Metreleptin (Myalept)_Dosage, benefits & legal status
Also known as Myalept, Myalepta, r-metHuLeptin, recombinant leptin
A recombinant copy of human leptin, injected daily to stand in for the hormone missing in lipodystrophy. Not a weight-loss drug.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Metreleptin (Myalept)?
Plain language first. The technical label stays, but it never stands alone.Overview
People with generalised lipodystrophy have almost no fat, so almost no leptin, and the brain reads that as starvation: constant hunger, severe diabetes and very high triglycerides. In the 48-person NIH study behind the US label, daily injections cut HbA1c by 2.0 points and triglycerides by a median 55% over a year. In ordinary obesity leptin is already high, extra leptin gave only small weight loss, and the label rules that use out.
Metreleptin is a 147-amino-acid copy of human leptin made in E. coli, with an extra methionine at the start (the 'met') and one disulfide bond between cysteines 97 and 147. It activates the leptin receptor, a cytokine-type receptor that signals through JAK/STAT in the hypothalamus and elsewhere. Amgen licensed leptin from Rockefeller University in 1995; it then passed through Amylin, Bristol-Myers Squibb, AstraZeneca, Aegerion and Amryt to Chiesi, its holder since April 2023.
What it's used for
A prescription daily injection, alongside diet, for the complications of leptin deficiency in generalised lipodystrophy (and in the EU, Canada and Japan, some partial lipodystrophy).
How does Metreleptin (Myalept) work?
What it does in the body, and where.Metreleptin replaces leptin, the hormone fat cells use to tell the brain how much energy is stored.
- 01The missing signalFat cells release leptin in proportion to fat mass. With almost no fat, leptin is very low and the brain responds as if starving: hunger rises, and fat spills into the liver and muscle, driving severe insulin resistance.
- 02Replacing itA daily injection restores the signal through the leptin receptor. Appetite falls and insulin sensitivity improves, so blood sugar, triglycerides and liver fat come down.
- 03Why not for obesityIn common obesity leptin is already high: 31.3 against 7.5 ng/mL in normal-weight people in a 1996 study. The brain is relatively resistant to it, so extra leptin gave only small weight loss, and only at high doses.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
Generalised lipodystrophy
FDA-approved- Human trialNIH study, 48 people: HbA1c -2.0 points and triglycerides median -55% at 12 months.
- No dataAll of the evidence comes from open-label studies without a control group.
Longer follow-up
FDA-approved- Human trialNIH cohort, 66 people: HbA1c -2.2 points and triglycerides -32% on average at 12 months; 41% of insulin users stopped insulin.
Partial lipodystrophy
Clinical use- Human trialNIH subgroup of 27: HbA1c -0.9 points and triglycerides -37.4%, smaller effects than in generalised disease.
- No dataMETRE-PL, the first placebo-controlled trial, has not reported results.
Obesity
tested-and-failed- Human trial1999 trial in 127 adults: small, dose-related weight loss needing high doses, with few completers.
- Human trialWith pramlintide, weight loss beat either drug alone, but metreleptin alone did no better than pramlintide alone; the programme ended in 2011.
'HbA1c down 2.2%, triglycerides down 60%' mixes two studies: 2.2 points comes from a 66-patient NIH cohort (59 with HbA1c data) whose triglycerides fell 32% on average, and 60% from a 9-woman pilot. The US label gives 2.0 points and a median 55%. In the US it is approved for generalised lipodystrophy only, with partial lipodystrophy a stated limitation; the EU, Canada and Japan include partial. It is not a weight-loss drug, and the US label contraindicates it in general obesity. Japan approved it first, in 2013. The pramlintide combination's 12.7% weight loss was measured from before a pramlintide lead-in, and metreleptin alone did no better than pramlintide alone. Mature leptin has 146 residues; metreleptin has 147 because of the added methionine. No US partial lipodystrophy filing is under review.
The published record
Papers and trials about Metreleptin (Myalept)
265 papers tagged human · 171 not reviews or lab · 59 clinical trial publications
39 registered trials · 25 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Metreleptin (Myalept)
Evidence
FDA-approved
Category
Weight loss and metabolic
Common vial
11.3 mg
Half-life
3.8 to 4.7 hours
How much, and do you cycle it?
