An arbitrator for the Horseracing Integrity and Welfare Unit has used evidence drawn from the testing of hair samples to lengthen a suspension given to a trainer for a violation of the rules for the use of clenbuterol, a strictly regulated bronchial dilator that can build muscle mass when used regularly.
Efren Loza Jr., a trainer based in Florida, had four years tacked on to his initial suspension as part of the arbitrator’s ruling, which counted the evidence collected from the hair analysis as a second violation of the banned substance rule. Loza was also fined $30,000 and was assessed an $8,000 penalty for the costs of arbitration.
The case is the third prominent example of HIWU using hair testing in the adjudication of positives and the second to use out-of-competition hair sampling for clenbuterol violations. In late 2024, HIWU used hair samples from out-of-competition testing for multiple horses trained by Francisco Ramos after blood testing revealed clenbuterol in the samples from other horses under Ramos’s care.
In early 2024, HIWU used hair samples to clear trainer Jeffrey Engelhart, dropping its case after hair testing revealed that the drug could not have been administered while in Engelhart’s care.
According to the arbitrator’s ruling, HIWU conducted out-of-competition testing on horses previously trained by Loza after he had been issued a suspension for a different clenbuterol positive. Although the horse, named Lucago, was not in Loza’s care at the time the sample was pulled, the hair testing indicated that the horse began receiving administrations of the drug while Loza was the “covered person” responsible for the horse.
Hair testing can be used to detect violations for a range of drugs because evidence of the drug use shows up in hair strands far longer than other biological samples. Because hair grows at known rates, the dates of administration can be estimated based on the segment of the hair where the evidence of the drug shows up.
In Lucago’s case, the evidence presented during the arbitration hearing found highly elevated concentrations of clenbuterol in the hair sample going back to five months prior to the out-of-competition sample being pulled.
“Based on sound scientific reasoning – and common sense – Lucago’s exposure to clenbuterol had to have occurred prior to June 3, 2024,” when the horse was transferred to a different trainer, the arbitrator ruled.
Regulators began cracking down on clenbuterol use decades ago, but rumors have persisted that the drug is still being used in micro-doses on horses in training to benefit from clenbuterol’s anabolic effects when used regularly. Loza had argued that the positive tests were the result of accidental contamination, a contention that the arbitrator, Nancy Holz, dismissed based on the evidence from the hair testing.
“Mr. Loza only speculates and has not provided any concrete evidence to substantiate this theory,” Holz wrote. “He has not identified a specific source of the alleged contamination, nor has he presented any expert analysis or documentation supporting how or when such contamination could have occurred or establishing that it can be considered low.”
Loza has not started a horse since June 2024, when his first suspension began. Although he started more than 100 horses per year from 2014-2017, his number of starts had dropped precipitously in recent years. He had three wins from six starts in 2024. For his career, he has won 226 races from 770 starts for an overall win rate of 29 percent.
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