Part of Anderson Silva's defense in a steroid case with the Nevada Athletic Commission (NAC) will be that his use of "sexual performance" medication tainted his drug test result.

Silva will go before the NAC for a disciplinary hearing Thursday following multiple failed tests -- in and out of competition -- for performance-enhancing drugs in January. The former UFC middleweight champion is denying he knowingly took any kind of steroids, but part of his defense will be that sexual performance medication and another supplement contaminated the test results, according to the answer to the NAC complaint obtained Tuesday by MMAFighting.com.

Combate was the first to report the information.

"The Spider" tested positive for drostanolone metabolites twice -- once the day of his Jan. 31 fight against Nick Diaz and in an out-of-competition, Jan. 9 test. Silva also tested positive for androstane, another banned substance, in the random, pre-fight test.

Silva's lawyer Michael Alonso writes in the answer that Silva was "administering or using a supplement for the purpose of enhancing sexual performance and testing of the supplement revealed that the supplement was contaminated with an Exogenous Anabolic Agent: Drostanolone metabolite."

Alonso also wrote that another supplement Silva was taking could have contained androstane.

Silva's defense against the NAC will also contain inconsistencies in drug tests, including two tests -- one pre-fight and one post-fight -- that Silva passed. The NAC did not include in its initial complaint the post-fight test that Silva had passed, according to the answer to the complaint.

Silva also tested positive for temazepam and oxazepam, which are classified as benzodiazepines and not prohibited for in-competition use by the NAC unless there is an exemption given. The commission alleges also that Silva did not inform it about any such supplements in a pre-fight questionnaire.

Alonso writes that the NAC has failed to provide sufficient facts with regards to that part of the claim. Temazepam is commonly used as a sleep aid, while oxazepam is an anti-anxiety medication.

Silva's defense team is asking that the NAC take no disciplinary action against Silva, including any kind of fine or suspension. Silva's team is also asking for the NAC not to overturn the fight result to a no contest. Silva beat Diaz via unanimous decision.

Silva is currently under temporary suspension pending the results of this disciplinary hearing.

Silva, 40, is regarded as the best pound-for-pound fighter in UFC history. He defended the middleweight title 10 times and won 16 straight fights in the organization, both records.

The fight against Diaz was his first in 13 months following a gruesome broken leg he sustained while fighting Chris Weidman in December 2013.