Myostatin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Myostatin is the body's brake on muscle growth. Mice bred without it grew two to three times more muscle, which started a whole field. In monkeys, though, a different protein turns out to be the main brake.
Evidence grade for Myostatin: Moderate. The rule: at least one finished study in people, and at least 100 people who took it. The sum on this page: 3 completed trials, 188 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 188
- Human studies
- 3
- Found nothing
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
3 completed trials, 188 people given it
No first-hand reports gathered yet. That is a gap in what we have collected, not a finding that nothing has been reported.
Goal pages: Fat loss and metabolism, Muscle and strength
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.
Myostatin is your body's brake on muscle. Muscle makes it, and it tells muscle to stop growing. Mice without it grow huge. In people and monkeys, a related protein called activin A does most of the braking. That is why blocking myostatin alone has mostly failed.
What people take it for
- Building muscle with supplements sold as myostatin blockers.
- Keeping muscle while losing fat.
- Muscle wasting diseases, through drugs aimed at this pathway.
What studies in people showed
Blocking myostatin alone has not worked in people. In boys with Duchenne muscular dystrophy, an antibody against it did no better than a dummy after 49 weeks. Two other approaches did work. One stops myostatin being switched on. In 188 children and young people with spinal muscular atrophy, it scored about 1.8 points better on a movement scale after a year. The higher dose alone did not beat the dummy. Another drug blocks the receptor that myostatin shares with activin A. In adults with type 2 diabetes and obesity, fat fell 7.5 kg and muscle rose 1.7 kg over 48 weeks. The mouse result from 1997 did not carry over to people.
What people report
Reports, not study results
The good
- Blocking the shared receptor took off fat and added muscle in people with diabetes.
- In spinal muscular atrophy, one drug gave a small gain in movement.
The bad
- The myostatin-only antibody did nothing for boys with muscular dystrophy.
- Adding muscle did not always mean moving better. Older adults gained muscle on the receptor drug without better function.
- No supplement has ever been shown to block myostatin in a person.
Where these come from: All of this comes from the human trials on this page. We have not collected user reports on myostatin blocker supplements for this page.
My bottom line
If big drug company antibodies built for this exact target mostly failed, a supplement will not do it. Lift heavy, eat your protein, and check your blood work. That still beats anything sold as a myostatin blocker.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Myostatin 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.
- Keeping or building muscleno headcount stated · 2 studies · 1 found nothing
- Losing fat specificallyno headcount stated · 1 study
- Blood sugar and insulinno headcount stated · 1 study
33 of the 36 indexed goals have no study of any kind behind Myostatin
No study in people, animals or cells on this page reports a result for these. That does not prove Myostatin does nothing for them. It does mean anything you have heard about Myostatin and one of these did not come from a study cited here.
Show full evidence
What is Myostatin?
Myostatin is the body's brake on muscle growth. Mice bred without it grew two to three times more muscle, which started a whole field. In monkeys, though, a different protein turns out to be the main brake.
Myostatin is made by muscle, and it tells muscle to stop growing. Remove it from a mouse and you get an animal two to three times more muscular. That 1997 result started a drug industry and a lot of supplement marketing.
The human story is messier and more interesting. Antibody drugs that block only myostatin have mostly failed in trials. The best explanation came from a study in monkeys. In primates, a related protein called activin A, not myostatin, does most of the braking on muscle. That is why drugs that block the receptor both proteins share have done better than drugs that block myostatin alone. It is also why anything sold to you as a myostatin blocker deserves hard questions.
How does Myostatin work?
Myostatin travels in the blood in a locked, inactive form. Once unlocked, it docks on a receptor on muscle cells, mainly one called ActRIIB. That sends a signal inside the cell that slows muscle building and keeps muscle repair cells quiet. Activin A uses the same receptor. That is why blocking the receptor and blocking myostatin alone behave so differently.
What have studies in people found about Myostatin?
A lot of human trials, and mostly a record of failure for the obvious approach. Blocking myostatin alone has not worked in people, again and again. Blocking the receptor it shares with activin A has worked. So has stopping myostatin from being unlocked in the first place.
