Selective androgen receptor modulators, or SARMs, mimic effects of testosterone
"There are serious potential side effects," researcher says
Selective androgen receptor modulators, known as SARMs, are pharmaceutical drugs that mimic the effects of testosterone. Not yet approved by the US Food and Drug Administration, these compounds are often marketed to bodybuilders online as “legal steroids” that can help them look leaner and more muscular.
Most of the products sold online as SARMs contain either these unapproved substances alone – sometimes in amounts different from what is specified on the label – or other unapproved hormones and steroids, according to a study published Tuesday in the medical journal JAMA.
“There are serious potential side effects, and there’s this wide-held misperception that these compounds are safe,” said Dr. Shalender Bhasin, co-author of the new study and director of the research program in men’s health at Brigham and Women’s Hospital.
About a dozen pharmaceutical companies have been developing SARMs since the mid-1990s, Bhasin explained. Designed to help people with diseases such as muscle wasting, they are intended to have beneficial effects similar to those of testosterone, which can increase muscle and energy, without negative side effects such as blood clots and enlarged prostate.
Some SARMs have undergone limited human testing, but others have not, so their overall safety and efficacy remains unknown, Bhasin said. Still, early research has shown that in large doses, they can suppress natural production of testosterone and induce infertility. They also might have psychiatric side effects, including mania and suicidality.
Life-threatening reactions, including liver toxicity, have occurred in people taking SARMs, which also have the potential to increase the risk of heart attack and stroke, according to the FDA.
“Young men, almost exclusively young men, they’re using these compounds to improve their appearance,” Bhasin said.
He collaborated with researchers from the US Anti-Doping Agency and the Uniformed Services University of the Health Sciences to conduct the new study, which began with a simple Google search.
Testing the products
Common names for SARMs include ostarine, andarine, RA140, ibutamoren, GW501516 and SR9009. Searching for these terms online, Bhasin and his colleagues found more than 210 products, most of which were either out of stock or unavailable. However, the research team was able to purchase 44 drugs that they evaluated using the World Anti-Doping Agency’s approved chemical analysis procedures.
About half – 23 products – contained SARMs. An additional 17 products (39%) contained one or another unapproved drug, such as growth hormones or steroids, that have been banned by the anti-doping agency.
Meanwhile, only 18 of the 44 had an active compound that matched what was listed on the label, and a quarter of the products had detectable amounts of the listed compound at a different amount than stated on the label. In eight products, label ingredients remained undetectable.
When he first heard the “unsubstantiated reports of SARMs and other appearance- and performance-enhancing drugs” being sold online, he was “incredulous,” Bhasin said.
Regulation and enforcement
“The whole basis of commerce is that you buy something either on the internet or in a store, and it has a label that shows what is in the container, and it tells you what the product is and how much is being sold,” Bhasin said. “Just imagine, you go to the grocery store and you want to buy baby food for your children” – but the contents are not what the label says, or “worse, it contains something else whose safety is unknown.”
Drs. Richard J. Auchus and Kirk J. Brower of the University of Michigan wrote in an editorial that accompanies the new study, “How can these pharmaceutical agents be widely available to the public without FDA approval, prescription, or manufacturing oversight?”
“Rapid developments in information technology, consumerism, medicine, and public policy” all play a role in the availability of these substances, explained Auchus and Brower, who were not involved in the new study.
Noting that the 1994 Dietary Supplement Health and Education Act exempted products classified as “dietary supplements” from rigorous studies prior to marketing, the “result was a flood of unregulated” products. Androgens (male hormones) were “aggressively marketed as supplements, even though these compounds are drugs and not food,” Auchus and Brower wrote. Many “so-called dietary supplements still contain hormones, drugs, and known toxins often not listed on the label,” they wrote.
Who is responsible for clamping down on these products?
Although the FDA is duty-bound to take action against adulterated or misbranded dietary supplements after they reach market, the agency “does not have the resources to address all of these cases,” Auchus and Brower noted.
The FDA recently issued warning letters to three companies for distributing products that contain SARMs. Marketed and labeled as dietary supplements, the products are actually unapp