41.   Sold legally over the counter in synthetic form as an amino acid powder, it helps build muscle and speeds recovery from training.

42.   Such levels can signal the use of a synthetic form of the hormone EPO, a banned substance, but also can occur naturally.

43.   Synthetic forms are used in preventing miscarriages and treating some kinds of infertility.

44.   Synthetic forms of vitamin A, such as the acne medicine Accutane, are known to cause human birth defects.

45.   The naturally occurring substance can be used in synthetic form to boost performance, and is believed especially popular among cross-country skiers and cyclists.

46.   The research involved ipriflavone, a synthetic form of an estrogen-like substance found in plants such as soybeans.

47.   The synthetic form of ephedra has long been outlawed, and the FDA for years has sought to stop such sales, which occur mostly via the Internet.

48.   These naturally occurring substances, which can be used in synthetic form to boost performance, are among the designer drugs of choice in sports today.

49.   In synthetic form it is often prescribed to cancer patients.