Though Masteron holds a weaker androgenic strength rating than Testosterone itself, androgenic side effects are still indeed possible with this compound, especially among those who may be particularly sensitive. Masteron side effects that include androgenic side effects include: an increase in oily skin (as a result of increased sebum production/secretion), increased facial hair and bodily hair growth, as well as the increased risk of triggering MPB (Male Pattern Baldness) in those that are genetically sensitive or predisposed to it. Virilization (the development of male characteristics in women) is also a risk with female use, though its use in female breast cancer patients should attest to its acceptable nature as a female-use compound.
Stephan Bonnar and Josh Barnett , mixed martial arts (MMA) fighters from the UFC and PRIDE Fighting Championships , have also tested positive for the banned substance.  After the World Extreme Cagefighting show on January 20, 2006 Muay Thai turned MMA fighter Kit Cope also tested positive for boldenone.  Following the Strikeforce card on June 22, 2007 former PRIDE and UFC fighter Phil Baroni tested positive for boldenone, as well as stanozolol .  At a K-1 WGP event in Las Vegas on August 17, 2007 two fighters, Rickard Nordstrand and Zabit Samedov , both tested positive for boldenone.  Alexandre Franca Nogueira tested positive for boldenone in July 2008.