Grape seed extract: Benefits and side effects

Grape seed extract is an industrial derivative of grape seeds. It is rich in antioxidants and oligomeric proanthocyanidin complexes and may provide cardiovascular benefits.

Grape seed extract is available as a dietary supplement in a liquid form, tablets, or capsules. Supplements commonly contain between 50 and 100 milligrams (mg) of the extract.

Some research suggests that grape seed extract may help with the treatment of conditions such as high cholesterol, atherosclerosis, macular degeneration, poor circulation, and nerve damage. However, many of these health claims are still not completely backed by high-quality studies, but some evidence supports its use.

This article provides details on the benefits of grape seed extract as well as side effects and precautions associated with its use.

Proponents of grape seed extract (GSE) suggest it may possess many health benefits, such as improving blood flow and promoting wound healing. This is likely due to it containing proanthocyanidins. This is a compound that may have many potential uses.

However, the National Center for Complementary and Integrative Health (NCCIH) state that although some well controlled studies exist, there is not currently enough high-quality evidence supporting the use of GSE.

Listed below are some of the possible health benefits.

A 2021 review suggests that GSE may have potential uses in wound care products. Notably, it indicates that compounds in GSE could possess anti-inflammatory, antimicrobial, and antioxidant properties that support wound healing.

Additionally, a 2019 study investigating GSE suggests it may have beneficial therapeutic effects in promoting cesarian section wound healing. However, the study notes that further research into different concentrations of GSE and wound types is still necessary.

Growing research suggests that GSE may help with maintaining bone health. For example, a 2024 review of animal studies indicates that supplementation of GSE promotes bone formation and inhibits bone resorption. This is likely due to suppressing inflammation and slowing the formation of cells which absorb or break down bony tissue. The review also adds that GSE can help to increase bone health by increasing the density and mineral deposition.

Similarly, studies in 2020 on animal and in vivo models suggest that GSE could help with bone loss. However, as most studies on the topic are animal models or in vivo, more studies in humans are still necessary.

Some evidence also suggests that GSE may possess some antimicrobial properties. For example, the results of a 2023 study suggest that GSE may be effective against certain bacteria, such as Listeria monocytogenes. This is the species of bacteria responsible for listeria infections. Similarly, another 2023 study also notes that GSE is effective against L. monocytogenes, which could be beneficial for the food industry.

Other research suggests that GSE may also be effective against other foodborne bacteria, such as Staphylococcus aureus, Bacillus cereus, and Escherichia coli.

Proponents of GSE also suggest it may possess some cardiovascular benefits. For example, some research indicates that GSE may have cardio protective benefits and could help to reduce the risk of cardiovascular diseases.

One way GSE may help to improve heart health is by reducing blood pressure. Having higher blood pressure forces the heart to work harder, which can increase the risk of heart attack and heart failure. The results of studies in 2021 and 2023 both suggest that GSE can significantly lower blood pressure.

Other research also suggests that GSE could help improve blood flow and may be beneficial for those experiencing chronic venous insufficiency. This refers to when the valves in a person’s veins do not work properly, meaning the veins are less able to transport blood back to the heart.

GSE may also help to improve blood lipid markers. This refers to lowering low-density lipoprotein (LDL) cholesterol, triglyceride, and total cholesterol levels. This may help to provide cardiovascular benefits. However, more research is still necessary to confirm these benefits.

Growing research indicates that certain compounds, such as proanthocyanidins, may support brain health and prevent cognitive decline.

For example, a 2020 rat study suggests that GSE could help to inhibit oxidative stress and help preserve cognitive function. Similarly, a 2021 review indicates that GSE could have a positive effect on cognitive health. In particular, it suggests that GSE could benefit memory, movement, and executive functions.

However, the results of a 2023 trial in older adults with mild cognitive impairments suggest that GSE did not significantly improve symptoms. As such, further research is still necessary.

Generally, people are able to tolerate GSE well. However, possible side effects of GSE may include:

It is important to consult a doctor before taking grape seed extract as it can affect the way that certain medications are broken down in the liver. Additionally, GSE may act as an anticoagulant, or blood-thinner. It could increase the risk of bleeding if taken with other blood-thinners such as warfarin, clopidogrel, or aspirin.