Designer Physique Testosterone Boost contains D-Aspartic Acid which is a non-essential amino acid that helps to increase testosterone levels in both male and female, muscle mass and athletic performance, coupled with decreases in body fat and levels of fatigue. After taking D-Aspartic Acid for 12 days, there is a 33 percent increase in luteinising hormone and a 42 percent increase in testosterone levels. Other benefits are better sleep quality, high libido, positive mood and more energy. No added sugar or sweeteners. Gluten free, dairy-free and lactose-free.