Zearacolol General Information
Zeranol (Zeranol , INN, USAN, BAN) (trade names Frideron, Ralabol, Ralgro, Ralone, Zerano; development code MK-188, P-1496) or zearacol, also known as dextetradecanol Zearalanol , α-zearalanol, is a synthetic nonsteroidal estrogen of the resorcinolactone group, related to fungal estrogens found in fungi of the genus Fusarium , used primarily as an anabolic agent in veterinary medicine.
Zearacol brand
Zearacol is approved in the United States for use as a growth promoter in livestock, including beef cattle, under the brand name Ralgro (manufactured by Merck Animal Health). In Canada, it is only approved for use in beef cattle. Its application is not approved for use in the EU. However, it is sold in Spain under the brand name Ralone.
Although zearacol may increase cancer cell proliferation in existing breast cancers, dietary exposure from the use of zearacol-containing implants in cattle is minimal. Zearacol may be a contaminant in fungal-infected crops. As an estrogen, it is 3 to 4 times more potent than the related compound zearalenone. It is a metabolite of zearalenone.
What is zearacol?
Zearacol is a veterinary drug approved for use in livestock in the United States but is not approved by the U.S. Food and Drug Administration (FDA) for use in humans.
Although zearacol is a legal livestock growth promoter in the United States, the FDA and the U.S. Department of Agriculture (USDA) are also responsible for evaluating the safety of zearacol and regulating its use in agricultural settings. For example, the U.S. Food and Drug Administration (FDA) and U.S. Department of Agriculture (USDA) have established regulations to control the amount of zearalenol used in the livestock industry and have established maximum average daily intakes for zearalenol consumption in humans.
Due to its growth-promoting and presumed anabolic effects in humans, zearacol appears on the WADA Prohibited List, classified as S1.2 Other Anabolic Drugs. It has been tested in routine doping control assays for more than 15 years. Of the millions of urine analyzes conducted and reported by WADA since 2003, only six have come back positive globally. Over the past 15 years, the United States Anti-Doping Agency (USADA) has also conducted more than 100,000 tests and only once came back positive for zearacol.
In response to the global rise in positive test results related to drug and meat contamination, a group of scientific and legal experts have made specific recommendations to WADA for selected diuretics and anabolic steroids/growth promoters detected Establish Minimum Reporting Levels (MRL) for urine samples from WADA-accredited laboratories. Since June 2021, WADA has banned several banned diuretics (i.e. acetazolamide, bumetanide, furosemide, hydrochlorothiazide, torasemide and triamterene) and livestock growth promoters (i.e. gram MRLs have been implemented for Lenterol, ractopamine, zipaterol, and zearacol) and will continue to be implemented to evaluate whether other compounds directly related to contamination require MRLs. For certain sports or in certain circumstances, results below the MRL will trigger an investigation by the relevant anti-doping agency in an attempt to determine the source and circumstances of ingestion or exposure to a prohibited substance. For more information, please see WADA’s statement.
How common are zearacol residues in meat in the United States?
The USDA's Food Safety and Inspection Service (FSIS) monitors levels of various residues in tissues such as muscle and liver through random and targeted sampling. These results are published in the FSIS National Residue Program Red Book. In the most recent publication, only one zeitol residue violation was reported, which occurred in 2014 and involved sows rather than beef cattle.
Is there a way to minimize the risk of a positive drug test for zearacol in the United States?
There is a small risk of testing positive for stimulants from meat contaminated with zearalenol. In the United States, the United States Anti-Doping Agency (USADA) has seen only one positive test for zearacol in sixteen years.
However, if a positive test for zearacol occurs, we will work closely with the athlete, as in the recent case, to thoroughly evaluate whether the positive test may be from zearacol contamination.
