Metreleptin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Life-changing in people who make almost no leptin, and useless for ordinary obesity. The clearest case on this site of a hormone that only works when you are short of it.
Evidence grade for Metreleptin: Preliminary. The rule: studied in people, but no published study has had people take it. The sum on this page: 1 human study where nobody was given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
1 human study where nobody was given it
4 effects reported, 3 unwanted, 1 wanted, by people using it, not a trial
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.
Metreleptin is a lab-made copy of leptin, the hormone fat cells make to tell your brain how much fat you carry. It is a prescription drug for people with almost no fat tissue, a rare condition called lipodystrophy. It does not work for ordinary weight loss.
What people take it for
- Fixing the blood sugar, blood fat and liver problems of lipodystrophy.
- Weight loss, which it does not deliver in ordinary obesity.
What studies in people showed
In people with generalised lipodystrophy, who have almost no fat and almost no leptin, it eases severe insulin resistance, very high blood fats and fatty liver. The studies are small, because the disease is rare, and everyone in them got the drug. In people with ordinary obesity, leptin did almost nothing. Their leptin was already high. In partial lipodystrophy, a person's own leptin level did not predict who it would help. Mice with no leptin lost a lot of weight on it. That did not carry over to normal obesity.
What people report
Reports, not study results
The good
- In true leptin shortage, blood sugar, blood fats and liver fat get better.
The bad
- The body can make antibodies that block it, so it stops working and things get worse.
- T-cell lymphoma, a blood cancer, has been reported in people with one type of lipodystrophy, on and off the drug.
- Only certain doctors and pharmacies can supply it, because of these risks.
Where these come from: From the drug warnings and studies on this page. We have no user reports.
My bottom line
A hormone works when you are short of it. Most people are not short of leptin. This is a rare disease drug, not a diet drug.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Nothing indexed yet
The 1 citation on this page do not report a result for any of the 36 goals indexed here. Most of what sits here is something else: a listing of a planned study, a study of how the body handles the drug, a safety report or a government record. None of those tests whether it works.
Show full evidence
What is Metreleptin?
Life-changing in people who make almost no leptin, and useless for ordinary obesity. The clearest case on this site of a hormone that only works when you are short of it.
When leptin was found in 1994, a cure for obesity looked close. Here was the hormone that tells the brain how much fat you carry. Obese mice that lacked it lost a lot of weight when given it back. Then it was given to people with ordinary obesity, and it did almost nothing. Their leptin was already high, and their brains had stopped listening to it.
What survived is metreleptin. It is approved not for obesity but for generalised lipodystrophy. People with that condition have almost no fat tissue, so they make almost no leptin. In them, the effect is big. It eases the severe insulin resistance, very high blood fats (triglycerides) and fatty liver that come from having nowhere to store fat.
The page also has a finding that muddies the simple story. In partial lipodystrophy, a person's own leptin level turned out to be a poor guide to whether the drug would help. So even the "replace what is missing" logic is not as clean as it sounds.
How does Metreleptin work?
Metreleptin is a lab-made copy of human leptin, with one extra amino acid (methionine) added. Fat cells release leptin in line with how much fat you carry. It acts on the brain's hunger center (the hypothalamus). It turns down the nerve cells that drive hunger (NPY and AgRP) and turns up the ones that curb it (POMC). It also tells the systems for reproduction, thyroid and immunity that there is enough food. With no leptin, all those signals read as starving, no matter how much energy the body has stored. That is why replacing it does so much. In ordinary obesity, leptin is already high and the brain has stopped responding, so adding more changes little.
What have studies in people found about Metreleptin?
An approved drug for a rare disease. It helps metabolism a lot in people truly short of leptin, does nothing for ordinary obesity, and carries serious immune risks.
- Approved for problems caused by leptin shortage in generalised lipodystrophy. It improves insulin resistance, triglycerides and fatty liver.
- In ordinary obesity, giving leptin did little. That is the founding negative result of the field.
- In partial lipodystrophy, a person's own leptin level was a poor guide to who would respond. So the "replace what is missing" model is incomplete.
- Boxed warning, the FDA's strongest, for antibodies that block the drug. These can make it stop working and make blood sugar and fats worse.
