MY MOM TOOK erythropoietin—EPO. It helped her tired, anemic body pump out more red blood cells for years before it became the drug of choice for professional cyclists in the late 1990s and early 2000s. I mention this because somebody’s mom probably also takes meldonium, the same drug that tennis star Maria Sharapova says she took for a heart condition, but happens also to be on a list of banned performance-enhancing drugs because it boosts athletic endurance and recovery.

In both cases, somebody somewhere figured out that a decent medicine to treat metabolic conditions can also make cyclists pedal uphill faster or give tennis pros a little more energy. This evolution from med to PED (that’s “performance enhancing drug”) has gone on for decades. “What happens is the athletes or athletic community or the athlete grapevine finds out about it,” says John Hoberman, a Germanic studies professor at the University of Texas who has written extensively on the intersection of drugs and sports. “In the past, some cyclists were getting new drugs that weren’t even out of clinical trials yet. The overlap between the therapeutic and the performance enhancing has always been there.”

Since the World Anti-Doping Authority moved meldonium from its “watch list” to its banned list in January 2016, eight competitors have gotten popped—five Russians, two Ukrainians, and a Swedish track world champion.

The move didn’t come out of nowhere. In 2015, the Partnership for Clean Competition, a non-profit alliance of the US Anti-Doping Agency, US Olympic Committee, and several professional sports leagues, funded a study to test for meldonium worldwide. After looking at 8,300 random, anonymous urine tests from athletes in various sports, researchers found traces in 182 samples. “From an anti-doping perspective, the 2.2 percent rate in this study was concerning,” said Larry Bowers, Chair of the PCC Scientific Board, in a statement when the report was released in October 2015. That’s more than twice the rate of positive tests for any single drug on the WADA prohibited list.

But that’s not where it started. Meldonium has a quirky history. The chair of the scientific board of the Latvian Institute of Organic Synthesis, Ivars Kalvins, invented it in the early 1970s for use on livestock, and then scientists there extended its use to humans a decade later. The institute demonstrated meldonium’s ability to treat effects of heart failure, myocardial infarction, arrhythmia, atherosclerosis, and diabetes, as well as how it boosts the sexual prowess of boars. It’s an energy efficiency catalyst that increases oxygen uptake, enhancing stamina and endurance. That’s according to anti-doping officials, who would not speak on the record because the Sharapova case is now pending. The WADA prohibited substances list categorizes meldonium as a “metabolic modulator,” in the same category as insulin.

As good as meldonium is at increasing a person’s metabolism, it’s been pretty great for Latvia’s national metabolism, as well. With sales of 65 million euros in 2013, it’s one of Latvia’s biggest medical exports. The world’s only manufacturer, Grendiks, is based in Riga, Latvia’s capital.

Oh, and! The chair of Grendiks’ board of supervisors, Kirovs Lipmans, is also president of the Latvian Hockey Federation and an executive member of the Latvian Olympic Committee. His dual role as a Latvian sports official and director of a company that produces a performance-enhancing drug raised eyebrows with at least one US anti-doping official. “It’s weird,” says the official, on background.

Furthermore, meldonium isn’t approved by the FDA for sale in the US—where Sharapova lives. At her press conference Monday, Sharapova said she’s been taking the drug since 2006, so she would have likely had to purchase it overseas or through online pharmacies. Without meaning to tar Sharapova with a tenuous association, she’s Russian by birth, and Russia has had major doping scandals—including one so serious that the participation at the Rio Olympics of the entire Russian track team is in jeopardy.

Neither officials at Grendiks nor at the Latvian Institute of Organic Synthesis responded to requests for comment on Tuesday.

It’s probable that somewhere, most likely in Russia or some other former Soviet state, melodium is improving life for elderly cardiac patients, just as EPO helped my mom in her last years. It’s also likely that it won’t be long before another chemist takes a new medicine, tweaks a few molecules and comes up with something even more helpful—that’ll also make a great performance enhancer.