Grape seed extract
Grape seed extract is made from the ground seeds of red wine grapes. For thousands of years, grapes - along with their leaves and sap - have been cultivated as both a food and a traditional remedy for conditions such as PMT and heart problems. However, there is no good evidence grape seed extract is effective at treating any medical condition.
Herbal remedies in the UK are regulated by the medicines body MHRA. It runs a traditional herbal registration scheme called THR. It has not yet issued a registration for grape seed extract.
Unlike licensing for mainstream medicines, registration doesn't mean a herbal remedy has been tested and proven to actually work.
It does mean the MHRA is satisfied the product is made to good quality standards with appropriate labelling and a product information leaflet. It also means the herb has been used in traditional remedies for more than 30 years.
Grape seed extract uses
There’s some evidence that grape seed extract is beneficial for a number of cardiovascular conditions. One 2003 study found grape seed extract "provides superior antioxidant efficacy as compared to Vitamins C, E and β-carotene." Other studies suggest grape seed extract might also help with a type of poor circulation (chronic venous insufficiency). However, a 2005 review of clinical trials involving over 4,000 participants tested the efficacy of grape seed extract along with other phlebotonics. It concluded: "There is not enough evidence to globally support the efficacy of phlebotonics for chronic venous insufficiency." More research is needed. Some studies suggest grape seed extract also reduces swelling and helps with eye diseases related to diabetes, but again, more research is needed.
Many people are interested in grape seed extract because it contains antioxidants. These are substances that studies suggest protect cells from damage and may help prevent many diseases. However, researchers still don’t know the full risks and benefits of using antioxidant supplements.
Researchers are studying grape seed extract to see if it might reduce the risks of some cancers. For now, the evidence is not clear.
Grape seed extract has been studied for use in many other conditions - ranging from PMT to skin damage to wound healing - but the results have been inconclusive.
Grape seed extract dose and instructions for use
There is no firmly established dose of grape seed extract. Doses of between 100-300mg/day have been used in studies and are prescribed in some European countries. No one knows what the highest safe dose is.
Grape seed extract food sources
Grape seed extract comes from grapes. There are no other food sources.
Grape seed extract supplement information
Grape seed extract is often sold in tablets, capsules and liquids. Some experts suggest it’s most effective when taken with vitamins C and E. Like any supplement, keep grape seed extract supplements in a cool, dry place, away from humidity and direct sunlight.
Grape seed extract warnings
- Side effects. Grape seed extract is generally considered safe. Side effects may include headache, itchy scalp, dizziness and nausea.
- Risks. People allergic to grapes should not use grape seed extract. If you have a bleeding disorder or high blood pressure, talk to your GP before you start using grape seed extract.
- Interactions. If you take any medicines regularly, talk to your GP before you start using grape seed extract. It could interact with drugs like blood thinners, NSAID painkillers (like aspirin, ibuprofen and naproxen), certain heart medicines, cancer treatments and others.
Given the lack of evidence about its safety, grape seed extract is not recommended for children or for women who are pregnant or breastfeeding.