What Would Happen If You Took Meldonium?

Meldonium is used in heart disease therapy. Donat Sorokin / TASS / Getty Images

Russian tennis phenom Maria Sharapova instantly made a drug called meldonium famous with her recent drug-test fail. More than a hundred other international athletes have also been busted for this newly banned substance, but Sharapova’s star cred put the purported heart drug on the map. Now that so many pros have been called out, doctors worry that meldonium will make its way to amateurs looking to gain an edge. “With this drug’s new visibility, a lot of people are going try it,” says Dr. Paul D. Thompson, chief of cardiology at the Hartford Hospital in Connecticut. “We’re going to learn a lot about meldonium’s side effects very quickly.” Here's why you should think twice about being the first guinea pig. 

Meldonium, also known as mildronate, was discovered by a Latvian chemist in the 1970s and purported to have cardiovascular benefits. The problem: There’s very little published research demonstrating its efficacy or safety. Most of the studies have been conducted on rodents, and the one noteworthy human trial was still too small and too short to yield any definitive answers. Due to the dearth of evidence, meldonium is not approved by the FDA or in the European Union. It’s primarily used in Russia, Ukraine, and Eastern Europe, where it’s sold over-the-counter.

Although many questions remain about the drug, it does seem to have a clear mechanism of action, which could help both the heart and athletic performance. According to Karen Kopacek, associate professor of pharmacy at the University of Wisconsin-Madison, meldonium appears to inhibit a substance in the body called l-carnitine. Normally, l-carnitine transports fatty acids to the mitochondria, where they are burned for energy. “But by blocking the availability of l-carnitine, meldonium forces your mitochondria to metabolize glucose for energy instead, which requires less oxygen,” she explains. This decreases oxidative stress and cellular damage while making your body use energy more efficiently.

For these reasons, Kopacek says it’s possible that meldonium enhances athletic performance and shortens recovery time after workouts. But again, this is all gleaned from animal studies and other poor-quality trials, so she insists there’s no guarantee.

Whether it works or not, doctors know virtually nothing about its potential side effects. In the handful of published studies on humans, none have been reported. “It makes me leery that a trial could go on for 12 weeks and the researchers don’t note any side effects,” says Kopacek. “Does this mean meldonium doesn’t have any?” Doubtful, she says, since nearly every drug has a side effect of some kind. With meldonium, we just don’t know what they are.

Another unknown is how meldonium interacts with other drugs. The published research also lacks any information on this crucial issue. “Heart disease patients — who this drug is intended for — often take multiple medications, as well as over-the-counter drugs, herbs, and other supplements,” Kopacek says. “You always have to know how these multiple therapies interact, and with meldonium, we have no idea. Yet another reason why I would never recommend this drug.”

Given the FDA’s strict protocol for evaluating and approving drugs for sale, it’s highly unlikely that meldonium — a medication that’s sat idle for decades without much interest from doctors or drug companies — will ever get green-lit in the U.S. “It would require randomized, double-blind, placebo-controlled studies, which cost money,” Thompson says. “Trials would have to be funded by the government, and the National Institutes of Health is not normally interested in helping athletes make more money.” But that's not stopping the booming demand for the drug in Russia. The bottom line: If it does illicitly make its way to your locker room, don't be the first to try it.