Why is it illegal? Are drugs illegal by default or has it been specifically controlled/scheduled?
I looked up which drugs are scheduled in the UK and found the list is about 100x longer than I thought it was and in fact the government don't even publish a definitive and exhaustive list of all substances.
At least in the UK, drugs are legal by default in the sense that a specific chemical has to be classified under the misuse of drugs act to be a "drug".
However, specific classes of drugs (synthetic cannabinoids and substituted phenylethylamines etc.) are banned in their entirety by designer drug legislation. This is to stop people producing stuff like mephedrone etc., because there's an almost endless potential for minor chemical substitutions while still retaining the effects.
AFAIK peptides are not covered by any of that legislation, so they are a grey area, hence why they get sold as "research chemicals" "not for human use" etc. Separately it's probably illegal to produce patented drugs like semaglutide through non-official channels, but that would be a civil/commercial matter, not a drugs offence per se
Well for one they're flying in the face of the patent protection in place for Retatrutide -- that said the legalities around distributing prescription drugs or unknown chemical substances is murky (hence "gray" market).
I looked up which drugs are scheduled in the UK and found the list is about 100x longer than I thought it was and in fact the government don't even publish a definitive and exhaustive list of all substances.