Metabolic & Weight Management

Leptin

Leptin is the hormone fat tissue releases to tell the brain how much energy is stored, and its discovery is what reclassified body fat from inert padding to an endocrine organ. What it does when it is missing and then restored is on file in one striking measurement: in eight women with lipodystrophy and almost no leptin of their own, the energy needed to reach fullness from a standardised food array fell from 2,034 to 1,135 kcal over four months of injections. That is also the boundary of its established use. The manufactured version, metreleptin, is approved as replacement for generalised lipodystrophy and leptin deficiency, both rare, and for ordinary weight management the record holds one randomised trial of leptin combined with pramlintide.

Last updated 12 August 2026

Studied forAppetite regulation research · Lipodystrophy replacement therapy · Insulin sensitivity context

Evidence on file1 randomised human trial · 1 human observational study

Strongest sourceNCT00392925: A Phase 2A, Randomized, Controlled, Double-Blind, Multicenter Study to Evaluate the Safety, Tole… (randomised human trial)

Mechanism

Activates the long-form leptin receptor in the hypothalamus through JAK/STAT signalling, reducing appetite and altering energy expenditure.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

Appetite regulation research
Lipodystrophy replacement therapy
Insulin sensitivity context

Dosing on file unverified

Metreleptin: 0.01-0.24 mg/kg/day titrated; PEG-OB: 20 mg weekly

Carried from a source that labels it unverified, and reproduced with that label attached. A record of what is reported, not a recommendation. No citation on this page establishes it.

Half-life, storage & sport

Elimination half-life: 26 min (mice, SC) — study. Frontiers in pharmacology 2026; mice; baseline figure for unmodified leptin, restated by this review from Morath et al. 2015.

The half-life on file is 26 min, measured subcutaneously in mice. On the schedule this record states — daily — each dose has fallen to under 0.1% of its own peak by the time the next is given. Nothing accumulates, and there is no loading phase to run.

Dosed daily over 4 d, each dose normalised to the first peak.

The measurement is not human. It was made in mice, and small mammals clear peptides faster than people do — so this is the fastest plausible shape rather than the expected one.

The rise is not modelled and the axis is not a blood level. No absorption rate constant and no volume of distribution are on file, so each dose appears at full height the instant it is given, and the axis is percent of this compound's own peak.

Literature on file 3

human RCT
NCT00392925: A Phase 2A, Randomized, Controlled, Double-Blind, Multicenter Study to Evaluate the Safety, Tolerability, and Effect on Body Weight of Recombinant-Methionyl Human Leptin Administered in Conjunction With Pramlintide in Overweight and Obese Subjects graded on: a randomised study — “Randomized, Controlled, Double-Blind, Multicenter Study”
human observational
Serum Immunoreactive-Leptin Concentrations in Normal-Weight and Obese Humans (New England Journal of Medicine 1996, cited 4650x) graded on: cross-sectional serum leptin in 136 normal-weight vs 139 obese subjects — read from the abstract — “abstract review”
review or editorial
Leptin and the regulation of body weight in mammals (Nature 1998, cited 4058x) graded on: indexed as "Review" - secondary literature, not a study — “Review”

Identity

Space-filling 3D model of Leptin, carbon grey, nitrogen blue, oxygen red — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

2D chemical structure of Leptin — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

