per day?
No official figure exists. Trials have used 75 mg to 5 g. Follow the directions on the label you have, or your healthcare professional's.
How much resveratrol should I take daily, and how often?
Ours is directed as one capsule twice a day, before meals. Do not exceed the recommended dose. If you take prescription medication or have a health condition, ask your doctor first (see resveratrol and medications).
Is 1,000 mg, 1,500 mg or 1,800 mg better than 500 mg?
We found no trial showing that more is better. In the 29-day study, GI symptoms appeared at 2.5 g and 5 g, and the 1 g enzyme study found changes in medicine-processing enzymes. Bigger numbers on a label can also be extract weight, so check what percentage is resveratrol.
How much resveratrol to be effective?
We cannot give an effective dose, because no trial we could verify used our dose and form and the results across trials are mixed.
How much resveratrol is in red wine or a glass of wine?
In the one survey above, up to about 4.5 mg in a 150 mL glass at the highest content, and less on average.
Can you take resveratrol every day?
The 29-day study ran daily at 0.5 to 5 g. We found no longer verified safety data, so we do not state a long-term answer. Talk to your doctor if you plan long-term use.
Sources
- Repeat dose study of the cancer chemopreventive agent resveratrol in healthy volunteers: safety, pharmacokinetics, and effect on the insulin-like growth factor axis In 40 healthy adults, 0.5 to 5 g a day for 29 days was called safe, but the two highest doses caused mild to moderate stomach and gut symptoms.
- Resveratrol modulates drug- and carcinogen-metabolizing enzymes in a healthy volunteer study In 42 healthy adults, 1,000 mg a day for 4 weeks changed how several liver enzymes that process medicines were working.
- High absorption but very low bioavailability of oral resveratrol in humans Most of a 25 mg dose was absorbed, but almost none stayed in the blood as plain resveratrol; it was converted to other compounds.
- Resveratrol supplementation does not improve metabolic function in nonobese women with normal glucose tolerance In nonobese postmenopausal women, 75 mg a day for 12 weeks changed none of the measured outcomes versus placebo.
- Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans In 11 obese men, 150 mg a day for 30 days was followed by changes in several metabolic markers; it was a small crossover study.
- Effects of resveratrol on memory performance, hippocampal functional connectivity, and glucose metabolism in healthy older adults In 46 overweight adults aged 50 to 75, 200 mg a day for 26 weeks was followed by a modest gain on one word-memory score versus placebo.
- Determination of piceid and resveratrol in Spanish wines deriving from Monastrell (Vitis vinifera L.) grape variety In one Spanish red-wine variety, total resveratrol ran from about 19 mg a litre on average to about 30 mg a litre at the high end.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
