Any steroid hormone that increases male characteristics (eg. facial hair, penis size at puberty, muscle bulk) is an androgen. Testosterone is the main natural androgen of the body. Men lacking in natural androgens can be given supplements by tablet, patch, implant or injection.
Androgens are naturally produced in the body in both sexes by the adrenal glands, in men by the testes (large amount), and in women in the ovaries (very small amounts).
The abuse of androgens by body builders and sportsmen is becoming a significant problem not only for the sports administrators, but also for the men themselves, particularly when they want to father a child.
The doses used by athletes are usually far higher than used in replacement therapy of men who have genuine hormone deficiencies, and they may be sourced from unreliable suppliers and medications designed for veterinary use may be given to humans. As a result, there may be significant side effects from androgen abuse.
The natural production of follicle stimulating hormone (FSH) and luteinising hormone (LH) by the pituitary gland is suppressed by the androgen supplements. These pituitary hormones are needed to produce natural testosterone in the testes. FSH is also essential for the production of sperm, so if the production and release of FSH from the pituitary is suppressed by androgen supplements the production of sperm will also be stopped.
With the prolonged use of artificial androgens, the pituitary hormones may be suppressed for so long that their production does not restart after the supplements are ceased, and there is a sudden drop in testosterone levels leaving the man impotent and sterile – he may not even grow a beard.
Other side effects of androgen supplements include oily skin, fluid retention, shrinkage of the testes, acne and liver damage. On the other hand it does increase the amount and strength of muscle tissue in the body, and decreases body fat.