It’s a way to get the same medicine just through different suppliers and circumventing various restrictions/regulations, and then prepared by the compounding pharmacy for ingestion by the patient.
Common use cases are, in animals for example, you might need to put a dog a medication and the supplier may not manufacture the right size dose (or maybe your animal won’t eat pills so the compounding pharmacy reformulates it into a liquid)
My veterinarian recommended sticking with brand name meds for my dog even though I was having trouble due to the size of the pill. Her reasoning was compounded equivalents simply aren’t tested in any medical or academic trials, only brand name formulations are tested in trials, so there’s no guarantee of efficacy since you’re literally taking a formulation of a medication that has gone through zero scientific testing (the isolated ingredients or a similar formula may have trials and testing, but not the exact formula you’re taking)
Which is also why no compounded drug can be FDA approved.
Logically I want to trust compounding pharmacies and I want to believe the efficacY and side effects are equivalent to name brand.
But the fact that my veterinarian cautioned me against compounding my dog’s medicine gave me pause about compounding medicine for myself…
After that, I decided to just allow nature to take its course on my hairline.
Lots of drugs are bad for pregnant and/or nursing women. Propecia is not particularly special in this regard, nor is it especially dangerous compared to all the other drugs out there which are also bad for pregnant women.
"Do not handle" is a warning for topical formulations, just because those are intended to be absorbed transdermally.