- Apitegromab stops myostatin being unlocked, rather than blocking the finished protein. In 188 children and young people with spinal muscular atrophy who could not walk, all already on standard treatment, it had positive results in a large final-stage trial.
- Bimagrumab blocks the shared receptor, so it stops myostatin and activin A together. Over 48 weeks it caused big changes in body makeup: fat down 20.5% and muscle up 3.6%.
- Domagrozumab, an antibody that blocks only myostatin, was tested in boys with Duchenne muscular dystrophy. On the main test of how they moved, the drug and the dummy came out the same. Nothing else separated, and gains in muscle size did not hold up.
- Landogrozumab, another antibody that blocks only myostatin, was tested in a mid-sized study after hip replacement surgery.
- One case report describes a child born without working myostatin who was extremely muscular.
What this does not tell you: One child is not a safety record. The monkey finding, that activin A matters more than myostatin, means results with myostatin-only drugs may not carry over the way the mouse work suggested. And the most striking body change here, on bimagrumab, came from blocking the receptor, which is not specific to myostatin. Crediting that to myostatin blocking is a mistake. Also, bimagrumab added muscle in older adults with age-related muscle loss without improving how well they could move. Our training pages cover that.
The state of the research
Myostatin is the clearest case on this site of an amazing animal result that did not carry over to people. It shows why you should always check which animal. The 1997 mouse result is truly striking, and it is a mouse. Two decades of human trials of myostatin-only antibodies produced a string of drugs that did not help people move better. In the best known one, the drug and the dummy came out almost exactly the same.
The 2017 monkey study explains it. Read it before any claim about blocking myostatin in people. In primates, the main brake on muscle seems to be activin A. That one finding reshapes the field. It predicts why blocking the shared receptor beat blocking myostatin alone. And it almost never shows up in consumer articles about myostatin.
On supplements sold as myostatin blockers, here is the bar. Drug-grade antibodies built for exactly this target, given straight into the vein, mostly failed to change what patients could do.
The evidence, in charts
Fig. 1a · how many people
188people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| SAPPHIRE, Lancet Neurology 2025 | 188 | 100% |
The whole total is one study of 188. 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. 3 more studies in people give no headcount and are not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
4 of 6 sources here are studies in people. The rest are not.
- Study in people · done in people467%
- Animal study · done in animals233%
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 6 different years, 1997 to 2025, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the 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. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Biologic
- Molecule weight
- Precursor 375 amino acids, 42,750 Da. Mature signalling domain is residues 267 to 375, 109 amino acids, circulating as a dimer (UniProt O14793).
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Circulates as a latent complex; no single agreed circulating half-life is asserted here.
No amino acid sequence is on file for Myostatin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2004Myostatin mutation associated with gross muscle hypertrophy in a child
One child born without working myostatin was extremely muscular. That is the whole report. It gets quoted all the time as proof that blocking myostatin will safely build muscle in adults. It cannot carry that weight. A person born with a gene switched off is not the same as an adult given a drug for a year. One child is one child, and nobody was compared against anyone.
One child, one loss-of-function mutation, extreme muscularity. It is a case report. It is not evidence that blocking myostatin is safe or useful at scale, and it is routinely cited as though it were.
- Study in people2020Randomized phase 2 trial and open-label extension of domagrozumab in Duchenne muscular dystrophy
A drug that blocked myostatin alone failed in boys with Duchenne muscular dystrophy. Boys got the antibody or a dummy. After 49 weeks, the time to climb four stairs differed by a quarter of a second, which is nothing. No other measure of how the boys were doing separated the two groups. Gains in muscle size did not hold up either. This is the clearest evidence that blocking myostatin alone does not turn into better movement.
A pure anti-myostatin antibody against placebo. The difference in four-stair climb time at week 49 was 0.27 seconds, 95% CI minus 7.4 to 7.9, p = 0.94. No secondary clinical endpoint separated and muscle volume gains were not significant.
- Study in people2025Safety and efficacy of apitegromab in nonambulatory type 2 or type 3 spinal muscular atrophy (SAPPHIRE): a phase 3, double-blind, placebo-controlled trial
It helped a little, and the picture was mixed. 188 children and young people with spinal muscular atrophy who could not walk took part at 48 hospitals in nine countries. All were already on nusinersen or risdiplam. After a year, the apitegromab groups together scored about 1.8 points better on a movement scale than the dummy group. The higher dose on its own did not beat the dummy. Side effects looked the same in both. Scholar Rock paid for it.