The range, and whether you take breaks.2.5 to 10 mg daily over 40 kg; 0.06 to 0.13 mg/kg at 40 kg or under (label), once daily. Continuous, long term FDA label
It replaces a missing hormone and is taken every day; the label sets no stopping point.
3.8 to 4.7 hoursFDA label
Measured after single injections in healthy people; peak at about 4 hours. Cleared mainly by the kidneys. Antibodies against the drug can slow its clearance.
Source: Myalept prescribing information section 12.3; Myalepta SmPC 5.2
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized Metreleptin (Myalept) keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 18% charged residues, 44% hydrophobic. Base may help.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- General obesity not caused by congenital leptin deficiency: a listed contraindication
- A previous severe allergic reaction to metreleptin
- HIV-related lipodystrophy, or diabetes or high triglycerides without generalised lipodystrophy: not indicated
- Acquired generalised lipodystrophy or significant blood disorders: weigh carefully, because of the lymphoma cases
- Newborns and infants: mix only with preservative-free water, because the benzyl alcohol preservative can be toxic at that age
Stop and get help
- Swelling of the face or throat, hives or trouble breathing
- Shaking, sweating, confusion or fainting: low blood sugar, especially on insulin, whose dose may need large cuts
- Severe infections, or blood sugar or triglycerides suddenly out of control: possible neutralising antibodies; ask for an antibody test
Common effects
- Headache, low blood sugar and weight loss each in 13% of 48 people in the NIH study (there was no placebo group)
- Abdominal pain in 10%; joint pain, dizziness, ear infection, tiredness, nausea, ovarian cysts and upper respiratory infection in 8% each
- Antibodies against the drug in 84% of those tested, neutralising in 6%
- Pancreatitis in 4%, both in people with past pancreatitis
- Three T-cell lymphomas in the lipodystrophy programme, all in acquired generalised lipodystrophy; a causal link is not established
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Metreleptin (Myalept) approved?
And where the numbers on this page come from.Yes. Metreleptin (Myalept) is FDA approved and available on prescription in the United States. It is also approved in Japan, the European Union, and Canada.
- Approval statusFDA-approved
- RouteUnder the skin (subcutaneous)
- Checked14 October 2026
- Approved outside the USJapan, European Union, Canada: Japan 25 March 2013 (first worldwide), EU 30 July 2018 under exceptional circumstances and Canada 17 January 2024; all three cover some partial lipodystrophy, unlike the US. Also approved in the US.This does not change the United States position above.
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesMyalept prescribing information (3/2024), DailyMedDrugs@FDA, BLA 125390FDA GSRS substance record, metreleptin (UNII TL60C27RLH)Myalepta EU summary of product characteristicsBrown RJ et al., Endocrine 2018;60:479-489Oral EA et al., New England Journal of Medicine 2002;346:570-578Heymsfield SB et al., JAMA 1999;282:1568-1575Ravussin E et al., Obesity 2009;17:1736-1743Amylin and Takeda end pramlintide/metreleptin (Aug 2011)Considine RV et al., New England Journal of Medicine 1996;334:292-295Shionogi, approval in Japan (25 Mar 2013)Pharmaceutical Technology, FDA panel vote (Dec 2013)Health Canada, regulatory decision summary for MyaleptaHCPLive, METRE-PL baseline data (Jun 2026)Chiesi completes acquisition of Amryt (Apr 2023)Welt CK et al., New England Journal of Medicine 2004;351:987-997ClinicalTrials.gov, METRAN (NCT06305182)
What has happened recently
Japan approved it first, on 25 March 2013, for lipodystrophy. The FDA approved Myalept on 24 February 2014 (BLA 125390, orphan drug) for generalised lipodystrophy only, after an advisory committee voted 11 to 1 for that use and 2 to 10 against partial lipodystrophy; it carries a boxed warning and is available only through the MYALEPT REMS. The EU authorised Myalepta on 30 July 2018 under exceptional circumstances, covering generalised lipodystrophy from age 2 and partial lipodystrophy from age 12 when standard treatment fails, and Health Canada approved it on 17 January 2024. No US filing for partial lipodystrophy has been announced; the phase 3 METRE-PL trial is due to finish in October 2026. Chiesi has held it since buying Amryt in April 2023. No biosimilar exists.
You can compare this against the whole library, or read how to check a seller.
What else is like Metreleptin (Myalept)?