- Boxed warning for T-cell lymphoma, a blood cancer, reported in people with acquired generalised lipodystrophy both on and off the drug.
- Only certain pharmacies and doctors can supply it. That is unusual, and it reflects both risks.
What this does not tell you: The number of patients is very small. The evidence does not come from large trials with a comparison group. It comes from studies in a rare disease where everyone got the drug, which is normal for conditions this uncommon. Nothing here supports leptin or leptin-like drugs for ordinary obesity. That question was asked, and answered no, decades ago. The problem of antibodies blocking the drug is the reason a newer drug, mibavademab, exists.
The state of the research
Leptin is the most useful failure in metabolic medicine, and this page is where the lesson lives. The hormone was real. The mouse result was real. The leap that giving it would treat obesity was wrong, because obesity is not a leptin shortage. It is closer to the opposite.
That pattern comes up again and again on this site. A hormone falls, or is low in some disease, so giving it looks like an obvious fix. The fix works only in the people who truly lack it. Growth hormone, testosterone and thyroid hormone all have versions of the same story. The question to ask of any hormone treatment is not whether the hormone matters. It is whether you are short of it. That is the same rule the supplements section uses for nutrients.
The evidence, in charts
Fig. 1a · how many people
1study in people cited, but none says how many people took part
number of people not stated
We do not draw a total, because none of the studies in people on this page gives one. Read the sources below for what each study measured.
We read the number of people from the source lines on this page. Where a line gives no number, we count nothing for it. We do not guess.
Fig. 1b · evidence mix
All 1 source here is a study in people.
- Study in people · done in people1100%
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
Every source here was published in 2022.
Too few different years on this page to draw a timeline.
Fig. 3 · legal status at a glance
US
Approved
UK
Approved
AU
Approved
CA
Approved
Approved in all four countries shown. 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
- 16.2 kDa. A 147-amino-acid recombinant protein.
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Roughly three to four hours after subcutaneous injection, which is why it is dosed daily.
No amino acid sequence is on file for Metreleptin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2022Endogenous leptin concentrations poorly predict metreleptin response in patients with partial lipodystrophy
The simple story about how this drug works does not survive its own data. The idea is that people with partial lipodystrophy are short of leptin, so replacing it should help most in those who are shortest. Researchers checked. A person's own leptin level barely predicted whether metreleptin would help them. That is a problem for the replacement story. It means a low leptin reading cannot tell a doctor who will benefit.
The finding that complicates the replacement story. In partial lipodystrophy, a patient's own leptin concentration was a poor predictor of whether they would respond to metreleptin. If replacement were the whole mechanism, baseline deficiency should predict benefit, and it did not.
Common questions
Has Metreleptin been tested in people?
Not in a completed trial cited here. 1 human study where nobody was given it. Life-changing in people who make almost no leptin, and useless for ordinary obesity. The clearest case on this site of a hormone that only works when you are short of it.
What is the Metreleptin dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 1 human study where nobody was given it
Is Metreleptin FDA-approved?
FDA-approved as Myalept for problems caused by too little leptin in generalised lipodystrophy, a rare condition where the body has almost no fat. It carries a boxed warning, the FDA's strongest, for two risks. The body can make antibodies that block the drug, and it can raise the risk of T-cell lymphoma, a blood cancer. It is only supplied through a restricted program. Not approved for obesity or partial lipodystrophy.
Does leptin cause weight loss?
Only in people who are truly short of leptin. That is rare, and mostly means generalised lipodystrophy or being born unable to make leptin. In ordinary obesity, leptin is already high, the brain has stopped listening, and giving more does almost nothing. That result is the foundation of modern obesity drugs.
Why is it restricted?
Two boxed warnings, the FDA's strongest. Patients can make antibodies that block the drug, so it stops working and blood sugar and fats get worse. And T-cell lymphoma, a blood cancer, has been reported in people with acquired generalised lipodystrophy. Both are serious enough that supply is controlled.
How does it relate to mibavademab?
Directly. Mibavademab is an antibody that switches on the leptin receptor whether or not leptin is there. So it can work in patients whose bodies have made antibodies against metreleptin. This site has a page for it, including its finding that it cut weight only in people whose leptin was already low.