The Horseracing Integrity and Welfare Unit has reduced a penalty for two violations of its prohibited substance policy to a series of fines after determining that a Parx-based trainer bore “no significant fault” for the finding of testosterone in hair samples from two mares in his care. Although trainer J. Guadalupe Guerrero was technically suspended for eight months for the two positives, HIWU backdated the suspensions to the date of the finding of the positives, a time when Guerrero continued to start horses at Parx, according to a summary of the resolution of the case posted by HIWU. Guerrero was fined $2,500 for each of the positives. According to HIWU, during a hearing to adjudicate the positives, Guerrero provided evidence that he had been prescribed a testosterone-containing gel and applied it daily to his arms. Guerrero also said that he had discussed the possibility of inadvertently transferring the gel to his horses with his doctor, and HIWU said that he provided evidence that he washed his arms prior to handling his horses and took other precautions to mitigate the possibilities for cross-contamination. “In this matter, HIWU has determined that, based on the circumstances, Mr. Guerrero has established on a balance of probability that he bears no significant fault or negligence” for the two positive findings, HIWU wrote. :: Access the most trusted data and information in horse racing! DRF Past Performances and Picks are available now. Testosterone, which builds muscle mass, occurs naturally in intact males and in minute concentrations in female horses. The finding of testosterone in a female has a zero-tolerance level under the rules enforced by HIWU.  HIWU said in its summary that Guerrero voluntarily stopped using the gel after being notified of the findings.  Guerrero has started horses as a trainer going back to 1991, but his business picked up in the early 2010s and he started in excess of 200 horses a year from 2022-2025, winning at a rate of approximately 15 percent during that time frame. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.