This fact sheet provides basic information about grape seed extract--uses, potential side effects, and resources for more information. The grape seeds used to produce this extract are generally obtained from wine manufacturers.

Common Name--grape seed extract

Latin Name--Vitis vinifera

What It Is Used For

• Grape seed extract is used for conditions related to the heart and blood vessels, such as atherosclerosis (hardening of the arteries), high blood pressure, high cholesterol, and poor circulation.
• Other reasons for the use of grape seed extract include complications related to diabetes, such as nerve and eye damage; vision problems, such as macular degeneration (which can cause blindness); and swelling after an injury or surgery.
• Grape seed extract is also used for cancer prevention and wound healing.

How It Is Used

Grape seed extract is prepared from the seed of grapes. It is available in capsule and tablet forms.

What the Science Says

• Laboratory studies have shown that grape seed contains antioxidants-substances that prevent cell damage caused by free radicals, which are highly reactive molecules that can damage cell function. However, it is still unclear how grape seed might affect human health.
• Grape seed extracts have shown some beneficial antioxidant effects in preliminary clinical trials. However, few trials have looked at specific diseases or conditions, and little scientific evidence is available.
• A study funded by the National Cancer Institute (NCI) found that grape seed extract did not reduce the hardening of breast tissue that can occur after radiation therapy for breast cancer.
• NCI is also funding studies evaluating whether grape seed extract is effective in preventing breast and prostate cancers.
• NCCAM is studying whether the action of grape seed extract and its components may benefit the heart or have protective effects in the brain.

Side Effects and Cautions

• Grape seed extract is generally well tolerated when taken by mouth. It has been used safely for up to 8 weeks in clinical trials.
• Side effects that have been reported most often include headache; a dry, itchy scalp; dizziness; and nausea.
• The interactions between grape seed extract and medicines or other supplements have not been carefully studied.
• Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Sources:

Brooker S, Martin S, Pearson A, et al. Double-blind, placebo-controlled, randomised phase II trial of IH636 grape seed proanthocyanidin extract (GSPE) in patients with radiation-induced breast induration. Radiotherapy and Oncology. 2006;79(1):45-51.

Clouatre DL, Kandaswami C. Grape seed extract. In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005:309-325.

Grape. Natural Medicines Comprehensive Database Web site. Accessed on March 13, 2007.

Grape seed (Vitis vinifera, Vitis coignetiae). Natural Standard Database Web site. Accessed on March 13, 2007.

NCCAM Publication No. D370
March 2007