Virtually all banned substances occur naturally in the body. Once steroids were one of the most commonly used of all banned substances. They increase muscle growth but their effect on performance is controversial. The greatest effect occurs in women. If they take male steroid hormones like testosterone, they get definite advantages, but at great cost.
Women athletes on steroids can find their voices deepening and grow facial hair.
A naturally occurring chemical in the body, it is secreted by the pituitary gland. It appears to trim fat, build muscle and possibly slow down the ageing process. Unfortunately there is no reliable test. Australian customs officials discovered 13 vials of growth hormone hidden in the luggage of Chinese swimmer Yuan Yuan before the world championships in 1998. Another controversial and naturally occurring hormone, its use increases the number of red cells in the blood.