Metribolone, (also known as methyltrienolone or R1881) is a potent, non-aromatizable androgen which has also been used as a photoaffinity label for the androgen receptor.It is the 17-methylated derivative of trenbolone, and is a similarly potent anabolic steroid, but with high hepatotoxicity.

11 members of the Greek national weightlifting team and 4 Greek track and field athletes tested positive with methyltrienolone prior to the 2008 Beijing Olympic Games.