Origin: Leaf of the ginkgo biloba tree, native to East Asia.
Dosage: Liquid, tablet, softgel and capsule and extract; typically 120 mg to 240 mg extract daily. Choose supplements standardized to 5- to 7-percent terpene lactones and 24-percent flavonol glycosides, the active ingredients in ginkgo.
Claims: Increases blood flow and circulation in Raynaud’s phenomenon and claudication (pain in legs or arms caused by reduced circulation due to blocked arteries).
What we know: There is no strong evidence that ginkgo improves mood, menopause symptoms, memory or fatigue.
Studies: Results from a 2002 double-blind, placebo-controlled trial of ginkgo for the treatment of Raynaud’s phenomenon showed that the supplements could reduce the number of disease flares by 56 percent.
Ginkgo’s side effects include stomach upset, dizziness or headaches. Do not take ginkgo if you are taking blood-thinning medication like aspirin, have epilepsy or experience seizures, have diabetes or are scheduled for surgery.