My understanding is by medical standards, the evidence is pretty low quality, which is why GnRH agonists aren't approved by the EMA, MHRA, FDA, or NICE for gender dysphoria.
It highlights a wider issue in medicine though, the obsession with randomised controlled trials, which is basically the only evidence the GRADE method considers "high quality". We are seeing exactly the same problem with MDMA assisted therapy, any therapy where blinding is difficult is dismissed by the medical establishment. NICE dismissed (es)ketamine for depression for the same reason. Add to that the fact that GnRH agonists are off patent, so there's no incentive for industry to fund studies.
You can get the seller to declare it as a gift and put a low value on it.
There's also reshipping services that let you do that, or at least there used to be, it's been a few years since I used one.