Norbolethone

Norbolethone (Genabol) is an anabolic steroid. It was first developed in 1966, and tested for use as an agent to encourage weight gain and for the treatment of short stature, but was never marketed commercially. It subsequently showed up in urine tests on athletes in competition in the early 2000s.

Norbolethone was found to have been brought to the market by the chemist Patrick Arnold, of the Bay Area Laboratory Co-operative (BALCO), an American nutritional supplement company. It is reputed to have been the active ingredient in the original formulation of the "undetectable" steroid formulation known as "The Clear" before being replaced by the more potent drug tetrahydrogestrinone.