There's an issue for me with some members asking if they can use X cos they work for Y or compete in Z. Whether you work for the military, are contracted to fight in MMA or fly planes - you'll have better access than we do to what you can use or can't. You can use employee reps or just ask - in the case of the army etc it's in the Military Code.
As often, but it's a common sense reply, is those who are drug tested at work. 99.99%of companies that do this test are, in essence, only concerned with your ability to function. In basic terms they don't want you to be high. Sarms wont get you 'high'. Most PEDs, more so at low levels, should not affect your temperament and therefore your ability to fly. I'd imagine a few of the more mature pilots might be on TRT (medically prescribed).