Is Neuropeptide Y legal in the United Kingdom?

The most potent appetite-driving peptide known when injected into a rodent brain. The one large human test of the idea, a 52 week trial of a Y5 receptor blocker in 1,661 overweight and obese adults, produced weight loss its own authors called not clinically meaningful. The only trial of NPY itself in people gave it intranasally to 26 patients with PTSD.

Neuropeptide Y is one of the most abundant neuropeptides in the mammalian brain and a co-transmitter released alongside noradrenaline from sympathetic nerves. It is a 36 amino acid peptide and it belongs to one structural family with peptide YY and pancreatic polypeptide, which is why the three are almost always discussed together.

Mechanism: NPY signals through a family of class A G protein-coupled receptors. In humans, Y1, Y2, Y4 and Y5 are functional.

Regulatory history: NPY is an endogenous neuropeptide, not a drug, and there is no approved product containing it. No drug acting at any NPY receptor is approved for obesity or for any other indication. Intranasal NPY has been studied in a phase 1 trial in PTSD.

Licenses medicines for the UK market. A compound without a marketing authorisation is an unlicensed medicine, which can only lawfully be supplied for human use through a prescriber under the specials scheme, not sold as a research product.

The classification above is the The Longevity Archive reading of Medicines and Healthcare products Regulatory Agency listings for Neuropeptide Y at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.