Steroids are derived from male hormones, primarily testosterone. As derivatives of testosterone, steroids work by mimicking the role of endogenous testosterone in the human body.
    
Steroids are commonly taken in oral or injectable versions. Steroids start to work once they enter the circulation; steroids are distributed in different organs in the body, including the muscle. Steroids work for improved muscle mass via two mechanisms – production of proteins and prevention of the effects of cortisol on muscle tissue. These two mechanisms of steroids work positively for the muscle mass and strength gains.

Proteins are the building blocks of muscles – they facilitate muscle growth as well as muscle repair. This means that if you have improved protein production with the help of steroids bodybuilding is maximized.

Steroids also work to achieve anti-catabolism. Steroids sort of deactivate cortisol, the hormone responsible for the breakdown of proteins and amino acids to be used for energy source by the body for its activities.
 
Steroids also work through other means in promoting ideal bodybuilding. Steroids induce cell differentiation. Cell differentiation is the mechanism by which less specialized cells become specialized to perform specific functions in different tissues in organs. In the case of steroids, cell differentiation works for bodybuilding by redirecting increase of the number of cells that develop into fat-storage cells to muscle cells.