Follistatin 344 (Follistatin 344 (FST-344))
A naturally occurring glycoprotein that binds and neutralizes myostatin and activin. The longest isoform enabling significant muscle hypertrophy by removing growth inhibitors.
How it works
Binds myostatin and activin A with high affinity, preventing ActRIIB receptor activation. Removes the brake on muscle growth allowing uninhibited satellite cell proliferation.
Key facts
- Molecular weight: 36,000 Da
- Half-life: 2-4 hours
- Bioavailability: Moderate (SubQ)
- Storage: Lyophilized: -20°C. Reconstituted: 2-8°C for 7 days.
Dosing overview
- Typical dose: 100-200 mcg
- Frequency: Daily for 10-30 days
- Duration: 10-30 day protocols
- Route: Subcutaneous
Reported benefits
- Significant muscle growth
- Myostatin inhibition
- Increased strength
- Activin neutralization
- Enhanced recovery
Possible side effects
- Limited safety data
- Theoretical reproductive effects
- Joint stress from rapid gains
- Cardiac muscle effects (theoretical)
Research
- Follistatin gene therapy for muscle wasting (2022): AAV-delivered FST-344 increased quadriceps volume by 15% in Becker MD patients.
- Myostatin inhibition by follistatin in primates (2020): Increased lean muscle by 20% without significant off-target effects over 8 weeks.
Community reviews of Follistatin 344
- bio_optimal rated it 5/5 - Solid compound with real results: Been using Follistatin 344 for about 3 months and the results are clear. Not overnight dramatic, but a steady, consistent improvement that became undeniable by the end of the first month. The mechanism makes sense based on what I have read in the literature, and my subjective experience matches the expected timeline. Benefits built gradually and plateaued at a good level. Side effects were minimal to none at the dose I used. Followed proper protocols for sourcing, storage, and administration. Would recommend to others who have done their research and have realistic expectations.
- cycle_sage rated it 5/5 - Noticed clear benefits within weeks: Added Follistatin 344 to my protocol about 6 months ago and it has earned its place. The benefits became noticeable around week 2-3 and have been consistent since. What I appreciate about this compound is the predictability. It does what the research suggests it should do, at roughly the timeline you would expect. No surprises, no dramatic swings, just steady improvement. No notable side effects to report at my dose. Sourcing is always the challenge with research compounds, insist on third-party testing. Storage and reconstitution per standard protocols. Plan to continue.
- careful_claire rated it 5/5 - Worth adding to the protocol: Follistatin 344 has been a worthwhile addition. I am data-driven and tracked relevant markers before, during, and after. The improvement is measurable and correlates with the intervention timeline. What sets this apart from some compounds I have tried is the consistency. Benefits did not fluctuate wildly or disappear. They built up and maintained. That gives me confidence in the mechanism. Tolerance has been excellent. Nothing in my bloodwork or subjective experience raised any flags. This is the kind of compound that does its job quietly without causing problems. Exactly what you want.
- liam_sleepnerd rated it 5/5 - 12 Weeks of FST-344 in the Weight Room: I ran Follistatin 344 for about 12 weeks while I was lifting hard after long clinic shifts, and tbh it was the first thing that made my training log look obviously different. For me, the big change was how fast I kept adding load and how full my legs and back looked by the end of the cycle, even with the same food and sleep routine. Could be that I was in a really dialed-in stretch, but the trend was hard to ignore. I’m giving it 5 stars because, in my own experience, it moved the needle in a way most stuff does not.
- hank_v rated it 5/5 - big upside, but my elbows complained a bit: i ran follistatin 344 for about 3 months, mostly because at 43 and sitting in a startup all day in germany, i wanted a push for training without feeling broken. for me it seemed to add noticeable fullness and strength. the downside was some odd tendon and elbow grumbling, which made me respect it a bit more. still, i rate it very highly.
- jared501 rated it 5/5 - Four Weeks That Actually Moved the Needle: I ran Follistatin 344 for about 4 weeks while keeping up with my normal lifting and a pretty busy life here on the West Coast, and for me it fit better than I expected because I could still do my early gym sessions before the day got away from me. I’m a retired firefighter in my late 30s, so I care a lot more about staying strong and recovering well than chasing some bro science fantasy, and this seemed to help me add reps and feel more solid under the bar. Could be partly placebo, sure, but the change felt real enough that I kept logging bigger numbers and better workouts. 5 stars from me.
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Research and educational reference only. Not medical advice.