A steroid cycle is a term commonly used to describe a period in time where an individual intakes anabolic steroids.

A "cycle" can last from two weeks to more commonly 6-12 weeks, or even longer. Supplying the body with exogenous hormones will suppress its own testosterone production.

The longer the body's endogenous supply of testosterone is suppressed, the harder it will be for their hypothalamus/pituitary/testicular axis (HPTA) to recover. More serious health risks are associated with longer cycles, such as testicular atrophy, gynecomastia, heart problems, liver diseases, and in extreme cases, permanent suppression of the HPTA, necessitating permanent testosterone therapy.

Many steroid cycles involve combining two or more drugs together, usually one being a potent androgen. Other drugs which act through more anabolic pathways can then be added as well. Professional and novice bodybuilders all over the world combine many drugs together in what is commonly referred to as a steroid stack.