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 have a long history of culinary and medicinal use.

What Is Grape Seed Extract Used For?

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

Today, we know that grape seed extract contains oligomeric proanthocyanidin (OPC), an antioxidant that is believed to improve certain health conditions. Some scientific evidence supports the use of of grape seed or grape seed extract to reduce poor blood flow in the legs and to reduce eye stress due to glare.

In alternative medicine, grape seed extract is purported to help with these additional conditions:

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

Additional research has investigated the following purported benefits of grape seed extract.


Proponents claim that grape seed extract can help protect against cancer. In laboratory studies, scientists have demonstrated that grape seed can help fight free radicals (chemical byproducts known to cause DNA damage associated with cancer). However, it is still unclear whether grape seed also lowers cancer risk in humans.

Diabetes-Related Complications

In a 2009 study of 32 type 2 diabetes patients at high cardiovascular risk, participants took 600 mg of grape seed extract or a placebo every day for four weeks. Study results showed that grape seed extract significantly improved markers of inflammation and glycemia. The study's authors suggest that grape seed extract may have a therapeutic role in decreasing cardiovascular risk.

High Blood Pressure

In a 2009 study of subjects with metabolic syndrome, researchers found that four weeks of treatment with grape seed extract lowered both systolic and diastolic blood pressure.

Metabolic syndrome is marked by a cluster of health problems (including excess belly fat, high blood pressure, high cholesterol, insulin resistance, and inflammation) known to raise your risk of heart disease and type 2 diabetes.

Alzheimer's Disease

Grape seed extract may help delay the development of Alzheimer's disease, according to an animal study published in 2009. In tests on mice, 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.

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.

Grape seed extract capsules
Verywell / Anastasia Tretiak

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 150 mg to 750 mg daily for six to 12 weeks have been used in studies in which scientists were learning about eye stress and poor blood flow. However, your recommended dose may vary based on gender, age, weight, and medical history.

If you considering using grape seed extract, talk with your 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), a byproduct of the wine industry, is found in extracts of grape skin and grape seeds.

Some medical sources say you should look for products that are standardized to 40 to 80 percent proanthocyanidins or an OPC content of not less than 95 percent.

Before buying this or any supplement, the National Institutes of Health (NIH) recommends that you look for a Supplement Facts label on the product. This label will give you information about 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 pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has often not been established. 

Common Questions

Will eating grapes give me the same benefits of 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 certain nutritional benefits. The grapes that are most often studied regarding the health benefits mentioned above 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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  • Kar P, Laight D, Rooprai HK, Shaw KM, Cummings M. "Effects of Grape Seed Extract in Type 2 Diabetic Subjects at High Cardiovascular Risk: a Double Blind Randomized Placebo Controlled Trial Examining Metabolic Markers, Vascular Tone, Inflammation, Oxidative Stress and Insulin Sensitivity." Diabet Med. 2009 26(5):526-31.
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