What Is Grape Seed Extract?

The Natural Supplement May Boost Heart Health

Grape seed extract, capsules, and tablets

Verywell / Anastasia Tretiak

Grape seed extract (Vitis vinifera) is a natural substance available in capsule and tablet form. It is usually sourced from grape seeds provided by wine manufacturers. Grapes and grape seed extract (GSE) have a long history of culinary and medicinal use.

Since the time of ancient Greece, various parts of the grape have been used for medicinal purposes. There are reports that ancient Egyptians and Europeans used grapes and grape seeds as well.

Health Benefits

Today, we know that grape seed extract contains oligomeric proanthocyanidin (OPC), an antioxidant that is believed to improve certain health conditions. Limited—and sometimes conflicting—scientific evidence suggests grape seed extract may have benefits for the following conditions:

Alternative medicine practitioners use grape seed extract to help with other conditions and situations:

  • Menopause symptoms
  • Constipation
  • Gastrointestinal disorders
  • Athletic performance

Scientific support for these potential benefits of grape seed extract is limited. There is not yet enough evidence to know for certain if grape seed extract can improve any of these conditions.

Research has investigated the following additional purported benefits of grape seed extract.

Grape seed proanthocyanidin extracts are some of the most powerful known antioxidants—they have 50 times the antioxidant activity of vitamin E and 20 times the antioxidant activity of vitamin C.

Cancer

In animal and laboratory studies, scientists have demonstrated that grape seed can help fight free radicals (chemical byproducts known to cause inflammation and oxidative stress associated with cancer). However, it is still unclear whether grape seed extract also lowers cancer risk in humans.

Small studies have shown increased antioxidant levels in human participants who consumed GSE. A 2021 review of 19 human trials also found significant improvements in oxidative stress after people took grape seed extract supplements. But they only showed a mild improvement in signs of inflammation.

To date, however, few studies have been performed in people, and those that have been performed are often conflicting. As a result, insufficient evidence exists to evaluate these benefits for humans.

Cardiovascular Health

Grape seed extract may have heart-health benefits. Some studies have suggested it may modestly improve blood pressure, cholesterol, and C-reactive protein. However, evidence is conflicting—other studies have shown no effect on the same measures.

Grape seed extract may be more cardioprotective for those who are overweight or severely overweight. One small study of 40 people showed improvement in several heart disease risk factors—including cholesterol levels—when they took GSE supplements and followed a calorie-restricted diet for 12 weeks.

Another small trial by the same authors showed that taking 300mg a day of grape seed extract reduced waist circumference and several inflammatory markers in those who were overweight or severely overweight.

Diabetes

There is some evidence suggesting grape seed extract can be beneficial for people with diabetes. A 2020 review of 15 small studies found that grape seed extract lowered fasting blood sugar, but it did not affect HbA1c—a more accurate, longer-term measure of blood sugar levels. Another review found it may also improve LDL and total cholesterol and blood pressure.

Grape seed extract has blood-thinning effects, and it may affect how the liver functions and metabolizes medication. Be sure to talk with a healthcare provider before using it.

High Blood Pressure

As with other cardiovascular indicators, evidence regarding grape seed extract’s effects on blood pressure is conflicting. A 2016 meta-analysis of 16 small clinical trials found grape seed extract lowered blood pressure somewhat overall, but had more significant benefits for younger or overweight people, as well as for people who already had a metabolic condition, such as metabolic syndrome. The authors suggested a large-scale clinical trial is warranted.

If you have high blood pressure, do not combine high doses of grape seed extract with vitamin C. The combination might worsen blood pressure, says the National Institutes of Health.

Alzheimer's Disease

Grape seed extract shows some promise in helping to delay the development of Alzheimer's disease. In tests on mice, for example, scientists discovered that grape seed extract eased inflammation and prevented the accumulation of substances known to form the brain plaques associated with Alzheimer's disease. However, most of the evidence for this benefit comes from animal and lab trials. Further study in people is necessary.

Possible Side Effects

Grape seed extract is generally well tolerated when taken by mouth. However, it may occasionally cause adverse effects such as headache, dry or itchy scalp, dizziness, or nausea.

Dosage and Preparation

Due to the lack of supporting research, it's too soon to recommend a specific dose of grape seed extract for any health purpose. Different doses of the extract have been used in research.

For example, doses ranging from 100 mg to 400 mg daily for six to 12 weeks have been used in studies. However, your recommended dose may vary based on gender, age, weight, and medical history.

If you are considering using grape seed extract, talk with a primary care provider first. Self-treating a condition and avoiding or delaying standard care may have serious consequences.

What to Look For

Grape seed extract is available in capsules and tablets and as a liquid. The antioxidant compound oligomeric proanthocyanidin (OPC) is found in extracts of grape skin and grape seeds.

Before buying this or any supplement, the National Institutes of Health recommends that you look for a Supplement Facts label on the product. This label will tell you the amount of active ingredient contained in each serving as well as information about other added ingredients.

Note that in the United States and some other countries, dietary supplements are largely unregulated and supplements are not tested for safety. As a result, the content of some products may differ from what is specified on the product label. If you choose to use this supplement, look for a product with a seal of approval from a third-party organization that provides quality testing, such as U.S. Pharmacopeia, ConsumerLab.com, and NSF International.

Also keep in mind that the safety of supplements in children and people who are pregnant, nursing, who have medical conditions or who are taking medications has often not been established. 

Common Questions

Will eating grapes give me the same benefits as grape seed extract?

Grapes can be a very healthy snack, but the concentration of the antioxidant OPC will be much higher in the extract than it will be when you consume a single serving of grapes.

What kind of grapes are best for my health?

Any kind of grape—just like every whole fruit—provides nutritional benefits. The grapes that are most often studied for their health benefits are red wine grapes. These grapes are sometimes, but not always, available in grocery stores.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • Grape Seed. Penn State Hershey. Milton S. Hershey Medical Center. Health Information Library

  • Grape. Natural Medicines Database. Professional Monograph. 2/6/2019

  • Grape Seed. Memorial Sloan Kettering Cancer Center. About Herbs, Botanicals, and Other Products. March 30, 2018

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  • National Center for Complementary and Alternative Medicine. "Grape Seed Extract [NCCAM Herbs at a Glance]" NCCAM Publication No. D370. Created March 2007. Updated May 2008.
  • Sivaprakasapillai B, Edirisinghe I, Randolph J, Steinberg F, Kappagoda T. "Effect of Grape Seed Extract on Blood Pressure in Subjects With the Metabolic Syndrome." Metabolism. 2009 58(12):1743-6.
  • Wang YJ, Thomas P, Zhong JH, Bi FF, Kosaraju S, Pollard A, Fenech M, Zhou XF. "Consumption of Grape Seed Extract Prevents Amyloid-Beta Deposition and Attenuates Inflammation in Brain of an Alzheimer's Disease Mouse." Neurotox Res. 2009 15(1):3-14.