Algestone acetonide (developmental code name W-3395), also known as algestone 16ñ,17ñ-acetonide or 16ñ,17ñ-isopropylidenedioxyprogesterone, is a progestin which was never marketed. It is the acetonide cyclic ketal of algestone. Another progestin, algestone acetophenide, in contrast, has been marketed.