Cypionax is a single-ester, long-acting form of testosterone. Due to the length of Cypionax ester (8 carbons) it is stored mostly in the adipose tissue upon intra-muscular injection, and then slowly but very steadily released over a certain period of time. Cypionax is one of the most popular form of testosterone used in the USA due to the fact that it is quite easy to obtain in the black market and at more and more competitive price.