Is Leptin legal in the United Kingdom?

Leptin is a hormone your fat makes. It tells the brain how much energy you have stored. For the rare people born without it, getting it back changes their lives. In ordinary obesity, a 1999 study of 127 people found only small weight loss, and no drug came of it. A version called metreleptin is approved for a rare disease where the body loses its fat, with the FDA's strongest warning on the label.

Leptin comes from fat cells. The more fat you carry, the more leptin you make.

How it works: What we know in people comes from those born without leptin and from giving it back. Leptin docks on a receptor on the brain cells that control hunger.

Approval history: Metreleptin (Myalept) was FDA-approved on 24 February 2014 (BLA 125390, Chiesi). It is used alongside diet to treat problems caused by too little leptin in people with generalised lipodystrophy, a rare condition where the body cannot store fat normally, whether they were born with it or got it later. Listed as Prescription in the FDA drug database (Drugs@FDA) on 11 September 2026. It carries the FDA's strongest (boxed) warning, for antibodies that block metreleptin and for T-cell lymphoma, a blood cancer. It is only handed out through a restricted safety programme (REMS). It is not for use in obesity. Natural leptin is not a product.

Licenses medicines for sale in the UK. A compound without a licence to be sold (a marketing authorisation) is an unlicensed medicine. The law only lets it reach people through a prescriber, under the specials scheme (unlicensed medicines made for one patient's needs). It cannot be sold as a research product.

The legal category above is how The Longevity Archive reads Medicines and Healthcare products Regulatory Agency listings for Leptin on the reviewed date. It is not a legal opinion. Rules change. Bringing a compound into the country, prescribing it and owning it can each be treated differently. Check with the agency before you act on anything here.

Check MHRA directly

Whether Leptin is banned in sport is set by the World Anti-Doping Code and by military rules, not by its legal status in the United Kingdom. Before you compete or get tested, look up Leptin by name on the Prohibited List, or look up a named product in Global DRO. Under the World Anti-Doping Code, category S0 bans, at all times, any drug-like substance that meets two tests. No other section of the List covers it. And no government health regulator anywhere has a current approval for it as a treatment in people. Many substances that are approved somewhere are banned by name in another section. So approval does not mean a substance is allowed in sport.

• WADA Prohibited List
• Global DRO (check a named product)
• USADA (US athletes)
• Operation Supplement Safety (US service members)

The rules you compete or serve under decide this, not this page.