A nutritional supplement composition is formulated for oral administration and enhances cognitive function. It includes huperzine A, Ginkgo biloba, and acetyl-L-carnitine. The huperzine A, acetyl-L-carnitine, and Ginkgo biloba together account for at least 80 wt % of a dosage unit of the composition. The Ginkgo biloba is about 5.0% to about 12.0%, by weight of the huperzine A, acetyl-L-carnitine and Ginkgo biloba. The Ginkgo biloba and acetyl-L-carnitine are in a ratio of y:z respectively, wherein y is between about 690 and 1,030 for Ginkgo biloba and z is between about 8,000 and 12,000 for acetyl-L-carnitine.