Boldenone (1,4-androstadiene-3-one-17ß-ol, available as the undecylenate ester) is a synthetic anabolic steroid with a similar structure to testosterone. Boldenone is like many other synthetic steroids. It is a potent anabolic agent at low doses and at high doses possesses both anabolic and androgenic properties. Because it acts like an anabolic steroid, it can suppress the normal synthesis of testosterone in the testes. When the drug is taken in high doses, it can also be converted into estrogen, which can result in gynecomastia and also leads to water retention.