Researchers have suggested that consumption of resveratrol may potentially benefit numerous clinical conditions, including cancer, cardiovascular disease, obesity and related conditions including diabetes and non-alcoholic fatty liver disease, and neurological diseases.  However, current evidence is insufficient to support a definitive place in therapy for resveratrol.

• Resveratrol Supplements May Help Lower Blood Pressure.
  A 2015 review concluded that high doses may help reduce the pressure exerted on artery walls when the heart beats (Source).
• It Has a Positive Effect on Blood Fats
  A 2016 study fed mice a high-protein, high-polyunsaturated fat diet and also gave them resveratrol supplements.  Researchers found the average total cholesterol levels and body weight of the mice decreased, and their levels of "good" HDL cholesterol increased (Source).
  In another study, participants were given grape extract that had been boosted with extra resveratrol.  After six months of treatment, their LDL had gone down by 4.5% and their oxidized LDL had gone down by 20% compared to participants who took an unenriched grape extract or a placebo (Source).
• It Lengthens Lifespan in Certain Animals
  Resveratrol’s ability to extend lifespan in different organisms has become a major area of research (Source).
  There's evidence that resveratrol activates certain genes that ward off the diseases of aging (Source).
  It works to achieve this in the same way as calorie restriction, which has shown promise in lengthening lifespans by changing how genes express themselves (Source, Source).
• It Protects the Brain
  Several studies have suggested that drinking red wine can help slow down age-related cognitive decline (Source, Source, Source, Source).   This may partly be due to the antioxidant and anti-inflammatory activity of resveratrol.
  It seems to interfere with protein fragments called beta-amyloids, which are crucial to forming the plaques that are a hallmark of Alzheimer's disease (Source, Source).
• It May Increase Insulin Sensitivity
  Resveratrol has been shown to have several benefits for diabetes, at least in animal studies.
  These benefits include increasing insulin sensitivity and preventing complications from diabetes (Source, Source, Source, Source).
  An explanation for how resveratrol works is that it may stop a certain enzyme from turning glucose into sorbitol, a sugar alcohol.   When too much sorbitol builds up in people with diabetes, it can create cell-damaging oxidative stress (Source, Source).
  Here are a few more benefits resveratrol may have for people with diabetes (Source):
  • May protect against oxidative stress: Its antioxidant action may help protect against oxidative stress, which causes some of the complications of diabetes.
  • Helps decrease inflammation: Resveratrol is thought to lessen inflammation, a key contributor to chronic diseases, including diabetes.
  • Activates AMPK: This is a protein that helps the body metabolize glucose.  Activated AMPK helps keep blood sugar levels low.

  Resveratrol may even provide more benefits for people with diabetes than those who don't have it. In one animal study, red wine and resveratrol were actually more effective antioxidants in rats with diabetes than in rats who didn't have it (Source).

• It May Ease Joint Pain
  Arthritis is a common affliction that leads to joint pain and loss of mobility (Source).
  Plant-based supplements are being studied as a way to treat and prevent joint pain.  When taken as a supplement, resveratrol may help protect cartilage from deteriorating (Source, Source).
  Cartilage breakdown can cause joint pain and is one of the main symptoms of arthritis (Source).
  One study injected resveratrol into the knee joints of rabbits with arthritis and found that these rabbits suffered less damage to their cartilage (Source).
  Other research in test tubes and animals has suggested that the compound has potential to reduce inflammation and prevent damage to joints (Source, Source, Source, Source).
• Resveratrol May Suppress Cancer Cells
  Resveratrol has been studied, especially in test tubes, for its ability to prevent and treat cancer. However, results have been mixed (Source, Source, Source).
  In animal and test-tube studies, it has been shown to fight several kinds of cancer cells, including gastric, colon, skin, breast and prostate (Source, Source, Source, Source, Source).
  Here's how resveratrol may combat cancer cells:
  • It may inhibit cancer cell growth:  It may prevent cancer cells from replicating and spreading (Source).
  • Resveratrol may change gene expression:  It can change the gene expression in cancer cells to inhibit their growth (Source).
  • It can have hormonal effects:  Resveratrol may interfere with the way certain hormones are expressed, which may keep hormone-dependent cancers from spreading (Source).

• However, since the studies so far have been carried out in test tubes and animals, much more research is needed to see if and how this compound might be used for human cancer therapy.

No major risks have been revealed in studies that have used resveratrol supplements.  Healthy people seem to tolerate Resveratrol well (Source).  There are some cautions.  

High doses have been shown to stop blood from clotting in test tubes, it is possible it could increase bleeding or bruising when taken with anti-clotting drugs, such as heparin or warfarin, or some pain relievers (Source, Source).

Resveratrol also blocks some enzymes that help clear certain compounds from the body.  That means some medications could build up to unsafe levels.  These include certain blood pressure medications, anxiety meds and immunosuppressants (Source).

Adverse events for lower doses and shorter courses of treatment have been rare.  

Pregnancy and breast-feeding:  Resveratrol is LIKELY SAFE when used in amounts found in some foods. However, during pregnancy and breast-feeding, the source of resveratrol is important.  Resveratrol is found in grape skins, grape juice, wine, and other food sources.  Wine should not be used as a source of resveratrol during pregnancy and breast-feeding.  

Children:  Resveratrol is POSSIBLY SAFE in children when sprayed in the nostrils for up to 2 months. 

Bleeding disorders:  Resveratrol might slow blood clotting and increase the risk of bleeding in people with bleeding disorders.  

Hormone-sensitive condition such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids:  Resveratrol might act like estrogen.  If you have any condition that might be made worse by exposure to estrogen, don't use resveratrol.   

Surgery:  Resveratrol might increase the risk of bleeding during and after surgery.  Stop using resveratrol at least 2 weeks before a scheduled surgery. 

If you currently use medications, then you may want to check with a doctor before trying resveratrol.

Evidence from clinical studies is insufficient to provide comprehensive dosing guidelines. Single-dose studies suggest that a safe daily dosage for a person weighing 70 kg maybe 450 mg/day.

Dosages above 1 g/day appear to have been well tolerated in a short-term (2-week) trial but have been reported to cause adverse effects in another study.

The lower end of supplementation tends to be for cardiovascular health, insulin sensitivity, and longevity for somebody who is otherwise unhealthy is 5-10mg daily.

For persons who are otherwise healthy, dosages between the range of 150-445mg have been used (with no clear indication for what is the optimal dose).

Supplementing for cerebral blood flow requires a dose in the 250-500mg range whereas supplementation for aromatase inhibition requires 500mg.

When taken by mouth, Resveratrol is LIKELY SAFE when used in the amounts found in foods. When taken in doses up to 1500 mg daily for up to 3 months, resveratrol is POSSIBLY SAFE. Higher doses of up to 2000-3000 mg daily have been used safely for 2-6 months. However, these higher doses of resveratrol are more likely to cause stomach problems.