As a result, you cannot buy them over the counter (OTC) — they require a consultation with a doctor. *Source: National Institutes of Health: NIDDK (2017). If you’re comfortable talking about ...

One study looked at the effects of the grape-based supplement Conigrape on cognition: One group of 57 adults took 250 milligrams of the supplement daily for 12 weeks, while 52 were in a control group.