On Monday, Golden Boy Promotions issued a statement revealing Canelo Alvarez tested positive for Clenbuterol ahead of his rematch with Gennady Golovkin on May 5.
Per Examine, Clenbuterol is an illegal beta-adrenergic agonist used to beef up livestock (before a metabolite was found to be toxic). It is like ephedrine, except much more potent and stays in your body for a day rather than just 4 hours. It is a potent fat loss and muscle preservation agent with side effects.
Per GBP, there were only trace levels of the drug, which are said to be consistent with meat contamination. This has impacted athletes training in Mexico over the past few years. Per Daniel Eichner, Director of SMRTL, the WADA-accredited lab that conducted the tests, “these values are all within the range of what is expected from meat contamination.”