D-Aspartic Acid is molecules that have many functions in the human body. D-Aspartic Acid is commonly used to reduce feelings of tiredness, improve athletic performance, and increase the size and strength of your muscles. Aspartic acid D can increase the release of hormones in the brain that will ultimately lead to the production of testosterone! Aspartic Acid D is a very popular testosterone boosting supplement. Our product is 100% made in the USA. Non-GMO and Vegan.