Anabolic steroids can cause many adverse effects . Most of these side effects are dose dependent, the most common being elevated blood pressure , especially in those with hypertension ,  and harmful cholesterol levels: some steroids cause an increase in bad cholesterol and a decrease in good cholesterol .  Anabolic steroids such as testosterone also increase the risk of cardiovascular disease ,  or coronary artery disease   in men with high risk of bad cholesterol . Acne is fairly common among anabolic steroid users, mostly due to increases in testosterone stimulating the sebaceous glands .   Conversion of testosterone to dihydrotestosterone (DHT) can accelerate the rate of premature baldness for those who are genetically predisposed.
The pharmacodynamics of anabolic steroids are unlike peptide hormones. Water-soluble peptide hormones cannot penetrate the fatty cell membrane and only indirectly affect the nucleus of target cells through their interaction with the cell’s surface receptors . Conversely, as fat-soluble hormones, anabolic steroids are membrane permeable and influence the nucleus of cells by direct action. The pharmacodynamic action of anabolic steroids begin when the exogenous hormone penetrates the membrane of the target cell and binds to an androgen receptor located in the cytoplasm of that cell. From there, the compound hormone-receptor diffuses into the nucleus, where it either alters the expression of genes [ 20 ] or activates processes that send signals to other parts of the cell. [ 21 ] Different types of anabolic steroids bind to the androgen receptor with different affinities , depending on their chemical structure. [ 3 ] Some anabolic steroids such as methandrostenolone bind weakly to this receptor in vitro, but still exhibit androgenic effects in vivo. The reason for this discrepancy is not known. [ 22 ] On the other hand, steroids such as oxandrolone bind tightly to the receptor and act mostly on gene expression . [ citation needed ]
Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes.