Cingestol

Cingestol (INN, USAN) (former tentative brand name Lutisan), also known as 17α-ethynylestr-5-en-17β-ol, is a steroidal progestin of the 19-nortestosterone group that was never marketed. It was synthesized in 1969 and was developed in the 1970s by Organon as a low-dose, progestogen-only contraceptive,   but in 1984, was still described as "under investigation". The drug is an isomer of lynestrenol with the double bond between C5 and C6.