Leptin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
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
Evidence grade for Leptin: Moderate. The rule: at least one finished study in people, and at least 100 people who took it. The sum on this page: 6 completed trials, 844 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 844
- Human studies
- 6
- Found nothing
- 0
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
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.
5 effects reported, 3 unwanted, 2 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism, Ageing and longevity, Hormones and growth hormone, Immune system and inflammation
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Leptin is a hormone your fat makes. It tells your brain how much fuel you have stored. When it drops, your body fights to keep weight on. A lab-made version, metreleptin, is approved for a rare disease where the body has almost no fat.
What people take it for
- Losing weight.
- Beating the hunger that comes back after a diet.
- Fixing what people call leptin resistance.
What studies in people showed
For ordinary obesity, it failed. In 1999, 127 adults got leptin shots or a dummy shot. Weight loss was small and all over the place, from 0.7 kg to 7.1 kg lost by dose at 24 weeks. That was in groups of 6 to 8 people who were also dieting. In later studies, 96 to 100 percent of 579 people with obesity made antibodies against it. For people with almost no leptin, it changes lives. In 9 women who had lost their body fat, blood fats fell 60 percent. In the 8 with diabetes, long-term blood sugar fell 1.9 points. Three children born without leptin got it for up to 4 years. Their hunger, weight and puberty all came right.
What people report
Reports, not study results
The good
- In the rare people who lack it, hunger, blood sugar and blood fats get much better.
- Children born without it went through puberty at the right age once treated.
The bad
- Almost everyone treated makes antibodies against it. A few make ones that block their own leptin, and two had a dangerous blood infection.
- Soreness where the shot went in was the main complaint in the obesity study.
- The label warns of a blood cancer called T-cell lymphoma in one form of the rare disease.
Where these come from: No user reports. These come from the obesity study in 127 adults, the lipodystrophy studies, the antibody study and the FDA label on this page.
My bottom line
If you carry extra fat, you already have plenty of leptin. More will not fix it. Build muscle, eat protein, sleep, and get your blood work done.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Leptin has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Losing weight127 people · 1 study
- Blood sugar and insulin32 people · 2 studies
- Feeling less hungry3 people · 1 study
- Losing fat specifically3 people · 1 study
- Immune function3 people · 1 study
- Thyroid3 people · 1 study
29 of the 36 indexed goals have no study of any kind behind Leptin
No study in people, animals or cells on this page reports a result for these. That does not prove Leptin does nothing for them. It does mean anything you have heard about Leptin and one of these did not come from a study cited here.
Show full evidence
What is Leptin?
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. It acts on the part of the brain that runs hunger. Think of it as a starvation alarm, not a fullness signal. When leptin falls, the body fights hard to hold its weight. But adding leptin to someone who already has plenty does very little. The gene was found in mice in 1994. The first people born without leptin were described in 1997. They were two very obese children from one closely related family.
In ordinary obesity, the answer came early. A 1997 to 1998 study gave daily leptin shots to 54 lean and 73 obese adults. Doses ran from a dummy shot up to 0.3 mg/kg. More leptin did mean more weight loss. At 4 weeks, the average ranged from 0.4 kg lost on the dummy shot to 1.9 kg lost at 0.1 mg/kg. The obese group kept going to 24 weeks while eating 500 fewer calories a day. Their weight loss ranged from 0.7 kg (6 people) at the lowest dose to 7.1 kg (8 people) at the highest. At the top dose, results swung widely, give or take 8.5 kg. Soreness where the shot went in was the main side effect. People's starting leptin did not predict who lost weight. That small, patchy effect in people who already had lots of leptin is what leptin resistance means. It is why leptin is not an obesity drug. In later studies, 96 to 100 percent of 579 people with obesity on metreleptin made antibodies against it.
In lipodystrophy, the body has lost most of its fat, so it has almost no leptin. An NIH study gave leptin to 9 women for 4 months, and everyone knew they were getting it. In the 8 with diabetes, their long-term blood sugar number (HbA1c) fell by 1.9 points. Blood fats fell 60 percent and liver size fell 28 percent. A 103 patient US government study and a 25 patient Texas study built on that. On that evidence, the FDA approved metreleptin (Myalept) on 24 February 2014. It is for problems caused by low leptin in people with inherited or acquired generalised lipodystrophy, used on top of diet. The label carries the FDA's strongest warning, a boxed warning, for two risks. Some people make antibodies that block the drug. There is also a risk of a blood cancer called T-cell lymphoma. The drug is only given out through a special safety program. The label says it is not for obesity, partial lipodystrophy, HIV lipodystrophy or liver disease.
