I’ve flown with gear in my shave kit and in diabetic kits never an issue internationally, into USA and out of USA, India, Asia, Europe.
I’ve never flown with excess amounts. Only like peptides in a diabetic chill case, checked in, and vial or two unmarked in a shave kit. I try to never carry a full vial ever.
I’ve never taken on carry on and I would definitely not advise that. TSA would enjoy that. But in luggage my pov is that it’'s not much of a risk.
For international travel I have been stopped, I say I am on TRT and I’ve said I am a diabetic. I have been stopped in USA and I hvae said I have a prescription it is personal use and I am on TRT I am country for a week here is my itinerary, I’ve never taken a SEALED fresh bottle into the USA just enough for a shot or two, they have asked wehre is my prescription I’ve said at home.
If you are going frmo USA to other country I highly doubt anything on flying out, now landing be very carefulw ehre you are going I would NOT ever try to take gear to AUS for example. But you are asking a very wide open question with no info so very hard to advise you.
When in doubt, DON"T, you don’t have the balls to look them in the eye without sweating and say you are on TRT or you are a diabetic or what not then dont risk it. You are taking a risk, but I find the risk of mailing gear to a foreign country could be just as bad as carrying it in depending on the country. For example walking into thai with a vial is a non issue, mailing one in and getting it inspected and held will create you an issue they love to jack up foreigners. The airport customs inspectors there do not have the knowledge to know what is diabetic vs gear if it is one vial with a few oil in it. and if htey seize it you just donate it to them.
YMMV Again when in doubt DONT