Anderson Silva is sticking to his guns when it comes to his potential anti-doping violation.

Silva has to prove his innocence to the U.S. Anti-Doping Agency (USADA) if he hopes to avoid a lengthy suspension. “The Spider” was flagged by USADA, which forced him off the UFC Shanghai card. He was going to meet Kelvin Gastelum.

This isn’t the first time Silva has been popped for banned substances. He tested positive for Drostanolone and Androstane back in Jan. 2015. The tests reversed his win over Nick Diaz to a no contest.

Speaking to TMZ Sports, Silva said he’s never knowingly taken banned substances:

“Nothing, never in my life, Because, first of all, my body never changed. Sometimes, the problem is – you use a different supplement and this (happens).”