In people born unable to make leptin, getting it back changes everything. Three such children got daily leptin shots for up to 4 years. Their appetite, body fat, insulin and blood fats all fell and stayed down. Thyroid hormones went back to normal. Puberty came at the right age. Their immune cells recovered.
Metreleptin is approved in the EU as Myalepta (30 July 2018). It has been sold in Canada under the same name since 2024. Natural leptin is not sold as a product anywhere.
How does Leptin work?
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. It turns down the cells that drive hunger, called NPY and AgRP cells. It turns up the cells that make you feel full, called POMC cells. People with no leptin are always hungry and get very obese very young. They also do not go through puberty normally, have thyroid changes and have weak immune cells. All of that reverses when leptin is given back. In lipodystrophy, leptin lowers blood sugar, blood fats and liver fat. It also cuts how much people eat and how many calories they burn at rest. In ordinary obesity, leptin in the blood is already high. Adding more has only a small effect, and a bigger dose gives a bit more. That is called leptin resistance. How it works has mostly been studied in rats and mice. The ideas include less leptin getting into the brain, weaker signalling and a brake protein called SOCS3. Metreleptin is lab-made human leptin, grown in E. coli bacteria. It is 147 building blocks long. Natural leptin is 146. The extra one is a methionine added at the front. The kidneys clear it from the body. Antibodies against the drug are expected to slow that down.
What have studies in people found about Leptin?
There is a lot of human evidence, but it splits by who was studied. Some people were born without leptin, a handful of children worldwide. Others have generalised lipodystrophy, studied in groups of 9 to 103 patients with no comparison group. In both, giving leptin back reverses the disease, and it is approved. In ordinary obesity, a 127 person study found small, patchy weight loss that grew with the dose. Nearly everyone treated made antibodies against the drug.
- Antibodies (Clin Endocrinol 2016): 96 to 100 percent of 579 people with obesity and 86 to 92 percent of 134 with lipodystrophy made antibodies against metreleptin. In 3 and 4 people, the antibodies also blocked leptin. In the lipodystrophy group, that meant worse blood sugar control and two cases of sepsis, a dangerous blood infection.
- Ordinary obesity (JAMA 1999): 127 adults, some on a dummy shot. At 24 weeks, weight change in obese people ranged from 0.7 kg lost to 7.1 kg lost by dose, give or take 8.5 kg at the top dose. There were only 6 to 8 people per dose group. No leptin obesity drug followed.
- Lipodystrophy studies in the registry: a US government study of 103 patients from 2001 to 2015, and a Texas study of 25 patients, both with results posted. They were the basis of the 2014 approval.
- Partial lipodystrophy (2016): 23 patients for 1 year. HbA1c fell 0.88 points and blood fats fell 120 mg/dL. Both changes were small enough to be chance. The drug is not approved for this.
- Lipodystrophy (NEJM 2002): 9 women for 4 months. HbA1c fell 1.9 points in the 8 with diabetes. Blood fats fell 60 percent and liver size 28 percent. Everyone knew they were getting the drug. NIH ran it.
- Born without leptin (JCI 2002, and NEJM 1999 for the first child): 3 children treated for up to 4 years. Appetite, body fat, insulin, blood fats, thyroid, puberty and immune cells all came right. A fourth child in Canada, treated for 4 years (JCEM 2004), showed the same.
What this does not tell you: The approval rests on studies in a rare disease with no comparison group. Giving dummy shots to people with generalised lipodystrophy was judged unfair and not practical. The effects were big, but nothing was compared against them. The obesity study had only 6 to 8 obese people in each dose group at 24 weeks. At the top dose, results varied more than the average itself. Those people were also on a diet 500 calories a day short. Nothing shows leptin helps ordinary weight loss. Nothing shows it stops weight coming back after a diet in the general public. Nothing shows it is safe for uses off the label. Nearly everyone treated makes antibodies, and a few make ones that block leptin, with serious results. Metreleptin studies say nothing about natural leptin at normal levels in healthy people, because nobody has studied that.
The state of the research
Leptin shows why a hormone that fixes a shortage does not treat the common disease. The 1994 gene paper set off a rush of business interest. Amgen licensed the gene and ran the 1999 obesity study, and that study settled the question. Weight loss was real and grew with the dose. But it was small and swung widely, even at doses up to 30 times the lowest. These were people whose own leptin was already high. Their starting leptin did not predict who lost weight. That result is leptin resistance in one sentence, and it ended leptin as an obesity drug. The antibody data explain the rest. Nearly every treated person made antibodies, and a few made ones that block leptin.