Molecular weight: 2004.3
Molecular formula: C87H138N22O28S2
CAS number: 177404-21-6
PubChem CID: 157010069
InChI key: NRYBAZVQPHGZNS-ZSOCWYAHSA-N
Sequence: VPIQKVQDDTKTLIKTIVTRINDISHTQSVSSKQKVTGLDFIPGLHPILTLSKMDQTLAVYQQILTSMPSRNVIQISNDLENLRDLLHVLAFSKSCHLPWASGLETLDSLGGVLEASGYSTEVVALSRLQGSLQDMLWQLDLSPGC
SMILES: CC(C)C[C@@H](C(=N[C@@H](CCC(=N)O)C(=NCC(=N[C@@H](CO)C(=N[C@@H](CC(C)C)C(=N[C@@H](CCC(=N)O)C(=N[C@@H](CC(=O)O)C(=N[C@@H](CCSC)C(=N[C@@H](CC(C)C)C(=N[C@@H](CC1=CNC2=CC=CC=C21)C(=N[C@@H](CCC(=N)O)C(=N[C@@H](CC(C)C)C(=N[C@@H](CC(=O)O)C(=N[C@@H](CC(C)C)C(=N[C@@H](CO)C(=O)N3CCC[C@H]3C(=NCC(=N[C@@H](CS)C(=O)O)O)O)O)O)O)O)O)O)O)O)O)O)O)O)O)O)N
InChI: InChI=1S/C87H138N22O28S2/c1-41(2)27-48(88)72(121)97-50(18-21-65(89)112)73(122)93-36-68(115)95-61(38-110)84(133)104-54(28-42(3)4)77(126)98-52(20-23-67(91)114)75(124)106-59(33-70(117)118)82(131)100-53(24-26-139-11)76(125)102-55(29-43(5)6)78(127)105-58(32-46-35-92-49-16-13-12-15-47(46)49)81(130)99-51(19-22-66(90)113)74(123)101-56(30-44(7)8)79(128)107-60(34-71(119)120)83(132)103-57(31-45(9)10)80(129)108-62(39-111)86(135)109-25-14-17-64(109)85(134)94-37-69(116)96-63(40-138)87(136)137/h12-13,15-16,35,41-45,48,50-64,92,110-111,138H,14,17-34,36-40,88H2,1-11H3,(H2,89,112)(H2,90,113)(H2,91,114)(H,93,122)(H,94,134)(H,95,115)(H,96,116)(H,97,121)(H,98,126)(H,99,130)(H,100,131)(H,101,123)(H,102,125)(H,103,132)(H,104,133)(H,105,127)(H,106,124)(H,107,128)(H,108,129)(H,117,118)(H,119,120)(H,136,137)/t48-,50-,51-,52-,53-,54-,55-,56-,57-,58-,59-,60-,61-,62-,63-,64-/m0/s1

Notes unverified prose

FDA-approved (metreleptin); Myalept PI; NCT00392925; Metreleptin FDA-approved (Myalept)

Not on file 0

All 8 tracked fields hold a value on this record: molecular weight and formula, CAS number, PubChem CID, amino-acid sequence, SMILES, InChI and InChI key.

Counted from the record itself, not from what a source said it was missing. 163 of 188 records still have at least one empty.

Listed prices 6

What 3 shops we track listed for Leptin, read from their own public catalogues on 2026-09-14. We take no commission on these and they are not ranked by any payment — how vendors are scored.

Compare prices6 listings from 3 shops

Listed in CAD
Vendor	Size	Price	Per mg
Buy Peptides 4 Research Canada	1 mg	$29.99 CAD	$29.99/mg
Buy Peptides 4 Research Canada	1 mg	$49.99 CAD	$49.99/mg
Buy Peptides 4 Research Canada	1 mg	$74.99 CAD	$74.99/mg
Buy Peptides 4 Research Canada	1 mg	$94.99 CAD	$94.99/mg

Listed in USD
Vendor	Size	Price	Per mg
PureRawz ships worldwide	2 mg	$126.24 USD	$63.12/mg
Behemoth Labz	2 mg	$133.25 USD	$66.63/mg

Prices are the vendor's own listing, reproduced with the date we read it — never converted between currencies, and compared per milligram only where the vendor states the vial size.

At a glance

Strongest rung: human RCT
Citations: 3
Regulatory: In or past clinical trials (verified)
Route: Subcutaneous
Declared gaps: 0

Citations by rung

Strongest wins, never an average.