D- Aspartic Acid
D-Aspartic Acid (DAA) is an amino acid that plays a role in creating and releasing hormones within the body. DAA is especially popular for its testosterone building capabilities. Studies show that individuals taking DAA had higher circulating luteinizing hormone levels and higher levels of free testosterone after 12 days of use.
B vitamins work great in conjunction with DAA to help to elevate circulating free testosterone.
...Specifically our NO3-T. Studies show that nitrate supplementation allows exercise to be tolerated for a greater period of time - which may translate into more repetitions being performed during a given set of exercise and/or a greater load to be used during each set of exercise.
As a hormone regulating more than 1000 vitamin D-responsive human genes, vitamin D may influence athletic performance. Studies show that healthy men who supplemented with 3332 IU of vitamin D daily for one year, noted a significant increase in total, bioactive, and free testosterone levels. For optimal vitamin D absorption, taking vitamin D with the largest meal of the day seems most appropriate.