The same molecule then moved to people who lack leptin. Being born without leptin was described in 1997 in two children. It responds to replacement so completely that a few case reports were enough. In generalised lipodystrophy, the body has almost no fat, so it has almost no leptin. That brings severe insulin resistance, very high blood fats and fatty liver. It responded in the 2002 NIH study and in the 103 patient US government program that ran from 2001 to 2015. The drug passed from Amylin Pharmaceuticals, to Bristol-Myers Squibb and AstraZeneca, to Aegerion, then to Chiesi. It won FDA approval in 2014, EU approval in 2018 and a Canadian launch in 2024. The boxed warning reflects what the studies found. There are antibodies that can block the patient's own leptin. There is also T-cell lymphoma in acquired generalised lipodystrophy. That cancer shows up in the disease with or without treatment, but the label tells doctors to weigh it. The label also says the drug has not been shown safe and effective for partial lipodystrophy or for liver disease, including NASH. Both were studied, and neither cleared the bar. Metreleptin is a real success in a rare disease and a proven failure in the common one. Pages that sell leptin as a weight loss hormone are describing the biology of a special strain of mouse, not the study in 127 adults.
The evidence, in charts
Fig. 1a · how many people
846people, across 7 studies in people cited here
| Study | People | Share |
|---|---|---|
| Clinical Endocrinology 2016 | 579 | 68% |
| JAMA 1999 | 127 | 15% |
| NCT00896298, ClinicalTrials.gov 2001 | 103 | 12% |
| Journal of Diabetes and Metabolism 2016 | 23 | 3% |
| New England Journal of Medicine 2002 | 9 | 1% |
| Journal of Clinical Investigation 2002 | 3 | 0% |
| and 1 more cited study in people with a stated count | ||
One study holds 68% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
7 of 10 sources here are studies in people. The rest are not.
- Study in people · done in people770%
- Animal study · done in animals110%
- Review of studies · sums up other studies220%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 8 different years, 1994 to 2018, counted from the list of sources on this page. The newest source on file is from 2018, more than five years ago. Research on it may have gone quiet.
Fig. 3 · legal status at a glance
US
Approved
UK
Prescription
AU
Prescription
CA
Approved
Approved in 2 of 4, by prescription in 2, not approved in 0. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 5 · what the molecule is
- Kind of compound
- Biologic
- Molecule weight
- About 16.15 kDa (metreleptin, 147 residues, FDA label); native mature leptin is 146 residues, UniProt P41159, from an 18,641 Da 167-residue precursor
- Half-life
- About 4.3 hoursShort, 1 to 6 hours
- Chain length
- None on file
No amino acid sequence is on file for Leptin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people1997Congenital leptin deficiency is associated with severe early-onset obesity in humans
This is the case that proved leptin controls hunger in people. Two severely obese children from one closely related family had almost no leptin in their blood despite carrying a great deal of body fat. Both had inherited a fault in the leptin gene from each parent. It was the first hard evidence in humans that this hormone regulates energy balance. Two children is not a population. What it establishes is the biology, not a treatment for anybody else.
Two severely obese children from one highly consanguineous family had very low serum leptin despite high fat mass and a homozygous frameshift deletion in codon 133 of the leptin gene, the first genetic evidence that leptin regulates energy balance in humans.
- Study in people2002Beneficial effects of leptin on obesity, T cell hyporesponsiveness, and neuroendocrine/metabolic dysfunction of human congenital leptin deficiency
Give leptin to the rare children who have none and it transforms them. Three children born unable to make leptin were injected daily for up to four years. Appetite fell, fat mass fell, insulin and blood fats came back towards normal, and puberty arrived at the right age. Immune cells that had been depleted recovered too. This is replacing a missing hormone in people who lack it. It says nothing about giving leptin to people who have plenty. Public money paid for the work.
Three children with congenital leptin deficiency treated with daily subcutaneous recombinant human leptin for up to 4 years: sustained reductions in appetite, fat mass, hyperinsulinaemia and hyperlipidaemia, rapid rise in thyroid hormones, appropriately timed puberty, and reversal of reduced CD4 T cell numbers and impaired T cell function. Non-US government funded.
- Study in people1999Recombinant leptin for weight loss in obese and lean adults: a randomized, controlled, dose-escalation trial
Leptin given to ordinary obese adults produced very little weight loss. 127 people, 54 lean and 73 obese, got one of four doses or a dummy shot. The obese group kept going for 24 weeks while eating less. More leptin did mean more weight loss, but the amounts were small and scattered: about 0.4 kilograms lost on the dummy in four weeks against 1.9 at the best dose. Soreness where the shot went in was the usual complaint. Industry and public money paid for it.
