The classic method incorporates extraction with organic solvents such as acetone, acetonitrile, ethyl acetate, and methanol.
[6] The US National Center for Complementary and Integrative Health reported that oral administration of grape seed extract (dose and frequency unreported) was well tolerated in people over 14 weeks.
[1] A 2016 meta-analysis concluded that grape seed extract, in a dose of under 800 milligrams per day over at least 8 weeks, might help to reduce systolic and diastolic blood pressure.
[7] People with metabolic syndrome had a more significant outcome (average of a 8½ mmHg decrease in systolic blood pressure) than in healthy subjects.
[10] In 2017, the Food and Drug Administration listed grape seed extract as a fake cancer cure that consumers should avoid.