Follistatin is a myostatin inhibitor. FLGR242 is a claimed follistatin construct, identity unverified.
| Comparison | Follistatin (FST-344) FST-344 · Follistatin | FLGR242 Follistatin FLGR242 |
|---|---|---|
| How it works | How it works Follistatin blocks myostatin, the signal that limits how much muscle you can build. Animals lacking myostatin are visibly, dramatically muscular. | How it works The idea behind FLGR242 is straightforward. Whether the vial contains it is the open question. |
| What it is | An experimental muscle-builder that releases the body's brake on growth. | Sold as an upgraded follistatin. Nobody outside the sellers has said what is in the vial. |
| Status | Research only | Research only |
| Typical dose | — | — |
| How often | Cycled | No established schedule |
| Stays active | Nothing published | No published figure for this construct |
| Dose comes from | No established range | No established range |
| Cycled? | Commonly cycled Community practice | No established schedule No established range |
| What it does | ||
| Drug class | Myostatin inhibitor | Claimed follistatin construct, identity unverified |
| Used for | Blocks the natural brake on muscle growth so muscles can get bigger. It is very strong in animals; human use is experimental and expensive. | A vendor-introduced follistatin product sold for muscle growth. Its composition rests on seller copy alone. |
| Receptors hit | — | — |
| Numbers | ||
| Full dose line | Research only | No established dose |
| Why that cycle | Cycled by convention rather than to a tested schedule. No published study establishes a block length or a break length for this one. | Nothing has been studied, so nothing can be recommended. Schedules quoted for it are borrowed from follistatin. |
| Weight / effect | Not measured in a trial | Not measured in a trial |
| Chain length | Not disclosed | Not disclosed |
| Common vial | 1 mg | 10 mg |
| Before you start | ||
| Route | Under the skin (subcutaneous) | Under the skin (subcutaneous) |
| Do not use if | Any history of cancer, given the growth-promoting mechanism Pregnancy No established human safety profile | Any active cancer, since myostatin and activin signalling interact with tumour biology Existing heart disease, because myostatin is expressed in cardiac muscle Pregnancy and breastfeeding Banned in drug-tested sport |
What separates them
Proof behind the dose. Every dose here comes from community practice. Not one is backed by a published human study, which is worth knowing before you read the numbers as if they were equivalent.
What doesn't differ: They are both taken the same way (under the skin) and aimed at the same thing (muscle growth). Neither has a measured effect size from a published trial, so there is no number to rank them on.
What people actually report
Follistatin (FST-344)
- High risk: long-term safety is unknown, with a theoretical risk of unwanted tissue or organ growth.
- New lumps or masses
- Any severe or unexpected symptom
FLGR242
- No independent certificate of analysis names what is in the vial. Every composition claim traces to seller copy.
- Sellers contradict each other on the most basic point: some describe a recombinant glycoprotein of roughly 40 kDa, one describes a synthetic peptide analogue. Those are different products.
- Myostatin inhibition has never been shown safe in healthy people, and blocking it affects heart and tendon tissue as well as skeletal muscle.
- Banned in drug-tested sport as a myostatin inhibitor.
- Shortness of breath, chest pain, or swelling in the legs
- Tendon pain, or a joint giving way, since muscle can outgrow the tendon that carries it
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.