Nutricost D-Aspartic Acid Powder in Blue Raspberry flavor (10.7 oz / 300 g) is a dietary supplement designed to support male vitality and testosterone levels.For men who want to restore their vigor and vitality, D-aspartic acid is a natural supplement commonly used to boost male testosterone levels. Low testosterone can mean low energy, libido, and fertility. D-aspartic acid is active in the nervous and endocrine systems, and research suggests that it may have the ability to increase testosterone in men who are generally healthy.