6 Serious Side Effects Of Grape Seed Extract

Take a deep dive into the perks and risks of this fruity extract before consuming it.

Medically reviewed by Mary-Walker HallMary-Walker Hall, RDN
By Tanya ChoudharyTanya Choudhary, ISSA Certified Specialist In Fitness & Nutrition  • 

Made from the seeds of grapes, grape seed extract is rich in antioxidants and several other nutrients. Commonly used as a dietary supplement, grape seed extract may benefit your health in the long term and reduce the risk of developing medical conditions. What you are probably not aware of are the many side effects of grape seed extract. In this article, we take a deeper look at the reported side effects and how they may impact your health.

Grape Seed Extract – A Brief

Well, as evident from its name, grape seed extract comes from grapes and has a high concentration of Vitamin E, linoleic acid, flavonoids and phenolic procyanidins. Grape seed extract is derived from grape seeds that are extracted, dried and purified to produce polyphenolic compounds-rich extract that also has well documented antioxidant, antimicrobial and anti-inflammatory properties (1).

It is mostly used for industrial purposes while oral grape seed extract is used in capsules or tablets. Grape seed extract is believed to have potential health benefits. It is a rich source of antioxidants and oligomeric proanthocyanidins which possess several health benefits.

protip_icon Did You Know?
A team of geneticists extracted DNA from an ancient grape seed, compared it with recently grown grapes, and matched it to Savagnin blanc grapes. This means that this grape type has grown unchanged for close to a millennium, surviving the Hundred Year’s war, the French Revolution, and both the World Wars.

Though there is a lack of scientific evidence about the potential health benefits of grape seed extract, it does have some adverse effects associated with it. Besides, there is dearth of information regarding the recommended dose of grape seed extract which further increases the risk. Doses of between 100-300 milligrams/day have been used in studies and are prescribed in some European countries (2).

Grape Seed Extract Side Effects

Given below are some of the grape seed extract side effects which can turn out be serious:

1. Bleeding

Prolonged bleeding as a side effect of grape seed extract

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One of the most prominent side effects of grape seed extract is bleeding, both internal and external. It can slow down blood clotting, thus leading to prolonged bleeding in cuts and bruises. Grape seed extract can also cause internal bleeding that includes symptoms of gastrointestinal bleeding like blood in vomit, bright red blood in stools, and tarry stools.

Since grape seed extract slows down blood clotting, it is not suitable for those having to undergo surgery as it might cause extra bleeding. Hence, the use of grape seed extract should be stopped at least two weeks before a scheduled surgery.

2. Hemorrhagic Stroke

Doctor explaining patient's hemorrhagic stroke as a side effect of grape seed extract

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One of the most serious side effects of grape seed extract is hemorrhagic stroke, which is also a form of internal bleeding. It is characterized by the bursting of blood vessels inside the brain. The blood clot inside the brain irritates the brain tissues and causes swelling.

Symptoms of hemorrhagic stroke include coma, unconsciousness, headache, nausea, difficulty in swallowing, vision or speech impairment, weakness or numbness in arms or legs, loss of coordination, etc.

3. Allergic Reactions

Woman experiencing allergic reaction as a side effect of grape seed extract

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Grape seed extract can also cause allergic side effects like rashes, itching, swelling of lips, mouth, tongue or throat, hives, difficulty in breathing or wheezing, etc. It is advisable to seek immediate medical attention if any of these allergic reactions is observed.

protip_icon Fun Fact
Grape seed extract has been used in West Asia and parts of Europe for healthcare dating back 6000-8000 years ago. It was used to moisturize the skin and for its antioxidant property.

4. Unsuitable For Pregnant And Nursing Women

Pregnant woman thinking of consuming grape seed extract

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Pregnant women and those trying to conceive should avoid using supplements having grape seed extract as an ingredient, as these supplements have no medical recommendation. Besides, nursing women should consult their gynaecologist before using grape seed extract. This is because grape seed extract is considered a herbal medicine and herbal medicines are not standardized.

5. Drug Interactions

Due to its potential blood thinning effects, grape seed extract can react with certain drugs, that include medicines for blood thinning. It also can react with anti-platelet drugs as well as pain relieving drugs like aspirin and ibuprofen. Cholesterol lowering drugs and prescription drugs like Methotrexate can also react with it. Hence, grape seed extract should not be used with any of these medications without medical advice.

6. Other Minor Side Effects

Woman experiencing dry and itchy scalp as a side effect of grape seed extract

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Grape seed extract may also cause adverse effects like dry or itchy scalp, dizziness, and nausea (3). Intake of grape seed extract may lead to other minor side effects like dry mouth, sore throat, cough, infections, abdominal pain, stomach upset, indigestion, and muscular problems.

Infographic: 4 Serious Side Effects Of Grape Seed Extract

Grape seed extract has lately become popular for its anti-inflammatory and antioxidant properties. It is a herbal medication, but consuming it excessively can lead to adverse effects on the body. Check out the infographics below to learn about the four major side effects of grape seed extract.

4 serious side effects of grape seed extract (infographic)

Illustration: StyleCraze Design Team

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Download Infographic in PDF version

Despite its common use in dietary supplements and capsules, grape seed extract may be harmful if consumed in excessive amounts. The side effects of grape seed extract range from increased risk of bleeding to hemorrhagic stroke. Furthermore, it may cause dry scalp, indigestion, sore throat, or dizziness. In some cases, grape seed extract may trigger allergic reactions or interfere with the functioning of certain medications, especially blood thinners. Avoid such complications by limiting your intake or abstaining from it altogether. Go for the supplement only after consulting your doctor.

Frequently Asked Questions

Can you take grape seed extract every day?

Yes. Moderate consumption of grape seed extract can benefit your health in many ways. However, excess intake may lead to a few adverse effects.

What time of day should you take grape seed extract?

You can take grape seed extract whenever you want to, at any time of the day.

Key Takeaways

  • Although grape seed extract has several health benefits, its high dosages may cause unwanted side effects such as nausea, wooziness, and headaches.
  • It might interact with drugs for blood thinning and make bleeding more likely.
  • Additionally, grape seed extract may interact with several cancer treatments and reduce their effectiveness.
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