FLGR-242 dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
FLGR-242 is a lab-made piece of follistatin, sold on the gray market since late 2025. It is pitched as a way to trap myostatin and build muscle. There are no published studies, no data on how long it lasts in the body, and no safety data on this molecule.
Evidence grade for FLGR-242: 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
3 effects reported, 2 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.
FLGR-242 is a lab-made piece of follistatin sold online as a muscle builder. The idea is that it traps myostatin, the body's brake on muscle. Nobody has published a single study on this molecule. It showed up on the gray market in late 2025.
What people take it for
- Building muscle fast.
- Keeping muscle after a cycle ends, as sellers promise.
What studies in people showed
There are no studies of FLGR-242 in animals or people. The science it leans on is somewhere else. Mice without myostatin grow far more muscle. A gene therapy form of follistatin was tried in six people with muscular dystrophy, and some walked a little further. A 2017 rebuttal said the benefits claimed for that gene therapy were not backed up. None of that was this product.
What people report
Reports, not study results
The good
- Sellers and one influencer promise half a pound to a pound of muscle a week. Those are sales claims, not user reports we could check.
The bad
- Follistatin also blocks activin, which helps control a fertility hormone. Harm to fertility is a possible worry nobody has checked.
- There is no safety data of any kind on this molecule.
Where these come from: The promises come from sellers and the influencer named on this page. The science is the mouse study, the six-person gene therapy study and the rebuttal on this page. We have no real user reports.
My bottom line
This is a gray market protein with zero published data, sold at up to thousands of dollars a vial. I would not inject it. Train hard, eat enough protein and get your blood work done first.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Nothing indexed yet
The 3 citations 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 FLGR-242?
FLGR-242 is a lab-made piece of follistatin, sold on the gray market since late 2025. It is pitched as a way to trap myostatin and build muscle. There are no published studies, no data on how long it lasts in the body, and no safety data on this molecule.
FLGR-242 is sold as a shortened follistatin protein with a claimed add-on that sticks to albumin, a blood protein. Prices run from a few hundred to several thousand dollars a vial. Sellers, and the influencer who made it popular in November 2025, promise half a pound to a pound of muscle a week, with most of it kept after stopping. The idea behind it is real. Follistatin grabs myostatin and activins, and blocking myostatin builds muscle in animals and in one gene therapy trial. But no paper describes FLGR-242. No study measures how long it lasts or what it does. And a 2017 rebuttal challenged the claims made for follistatin gene therapy. Follistatin also grabs activin, which helps control a fertility hormone called FSH. So harm to fertility is a possible worry, and nobody has checked for it.
How does FLGR-242 work?
Like follistatin, it is meant to grab myostatin and activins before they reach their receptors on muscle. That takes the brake off muscle building.
The evidence, in charts
Fig. 1a · how many people
6people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Molecular Therapy 2015 | 6 | 100% |
The whole total is one study of 6. 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
1 of 3 sources here is a study in people. The rest are not.
- Study in people · done in people133%
- Animal study · done in animals133%
- Review of studies · sums up other studies133%
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 3 different years, 1997 to 2017, counted from the list of sources on this page. The newest source on file is from 2017, more than five years ago. Research on it may have gone quiet.
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
- Not disclosed
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Unknown (no published pharmacokinetics)
No amino acid sequence is on file for FLGR-242, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2015A phase 1/2a follistatin gene therapy trial for Becker muscular dystrophy
A gene therapy form of follistatin was tried in six people with muscular dystrophy, and some of them walked a little further. That is the whole human record being pointed at here. It was gene therapy given by doctors in a trial, not the product sold under this name. Six people cannot settle anything.
Six patients; some distance-walked improvement; unrelated to FLGR-242.
- Review of studies2017Unfounded Claims of Improved Functional Outcomes Attributed to Follistatin Gene Therapy in Inclusion Body Myositis
A formal rebuttal. It says the reported benefits of follistatin gene therapy in a muscle disease were not backed up by the data.
Formal rebuttal of the reported efficacy.
- Animal study1997Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member (myostatin)
In mice. Mice without myostatin grew far more muscle. This is the idea behind the product, not evidence for it.
Myostatin loss produces dramatic muscle growth in mice; the basis of the idea, not evidence for the product.
Where to buy FLGR-242
2 sellers list FLGR-242 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 FLGR-242.
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 FLGR-242 | Seller link |
|---|---|---|---|---|---|
| Molecular Edge Peptides | 49 WeakSource-backed 3 of 4. Archive evidence 2 of 4.A | 10 mg | $90.0 | None found for FLGR-242 | View |
| Warrior Makers | 42 WeakSource-backed 2 of 4. Archive evidence 2 of 4.B | 5 mg | $39.8 | None found for FLGR-242 | 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 FLGR-242 · 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 FLGR-242 been tested in people?
Not in a completed trial cited here. 1 human study where nobody was given it. FLGR-242 is a lab-made piece of follistatin, sold on the gray market since late 2025. It is pitched as a way to trap myostatin and build muscle. There are no published studies, no data on how long it lasts in the body, and no safety data on this molecule.
What is the FLGR-242 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 FLGR-242 FDA-approved?
Not approved; nobody has asked the FDA to test it in people (no IND); sold as a research chemical
Does FLGR-242 build muscle?
Nobody knows. There is no published study of FLGR-242 in animals or people. The before and after photos online are marketing, not data.
Is it safe?
Nobody knows. Follistatin also blocks activin, which helps control FSH and fertility, and there is no safety data of any kind. Treat it as high risk.
Is FLGR-242 the same as RTR242?
No. RTR242 is a pill from Retro Biosciences meant to boost the cell's clean-up system, and it is in a regulated early human trial. The names look alike. The two have nothing to do with each other.
Latest reading on FLGR-242
Blog posts about FLGR-242, newest first.