In the wake of Russian tennis superstar Maria Sharapova’s admission to testing positive for recently banned substance meldonium, the drug’s uses and effect on athletes and laypeople has come under the microscope during the week and prompted debate as to whether it can enhance athletic performance.

However, the drug’s creator has recently been far more grave over the ban on the substance.

Created in the early 1970s by Ivars Kalvins, the chairman of the scientific board of the Latvian Institute of Organic Synthesis, meldonium was first intended to work on livestock; later, Russia, then part of the Soviet Union, hoped it could elevate the performance of soldiers during its conflict with Afghanistan in the 1980s, according to Wired.

The drug was at first used to treat heart ailments like arrhythmia and atherosclerosis. It helps the body take on more oxygen at a more efficient rate so as to help rehabilitation and even stamina.

As the New York Times broke down, meldonium — often sold under the brand name mildronate, as Sharapova claims she knew it — allows the body to burn more glucose for more energy. It does so by limiting the creation of carnitine, an amino acid derivative and nutrient that helps the body burn fat.

It’s for that reason many, including the World Anti-Doping Agency, which put meldonium on its banned substance list in January, believe the substance can be used to help athletic performance.

Prior to the ban, it became clear to WADA that meldonium was becoming widespread among athletes. Last year, the Partnership for Clean Competition, a nonprofit group formed by the U.S. Anti-Doping Agency, the U.S. Olympic Committee and other sports leagues, conducted a study of urine samples from 8,300 athletes from many sports; 182, or a very high 2.2 percent, tested positive for meldonium.

The ban on meldonium has particularly struck Russian athletes. Since Sharapova’s announcement, seven Russian athletes have reportedly tested positive for the drug and the number could rise. German broadcaster ARD reportedly uncovered last year that of 4,316 samples taken from Russian athletes, 724, or 17 percent, contained meldonium.

The drug is also widely available over the counter in Russia and Eastern Europe, going for as little as $3 to $10 for 40 capsules, according to the Times. It has not been approved by the Food and Drug Administration, and thus is illegal in the United States.

Since it is so widely used by both athletes and the public at large in Russia, Kalvins told BBC Radio 5 that he fears the ban could lead to the death of many athletes.

“We will see many deaths on the field,” Kalvins told BBC Radio 5. “Athletes who use mildronate will not be able to do it in the future and will be not more protected.”

Kalvins also said: “This drug was on the market for 32 years — as a self-protective agent — and now suddenly it becomes forbidden. You could see a sudden death in the sports events sometimes.”