127 adults (54 lean, 73 obese), randomised double-blind placebo-controlled, daily recombinant methionyl human leptin at 0, 0.01, 0.03, 0.1 or 0.3 mg/kg, 4 weeks for all and 24 weeks for obese participants on a 500 kcal/day deficit. Dose-dependent weight loss (p 0.02 at 4 weeks, p 0.01 at 24 weeks): 4-week change -0.4 kg on placebo to -1.9 kg at 0.1 mg/kg; 24-week change -0.7 kg (n 6) to -7.1 kg, SD 8.5 (n 8). Injection site reactions most common. Baseline leptin did not predict response. Industry and US government funded.
- Study in people2002Leptin-replacement therapy for lipodystrophy
Leptin worked, and it worked in the disease it is now approved for. Nine women with lipodystrophy, a condition where body fat is lost from the places it belongs, had very low leptin and eight also had diabetes. They injected leptin twice a day for four months. Average blood sugar fell nearly two points, blood fats fell about 60% and liver size fell about 28%. Diabetes drugs were stopped or cut back. Everybody knew who was getting the drug. Public money paid for it.
Open-label, 9 women aged 15 to 42 with lipodystrophy and leptin below 4 ng/mL, 8 with diabetes, recombinant methionyl human leptin twice daily for 4 months. HbA1c fell 1.9 percentage points (95 percent CI 1.1 to 2.7) in those with diabetes; triglycerides fell 60 percent and liver volume 28 percent in all nine; antidiabetic drugs were stopped or greatly reduced. NIH and non-US government funded.
- Study in people2016Immunogenicity associated with metreleptin treatment in patients with obesity or lipodystrophy
Almost everyone who takes metreleptin makes antibodies against it, and in a few people those antibodies did harm. 579 people with obesity and 134 with lipodystrophy were studied, some for over twelve years. Between 86% and 100% developed antibodies to the drug. Seven made antibodies that blocked leptin itself in laboratory tests. Four of those had generalised lipodystrophy, their metabolic control got worse, and two developed sepsis. This is the safety problem sitting underneath an approved drug. Public money paid for it.
579 metreleptin-treated people with obesity (two randomised trials, 20 to 52 weeks) and 134 with lipodystrophy (open-label, up to 12.3 years). Anti-metreleptin antibodies developed in 96 to 100 percent with obesity and 86 to 92 percent with lipodystrophy. Three people with obesity and four with generalised lipodystrophy developed in vitro neutralising activity, the latter with worsened metabolic control and two with sepsis. NIH funded.
- Study in people2016Efficacy and Safety of Metreleptin in Patients with Partial Lipodystrophy: Lessons from an Expanded Access Program
In partial lipodystrophy the drug did not clearly help. 23 patients with the partial form and either diabetes or very high blood fats took metreleptin for a year, with everybody knowing what they were getting. Average blood sugar drifted down by under a point and blood fats came down, but neither change was big enough to separate from chance. Nausea affected 39% and low blood sugar 26%. Partial lipodystrophy is still outside what the drug is approved to treat.
Open-label expanded access, 23 patients with partial lipodystrophy and diabetes or hypertriglyceridaemia, 1 year: mean HbA1c change -0.88 percentage points (SE 0.62), triglycerides -119.8 mg/dL (SE 84.1), numerically but not significantly lower. Nausea 39 percent, hypoglycaemia 26 percent. Partial lipodystrophy remains outside the approved indication.
- Study in people2001Leptin to Treat Lipodystrophy (NIDDK phase 2)
The study that carried this drug to approval was run without a comparison group. A United States government institute enrolled 103 patients and ran from 2001 to 2015, with everybody knowing what they were taking. Results were posted to the registry in August 2016. A second study of 25 patients in Texas finished in 2014 and posted results in 2019. Long and careful, and still nobody went without the drug for comparison.
National Institute of Diabetes and Digestive and Kidney Diseases, phase 2, 103 enrolled, 2001 to 2015, completed, results posted August 2016. The long-running open-label study that underpinned the approval. A separate 25-patient phase 2/3 at UT Southwestern (NCT00896298) completed in 2014 with results posted 2019.
- Review of studies2014MYALEPT (metreleptin) BLA 125390: approval and label
The FDA record. Approved 24 February 2014 as a new drug, sold by prescription. The March 2024 label carries a boxed warning for two risks. Antibodies can block the drug and the body's own leptin, and severe infections and worse blood sugar have been reported. T-cell lymphoma, a blood cancer, has been seen in acquired generalised lipodystrophy. The drug is only given out through a special safety program. After one shot in healthy volunteers, half of it is gone in 3.8 to 4.7 hours.
