If you're looking to give yourself a cognitive edge, Natrol® Cognium® Memory Extra Strength is a highly effective, clinically proven way to do it. Featuring Silk Protein Hydrolysate, a natural protein found in silkworm cocoons that has been proven in several clinical trials, this formula helps promote concentration, memory, mental focus, learning and more and is 100% stimulant free. Extra Strength Cognium begins to show results in only about four weeks.