Testosterone Propionate is an esterified form of the base steroid testosterone, similar to cypionate and enanthate. The main difference with Testosterone Propionate and Cypionate and Enanthate is that Propionate is a very short ester and is still released quite fast. As such more frequent injections are needed. Levels will peak after 24-36 hours. Testosterone Propionate also stacks well with some other steroids, for bulking is the best stact to use Nandrolone Decanoate or Boldenone Undeclynate, and can addition Methandrostenlone or Oxymetholone for 5-6 weeks, at the beginning to fasten things. With testosterone, almost any combination is possible. Because testosterone is always the stronger compound in a stack.