4-Chlorodehydromethyltestosterone, sold under the brand name Oral Turinabol, is an anabolic steroid. It is a chlor-substituted version of methandrostenolone (Dianabol). Turinabol was the first original product of Jenapharm, an East German pharmaceutical company. The patent registration took place in 1961. The idea of combining the structures of 4-chlorotestosterone and methandrostenolone originated from the chemist Albert Stachowiak. At the time this represented a unique dissociation of anabolic and androgenic effects after oral administration. The product had been introduced for clinical use in 1965. Turinabol was the key steroid administered to approximately 10,000 athletes from East Germany (GDR). The doping program was run by the East German Government from about 1968 thru until 1989 when the Berlin wall was destroyed. The doping program was known as STASI 14.25. The doping was done in secret and it was only in the 1990s when Franke and Berendonk looked closely at the original archived information was the true scope of just how well-planned and successful the doping regime had been (in terms of medal success and world record performances).