That led to a lot of questions about what deer-antler spray is and why athletes use it.

Here is an explainer.

What is deer-antler spray?

Deer-antler spray is a substance made of antler extract that you spray under your tongue.

Why do athletes use it?

Athletes take it for the same reasons they take HGH — it builds muscle and makes you bigger, stronger, and faster, according to the companies that make it. It contains IGF-1, which is a natural growth factor that's really similar to HGH.

Won't they test positive?

It's almost impossible to detect in drug tests, so the risk of getting caught is not that high.