An update on the Park Tae-hwan story that’s continuing to develop this week: South Korea’s Arirang News reports that Park’s positive drug test was the result of a Nebido injection.

It had been reported earlier in the week that Park failed a doping test after getting an injection at a chiropractic treatment, and would face a hearing in February.

Now it’s being reported that the injection Park received was Nebido, a commercial brand of the substance testosterone undecanoate, an ether of the male body’s testosterone.

The website for Nebido plugs the drug as a treatment for testosterone deficiency, and it doesn’t appear the drug has any other recognized medical uses besides treating those whose bodies don’t have a healthy amount of testosterone.

The Nebido website also features a section warning doctors that “Androgens like Nebido are not suitable for enhancing muscular development in healthy individuals or for increasing physical ability.”

Park has so far alleged that he asked the doctor who gave him the injection whether it was legal, and was given false assurance that it contained no banned substances.