188 randomised across 48 hospitals in nine countries, 128 to apitegromab and 60 to placebo, all already on nusinersen or risdiplam. In the 2 to 12 year group the least squares mean HFMSE difference at 12 months was 1.8 points over placebo (95% CI 0.30 to 3.32, p=0.019). The 20 mg/kg dose against placebo was 1.4 points and did not reach significance (95% CI -0.34 to 3.13, p=0.11). Adverse event incidence and severity were similar between arms. Apitegromab blocks activation of pro and latent myostatin rather than the mature protein. Scholar Rock funded.
- Study in people2021Effect of bimagrumab vs placebo on body fat mass among adults with type 2 diabetes and obesity: a phase 2 randomized clinical trial
Blocking the receptor, not the hormone, caused big changes in body makeup. Adults with type 2 diabetes and obesity took bimagrumab or a dummy for 48 weeks. Fat fell by about a fifth, 7.5 kg, against almost nothing on the dummy. Muscle rose by 1.7 kg, waists shrank 9 cm, and average blood sugar fell by three quarters of a point. Note what this drug blocks. It shuts the receptor down, so it blocks activin A as well as myostatin.
Receptor-level blockade rather than myostatin-only blockade, so it neutralises activin A too. At 48 weeks fat mass fell 20.5% (7.5 kg) against 0.5% on placebo, lean mass rose 3.6% (1.7 kg), waist fell 9.0 cm and HbA1c fell 0.76 points, all p < 0.006.
- Animal study1997Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member
In mice. Mice bred without myostatin had two to three times more muscle. This is where the whole field started, and it is a mouse result.
Mouse. Myostatin-null mice are two to three times more muscular. The origin of the entire field, and a mouse result.
- Animal study2017Activin A more prominently regulates muscle mass in primates than does GDF8
In monkeys. In primates, a related protein called activin A, not myostatin, seems to be the main brake on muscle. This is the key paper for understanding why drugs that block only myostatin let people down.
Cynomolgus monkey. In primates activin A, not myostatin, appears to be the dominant ligand restraining muscle mass. This is the single most important paper for understanding why pure anti-myostatin drugs underperformed in people.
Where to buy Myostatin
1 seller lists Myostatin 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 Myostatin.
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 Myostatin | Seller link |
|---|---|---|---|---|---|
| Pure Health Peptides | 25 InsufficientSource-backed 1 of 4. Archive evidence 0 of 4.C | 2 mg | $99.5 | None found for Myostatin | 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 Myostatin · 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 Myostatin been tested in people?
Yes. 188 people given it across 3 completed trials cited here, 1 of which found nothing. Myostatin is the body's brake on muscle growth. Mice bred without it grew two to three times more muscle, which started a whole field. In monkeys, though, a different protein turns out to be the main brake.
What is the Myostatin dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 3 completed trials, 188 people given it
Is Myostatin FDA-approved?
Myostatin is a protein the body makes, not a drug. Drugs that target it are investigational. Apitegromab has results from final-stage studies in spinal muscular atrophy.
Do myostatin inhibitor supplements work?
No human trial shows any supplement meaningfully blocks myostatin or builds muscle that way. Keep this in mind. Antibody drugs built for this exact target, given into the vein in proper trials, mostly failed to improve how people moved.
Why did the mouse result not translate?
The best explanation is a monkey study. In primates, activin A, not myostatin, is the main brake on muscle. Block myostatin alone in a primate and activin A is still doing most of the braking.
Has anything in this pathway worked in humans?
Yes, two things, and neither blocks myostatin alone. Apitegromab stops myostatin being unlocked and had positive results in a large final-stage trial in spinal muscular atrophy. Bimagrumab blocks the shared receptor and caused big changes in fat and muscle in type 2 diabetes.
What about the muscular child?
That is one case report from 2004 about a single child whose myostatin gene did not work. It shows the pathway matters in people. It says nothing about whether blocking it in an adult is safe or useful, and it gets quoted as if it does.