Ostarine 101: The Drug Behind Recent Positive Tests

A look at the short history of ostarine—plus what you can do to make sure you don’t inadvertently ingest it (or another banned substance). 

Chances are you hadn’t heard of ostarine a few weeks ago. If you follow triathlon closely, it’s almost certain that you’ve heard of it now. News broke on Feb. 3 that American triathletes Beth Gerdes and Lauren Barnett had both tested positive for the banned substance. Barnett was able to prove that her positive test was the result of a contaminated salt tab and had her ban reduced to just six months. Gerdes was not able to provide the same level of definitive proof and was handed a two-year suspension. Here’s the DL on the muscle builder.

What is ostarine?

Ostarine, also known by its generic name enobosarm, falls into a class of drugs called Selective Androgen Receptor Modulators, or SARMs. It was originally developed by pharmaceutical giant Merkcx, but is now developed by GTx Inc., a much smaller pharma company based in Memphis that specializes in hormone receptor modulators. It’s currently being researched for its ability to combat muscle and bone wasting related to diseases like osteoporosis and muscular dystrophy, or due to chemotherapy in cancer patients. It’s a powerful drug and it has shown promise to produce results similar to anabolic steroids without a laundry list of dangerous side effects. It was banned by the World Anti-Doping Agency in 2008, and since then at least a dozen positive tests have been reported in sports ranging from mixed martial arts to triathlon.

The contamination issue

It’s nothing new to find dietary supplements contaminated with pharmaceutical drugs. Pharmaceutical drugs and dietary supplements are both regulated by the FDA, but because supplements are considered “special foods” instead of drugs, they’re not subject to the same strict safety and efficacy standards. Basically, drugs are considered harmful until they can be proven safe, while supplements are considered safe until they can be proven harmful.

While GTx owns a patent for ostarine and continues to perform research trials in hopes that it will gain FDA approval, a number of supplement manufacturers have began manufacturing their own enobosarm compounds and marketing them on the internet. The FDA’s Office of Criminal Investigations began cracking down on supplement companies selling ostarine online, and GTx has pursued legal action against a number of such companies, but the problem persists and supplements containing ostarine are still relatively easy to purchase online. With a quick Google search and a PayPal account, you could have ostarine at your doorstep in less than a week.

The problem for professional athletes is that most supplements aren’t manufactured by the companies that ultimately sell and market them. It’s simply not economical for a small supplement company to own and operate its own equipment. Instead, they outsource to a contract lab (many of which are based in Utah) and tell that lab what raw ingredients they want included in a specific supplement. The lab then sources those ingredients from a number of suppliers, turns them into a capsule, tablet or powder, and a new supplement is born. Contamination becomes an issue when a seemingly “safe” supplement (like a salt tab) is manufactured with the same equipment that produces a supplement containing a banned substance (like ostarine). It’s rare for such contamination to trigger a positive test in an athlete, but because of the extreme lack of regulations for supplement manufacturers, it’s not unheard of.

Gerdes and Barnett

Upon learning of her positive test in August of last year, Barnett provided both open and unopened samples to WTC of a salt supplement she had taken for testing. While Barnett did not reveal the name of the supplement (because it could affect any potential legal action on her part) it is worth noting that an electrolyte supplement contaminated with ostarine did appear on USADA’s 411 High Risk List on the same day that news of Barnett’s positive test became public. Because the WADA-accredited lab found the presence of ostarine, Barnett’s ban was reduced to only six months. While it’s the absolute minimum punishment for an athlete with a positive test—and it essentially amounted to time-served while she was resolving the issue—it was still understandably difficult for Barnett to take.

“Is it right that the responsibility rests solely on the athlete? Or should companies be held accountable as well,” Barnett says. “What I went through, I believe, was completely out of proportion to any violation of the rules. Was the heartache, the turmoil, the grief—not to mention the financial investment to uncover the truth and the loss of opportunities to race—justified? Absolutely not. But because there have been dishonest athletes that have come before, an environment has been created in which the honest athletes are left with zero room for marginal unintentional error.”

In a blog post from Feb. 7, Gerdes stated that the salt supplement she was taking was different from Barnett. Her A and B urine samples taken after Ironman Australia returned positives for a trace amount of ostarine (between 7 and 11 nanograms/ml). In the months following, Gerdes provided multiple samples of every supplement she was taking to an accredited lab in Australia for testing. In November, Gerdes learned that an unopened package of salt tabs she had provided had returned a “presumptive positive” for ostarine. However, two months and two tests later the lab was unable to confirm a high enough level of contamination to confirm the presence of ostarine with 100 percent certainty. After an arbitration hearing with WTC, Gerdes ban was reduced from four years to two years.

Who’s at risk?

One question that has been brought up is why positive tests for ostarine are much more common among female athletes. Aussie pro triathlete Lisa Marangon also tested positive for the substance in 2016 and was given a four-year ban after she could not prove any contamination. One could argue that female athletes are more likely to cheat with ostarine because it is much more effective for women than men. Women produce significantly less androgen than men, and thus supplementing with an androgen-boosting drug would have a much more significant benefit in terms of boosting lean muscle mass in women.

The other argument is that low levels of ostarine resulting from potential supplement contamination would be much harder to detect in male athletes. Drug testing is calibrated for the “normal” levels of a given substance in men or women. The threshold for something like a SARM is significantly lower for female athletes. In theory, a male and female athlete could take the same contaminated salt tabs and the positive test would only show up in the female athlete. Further complicating the testing is that most female athletes are significantly smaller than their male counterparts and therefore the concentration of a substance resulting from low level contamination is greater and more detectable.

Right now, the best thing athletes can do to protect themselves is to only take supplements that have third-party testing certification. The two big organizations that do this kind of testing are NSF Certified for Sport and Informed-Choice, both of which have certified thousands of supplements as free of banned substances. If a supplement doesn’t have one or both of these certifications, think twice about taking it. Even if you’re an age-group athlete with little or no chance of being tested, it’s worth knowing that what you’re taking is exactly what’s printed on the label.