
Common Names
- Grape Seed Oil
- Grape Seed Extract
- Muskat
For Patients & Caregivers
Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.
How It Works
Although it has antioxidant properties, grape seed has not been shown to treat or prevent cancer.
Grape Seed Extract is derived from the oil that comes from ground red wine grapes. The extract contains a substance called proanthocyanidin which has antioxidant activities. Proanthocyanidins may help improve cholesterol levels, but studies are limited. There are also very few studies that have been conducted in cancer patients. One such study did not find any improvements in radiotherapy side effects among breast cancer patients.
Grape seed extract should not be confused with Grapefruit seed extract (also known by the acronym GSE), which has different biological effects.
Purported Uses
-
To lower high cholesterol
Grape seed may improve lipid profiles, but studies are limited and larger trials are needed. -
To treat atherosclerosis
Although lab studies suggest antioxidant and cardioprotective effects, studies in humans are lacking. -
To address cancer side effects
Studies in cancer patients are limited and have yet to show benefit.
Do Not Take If
- You are taking warfarin or other blood thinners: Lab studies suggest grape seed may increase bleeding risk. Clinical relevance has yet to be determined.
- You are taking cytochrome P450 3A4 substrate drugs: Lab studies suggest grape seed may increase their side effect risks. Clinical relevance has yet to be determined.
- You are taking UGT substrate drugs: Lab studies suggest grape seed may increase their side effect risks. Clinical relevance has yet to be determined.
For Healthcare Professionals
Clinical Summary
Grape seeds are obtained as a by-product of wine production and ground to produce grape seed oil. Grape seed extract is marketed as a supplement for its antioxidant properties.
Preclinical studies of grape seed proanthocyanidin extract (GSPE) suggest cardioprotective (4) (5) and anticancer effects (16) (17). Other studies suggest synergistic effects with doxorubicin (13) or that it can help minimize various drug-induced toxicities (3) (15) (22) (23). Topical application accelerated wound contraction and closure (8).
Preliminary studies in humans suggest grape seed extract can reduce LDL (6), increase total serum antioxidant activity (7), and benefit patients undergoing coronary artery bypass surgery (11). Meta-analyses suggest GSE may lower systolic blood pressure and heart rate, but are mixed on whether it improves lipid, glucose, and inflammatory markers (24) (25). Other data suggest it may provide adjunctive benefit in patients with diabetic retinopathy (26).
Supplementation with grape seed may be associated with decreased risk of hematologic malignancies (21). In prostate cancer patients, a pulverized muscadine grape skin from Vitis rotundifolia was safe and tolerable (12), but clinical benefit needs to be assessed. Oral GSPE did not improve radiotherapy adverse effects of tissue hardness, pain, or tenderness in breast cancer patients (14).
Grape seed extract should not be confused with Grapefruit seed extract (also known by the acronym GSE), which has different biological effects.
Food Sources
Mechanism of Action
Proanthocyanidins and minor phenolic compounds found in GSPE are also found naturally in many foods including fruits, vegetables, chocolate, and tea. People generally consume 460-1000 mg/day of these combined substances (9). GPSE has protective effects on doxorubin-induced cardiotoxicity (3). Cardioprotective effects may be due to its ability to modulate anti-apoptotic genes and modify molecular targets such as DNA damage and repair, lipid peroxidation, and intracellular calcium homeostasis (5).
Adverse Reactions
Gastrointestinal upset (26)
Herb-Drug Interactions
- Anticoagulant/antiplatelet drugs: In vitro, grape seed has antiplatelet activity, and may increase the risk of adverse effects of these drugs (1) (19). Clinical relevance has yet to be determined.
- Cytochrome P450 3A4 substrates: In vitro, GSE inhibits CYP3A4 and may affect the intracellular concentration of drugs metabolized by this enzyme (18). Clinical relevance has yet to be determined.
- UGT (Uridine 5’-diphospho-glucuronosyltransferase) substrates: Grape seed modulates UGT enzymes in vitro and may increase the side effects of drugs metabolized by them (20). Clinical relevance has yet to be determined.