Demetrious Johnson on USADA: 'I don't know what's on the banned substance list'

LOS ANGELES -- There's been a common theme in recent months when news has emerged about potential violations of the UFC's anti-doping policy, administered by USADA: Fighters who are flagged claim they didn't know they were taking something that was on the banned substance list.
The unregulated supplement industry is usually at the center of these situations. Yoel Romero recently had a potential two-year violation suspension negotiated down to six months, while Lyoto Machida just last week self-r