Grape seed extract (GSE) is packed with polyphenols and other antioxidants. Many GSE products are available, but their quality and safety can greatly vary. Learn about the dosage range used in clinical trials, reported side effects, and what users say about different GSE supplements. <\/p>\n\n\n\n\n\n\n\n
Grape seed extract is a concentrated source of antioxidant polyphenols from grape seeds [R<\/a>, R<\/a>, R<\/a>]. <\/p>\n\n\n\n Supplement manufacturers usually source grape seeds from winemakers, and they extract proanthocyanidins and other healthy components.<\/p>\n\n\n\n For other grape seed products and their uses, check out the FAQ section below.<\/p>\n\n\n\n Grape seed extract was safe in clinical trials, mostly causing side effects at rates similar to placebo. The following side effects have been reported [R<\/a>, R<\/a>, R<\/a>]:<\/p>\n\n\n\n People who are allergic to grapes shouldn’t use grape seed extract. <\/p>\n\n\n\n Animal safety studies suggested that grape seed extract was safe in long-term lab settings, but proper human safety data are lacking [R<\/a>, R<\/a>, R<\/a>].<\/p>\n\n\n\n Grape seeds and other foods rich in polyphenols may hinder iron absorption. To avoid iron deficiency, don\u2019t take grape seed extract supplements with iron-rich foods (meat, legumes, greens). If you do, you can combine it with vitamin C<\/a> to improve iron absorption [R<\/a>, R<\/a>].<\/p>\n\n\n\n Pesticides and yeast toxins have been identified in grape skin, juice, and wine made from grapes in some regions of the world. For example, pesticides were found in most grape juice products produced and sold in Canada. On the other hand, juice and red wine from sold in Brazil contained the yeast toxin called Ochratoxin A [R<\/a>, R<\/a>]. <\/p>\n\n\n\n These toxins have not been reported to occur in grape seed extract. <\/strong><\/p>\n\n\n\n Children and pregnant and breastfeeding women should avoid grape seed extract<\/strong> because we still lack evidence of its safety in these sensitive groups.<\/p>\n\n\n Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let him know about all drugs and supplements you are using or considering.<\/em><\/p>\n\n\n\n Although quite safe on its own, grape seed extract may inhibit some liver enzymes (CYP3A4<\/a> and CYP1A2) and thus impact the metabolism of certain drugs, such as [R<\/a>, R<\/a>]:<\/p>\n\n\n\n Grape seed extract prevents blood clotting and may thus interfere with blood thinners<\/strong> such as warfarin (Coumadin) [R<\/a>].<\/p>\n\n\nReported Side Effects<\/span><\/h3>\n\n\n\n
Effects on the Absorption of Nutrients<\/span><\/h3>\n\n\n\n
Safety Concerns<\/span><\/h3>\n\n\n\n
Children and Pregnant Women<\/span><\/h3>\n\n\n\n
Drug Interactions<\/span><\/h3>\n\n\n\n