Head to head
Metreleptin against Setmelanotide
Two approved drugs for rare metabolic disease that are easy to confuse because both work on the pathway that links fat stores to appetite. One replaces a missing hormone; the other activates a receptor downstream of it. Which one applies depends entirely on genotype.
Column A
MetreleptinMetreleptin (Myalept), recombinant human leptin analogue
Transformative in people who make almost no leptin, and useless for ordinary obesity. The clearest case on this site of a hormone that only works as replacement.
Column B
SetmelanotideSetmelanotide (MC4R agonist)
An FDA-approved MC4R agonist for rare genetic forms of obesity driven by defects in the melanocortin pathway.
Side by side, on the facts we can check
| Attribute | Metreleptin | Setmelanotide |
|---|---|---|
| Category | Hormone | Melanocortin |
| FDA status | FDA-approved as Myalept for complications of leptin deficiency in generalised lipodystrophy. Carries a boxed warning for anti-metreleptin antibodies with neutralising activity and for T-cell lymphoma risk, and is subject to a restricted distribution programme. Not approved for obesity or partial lipodystrophy. | FDA-approved (Imcivree) for specific genetic obesity indications |
| Half-life | Roughly three to four hours after subcutaneous injection, which is why it is dosed daily. | ~11 hours |
| Molecular weight | 16.2 kDa. A 147-amino-acid recombinant protein. | 1,117.3 Da |
| Mechanism | A recombinant analogue of human leptin, differing by an added methionine residue. Leptin is secreted by adipocytes in proportion to fat mass and acts at the leptin receptor on hypothalamic arcuate nucleus neurons, suppressing the orexigenic neuropeptide Y and agouti-related peptide neurons and stimulating the anorexigenic pro-opiomelanocortin neurons. It also signals nutritional sufficiency to the reproductive, thyroid and immune axes. In leptin deficiency all those signals read as starvation regardless of actual energy stores, which is why replacement does so much. In ordinary obesity leptin is already elevated and central resistance has developed, so adding more changes little. | Selectively agonizes the melanocortin-4 receptor (MC4R) to restore satiety signaling disrupted by upstream genetic defects. |
| Human studies cited | 1 | 2 |
| Legal status, US | FDA-approved, prescription only | FDA-approved, prescription only |
Frequently asked questions
What is the difference between Metreleptin and Setmelanotide?
Metreleptin: Transformative in people who make almost no leptin, and useless for ordinary obesity. The clearest case on this site of a hormone that only works as replacement. Setmelanotide: An FDA-approved MC4R agonist for rare genetic forms of obesity driven by defects in the melanocortin pathway.
Which has stronger research evidence, Metreleptin or Setmelanotide?
This database does not grade compounds. It counts what was run in people: 1 of the 1 studies cited on the Metreleptin profile were human work, against 2 of 3 for Setmelanotide. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Metreleptin and Setmelanotide FDA-approved?
Metreleptin: FDA-approved as Myalept for complications of leptin deficiency in generalised lipodystrophy. Carries a boxed warning for anti-metreleptin antibodies with neutralising activity and for T-cell lymphoma risk, and is subject to a restricted distribution programme. Not approved for obesity or partial lipodystrophy.. Setmelanotide: FDA-approved (Imcivree) for specific genetic obesity indications.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.