Others in Weight loss and metabolic, side by side.If you're weighing Metreleptin (Myalept), it's worth reading Semaglutide, Tirzepatide, and Retatrutide in the same class.
A recombinant copy of human leptin, injected daily to stand in for the hormone missing in lipodystrophy. Not a weight-loss drug.
- Dose
- 2.5 to 10 mg daily over 40 kg; 0.06 to 0.13 mg/kg at 40 kg or under (label)
- How often
- Once daily
The drug in Ozempic and Wegovy: a weekly shot that curbs hunger for steady weight loss.
- Dose
- 0.25 up to 2.4 mg per week (start low, increase slowly)
- How often
- Weekly
The drug in Mounjaro and Zepbound: a weekly shot for major weight loss and blood sugar.
- Dose
- 2.5 up to 15 mg per week (start low, increase slowly)
- How often
- Weekly
An experimental weekly shot with some of the biggest weight-loss numbers yet in trials.
- Dose
- 1 up to 12 mg per dose (start low, increase slowly)
- How often
- Weekly
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- Semaglutide vs Tirzepatide vs Retatrutide
One receptor, two, or three. Mechanism, trial weight loss, side effects, and real cost.
Sources
- Myalept prescribing information (3/2024), DailyMed(2024)Generalised lipodystrophy only; boxed warning for neutralising antibodies and lymphoma; HbA1c -2.0 points and triglycerides median -55% at 12 months; half-life 3.8 to 4.7 hours.
- Drugs@FDA, BLA 125390(2026)Approved 24 February 2014 with orphan status; Chiesi now holds it.
- FDA GSRS substance record, metreleptin (UNII TL60C27RLH)(2026)147-residue sequence; CAS 186018-45-1.
- Myalepta EU summary of product characteristics(2023)EU authorisation 30 July 2018 under exceptional circumstances; partial lipodystrophy subgroup HbA1c -0.9 points and triglycerides -37.4%.
- Brown RJ et al., Endocrine 2018;60:479-489(2018)66 people with generalised lipodystrophy: HbA1c -2.2 points and triglycerides -32.1% at 12 months; 41% of insulin users stopped insulin.
- Oral EA et al., New England Journal of Medicine 2002;346:570-578(2002)9 women over 4 months: HbA1c -1.9 points, triglycerides -60%, liver volume -28%.
- Heymsfield SB et al., JAMA 1999;282:1568-1575(1999)127 obese and lean adults: dose-related but small weight loss, up to 7.1 kg at the top dose in 8 completers over 24 weeks.
- Ravussin E et al., Obesity 2009;17:1736-1743(2009)With pramlintide, weight fell 12.7% against 8.2% on metreleptin alone and 8.4% on pramlintide alone over 24 weeks, measured from enrolment and so including a 4-week pramlintide lead-in.
- Amylin and Takeda end pramlintide/metreleptin (Aug 2011)(2011)Obesity programme stopped after a commercial reassessment, following a previously announced antibody finding.
- Considine RV et al., New England Journal of Medicine 1996;334:292-295(1996)Serum leptin 31.3 ng/mL in obese against 7.5 in normal-weight people.
- Shionogi, approval in Japan (25 Mar 2013)(2013)Approved in Japan on 25 March 2013 for lipodystrophy.
- Pharmaceutical Technology, FDA panel vote (Dec 2013)(2013)11 to 1 for generalised lipodystrophy; 2 to 10 against partial lipodystrophy.
- Health Canada, regulatory decision summary for Myalepta(2024)Decision 17 January 2024: generalised lipodystrophy from age 2; partial from age 12 when standard treatment fails.
- HCPLive, METRE-PL baseline data (Jun 2026)(2026)69-person placebo-controlled phase 3 in partial lipodystrophy; results expected after completion in late 2026.
- Chiesi completes acquisition of Amryt (Apr 2023)(2023)Acquisition of Amryt, the previous holder, completed 12 April 2023; Drugs@FDA and the EMA now list Chiesi.
- Welt CK et al., New England Journal of Medicine 2004;351:987-997(2004)Hypothalamic amenorrhoea: 3 of 8 treated women ovulated.
- ClinicalTrials.gov, METRAN (NCT06305182)(2026)Phase 2 in anorexia nervosa, 50 people planned, recruiting.
Beyond these, 353 records are indexed. Browse the records