Original approval 24 February 2014, Type 1 new molecular entity, marketing status Prescription (openFDA, 11 September 2026). Label effective March 2024: boxed warning for anti-metreleptin antibodies with neutralising activity (consequences may include inhibition of endogenous leptin and loss of efficacy; severe infection and worsening metabolic control reported) and for T-cell lymphoma in acquired generalised lipodystrophy; REMS restricted; half-life 3.8 to 4.7 hours after single subcutaneous doses in healthy volunteers.
- Review of studies2018Myalepta (metreleptin): European public assessment report
The EU approval. Granted on 30 July 2018 to Chiesi as a medicine for a rare disease. Still approved on 11 September 2026.
EU marketing authorisation issued 30 July 2018 to Chiesi Farmaceutici, orphan designation, status Authorised on 11 September 2026.
- Animal study1994Positional cloning of the mouse obese gene and its human homologue
This paper found the gene that is broken in a strain of very fat mice. A separate part found the matching gene in humans. That was the discovery of leptin. US government money paid for it.
Identification of the gene mutated in the ob/ob mouse and of its human homologue, the discovery of leptin. US government funded.
Where to buy Leptin
Leptin is an approved medicine. The approved product comes from a pharmacy, with a prescription. The vials below are sold “for research” and are not the approved drug.
1 seller lists Leptin in our latest read. They are ranked by trust score, then by archive rating, then by certificate tier, then by the lowest price per milligram. Archive evidence is counted before source-backed. Each path is out of 4, and the two are not added. A higher price does not raise the score. The letter is the certificate chip. 0 of them have a published certificate that names Leptin.
Some seller links may pay this site when you buy through them. A payment never changes a seller's tier or rank, and no seller has a say in any page.
| Seller | Trust score | Vial sizes | From, per mg | Certificate for Leptin | Seller link |
|---|---|---|---|---|---|
| Behemoth Labz | 49 WeakSource-backed 3 of 4. Archive evidence 1 of 4.B | 2 mg | $66.6 | None found for Leptin | View |
- LC Lab-confirmed: the issuing laboratory echoed this certificate back
- A Current certificate, independent laboratory named, laboratory not yet checked
- B Certificate published, but no laboratory link, older than a year, or the laboratory did not recognise the published lookup
- C No certificate could be read
Every listing and vial size for Leptin · How the trust score is counted
Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything.
Common questions
Has Leptin been tested in people?
Yes. 844 people given it across 6 completed trials cited here, 0 of which found nothing. 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
What is the Leptin dosage?
Approved medicine. No human dose established for unlabelled uses. Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose. 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.
Is Leptin FDA-approved?
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.
Does leptin help with weight loss?
For people born without it, hugely. In ordinary obesity, a 1999 study of 127 people found small, patchy weight loss that grew with the dose. At 24 weeks, the change ranged from 0.7 kg to 7.1 kg lost, give or take 8.5 kg, in groups of 6 to 8 people. They were also eating 500 fewer calories a day. People with obesity already have high leptin and respond poorly to more. That is what leptin resistance means. No leptin product is approved for obesity.
What is metreleptin approved for?
The FDA approved Myalept (metreleptin) on 24 February 2014. It is for problems caused by low leptin in generalised lipodystrophy, a rare disease where the body loses its fat. It is used on top of diet. The label says it is not for obesity, partial lipodystrophy, HIV-related lipodystrophy or liver disease, including NASH. It is approved in the EU (2018) and Canada (2024) as Myalepta.
What is the boxed warning on metreleptin?
Two risks, checked against the current FDA label. First, the body can make antibodies that block the drug. They may also block the patient's own leptin, so the drug stops working. Severe infections and worse blood sugar control have been reported. Second, a blood cancer called T-cell lymphoma. It has been reported in people with acquired generalised lipodystrophy, both treated and untreated. Because of both, the drug is only given out through a special safety program.
How different is metreleptin from natural leptin?
By one building block. Metreleptin is 147 amino acids long, and natural human leptin is 146. The extra one is a methionine at the front, left over from making it in E. coli bacteria. That is why the two lengths look like they do not match when quoted side by side.
Does leptin resistance mean my leptin is broken?
It describes something doctors see. People with obesity have high leptin in their blood and respond weakly to more of it. The proposed reasons are less leptin getting into the brain, weaker signalling and a brake protein called SOCS3. Those have mostly been studied in rats and mice. In people, it is defined by the fact that added leptin does not cause much weight loss. It is not a defect anyone can measure.