Peptide Research Index
⚠️ Educational only · Not medical advice · Consult a doctor · Most peptides are research-only / not FDA-approved for human use
⚠️ Educational only · Not medical advice · Consult a doctor · Most peptides are research-only / not FDA-approved for human use
Also: FS-344
Myostatin InhibitorLast Updated: April 1, 2026
Follistatin-344 (also known as FS-344) is a prominently researched experimental compound classified strictly within the Myostatin Inhibitor framework. Operating primarily through advanced pharmacological pathways, it functions by blocks myostatin (the body's muscle growth limiter) and activin, allowing enhanced muscle development and regeneration beyond normal physiological limits. with a documented biological half-life of roughly 6 hours, in preclinical investigative trials and independent academic studies, researchers utilizing Follistatin-344 have documented significant, quantifiable biological outcomes, primarily focusing on muscle hypertrophy, strength. Typical research protocols investigate administering 100 to 100mcg via subq pathways 7x/wk. However, it is critically important to understand that while Follistatin-344 demonstrates profound physiological potential in highly controlled laboratory settings, it remains classified strictly as a research chemical and has not been approved by the United States Food and Drug Administration (FDA) for human therapeutic, diagnostic, or dietary consumption. Independent chemical analysis via rigorous third-party Certificate of Analysis (COA) testing utilizing High-Performance Liquid Chromatography (HPLC) and Mass Spectrometry (MS) remains the industry gold standard for verifying its base elemental stability when reconstituted appropriately in sterile bacteriostatic water.
Blocks myostatin (the body's muscle growth limiter) and activin, allowing enhanced muscle development and regeneration beyond normal physiological limits.
Rodino-Klapac et al. (Mol. Ther.): AAV-delivered follistatin 344 increases muscle mass and fiber diameter across multiple animal species without adverse reproductive or endocrine effects.
preclinicalKalista et al.: Review of follistatin's role as primary endogenous myostatin antagonist and its therapeutic potential for muscular dystrophies and sarcopenia.
preclinicalMendell et al. (Mol. Ther.): Phase I clinical trial of AAV1-follistatin gene transfer in Becker muscular dystrophy patients shows improved 6-minute walk test with no adverse effects.
moderateResearch demonstrating follistatin's broader metabolic role in adipocyte browning, energy expenditure, and metabolic health beyond muscle hypertrophy.
preclinicalResearch-only. Potent effects potential for unregulated growth. Limited human safety data. Phase I gene therapy trials show safety.
⚠️ For educational purposes only. Not medical advice. Consult a healthcare professional before using any peptide.
Very short cycles. 100mcg/day common. Acts via myostatin/activin inhibition effects compound over days.
Last updated: 2026-01 · Laws change frequently. Verify current status in your jurisdiction.
Weeks 2-4
Initial myostatin inhibition; muscle fullness and pumps
Month 2-3
Measurable lean mass increase; strength gains
Long-term
Very limited long-term human data; Phase I gene therapy shows safety
| Side Effect | Incidence | Severity |
|---|---|---|
Limited human safety data | Investigational only | mild |
Injection site reaction | ~5% of users | mild |
Theoretical cancer promotion Myostatin inhibition could allow unregulated cell growth | Mechanism-based concern | rare |
Incidence rates sourced from published clinical trial data where available; otherwise based on community research observations.
Finding verified, high-purity Follistatin-344 requires rigorous COA verification. We independently evaluate vendors based on third-party HPLC testing, purity thresholds (≥98%), and batch-specific documentation.
View COA-Verified Follistatin-344✓ Third-party tested·✓ US shipping·✓ COA on every batch
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PeptiDex. (2026). Follistatin-344. PeptiDex Research Platform. https://peptidex.app/library/follistatin-344
12 stacks • exact dosages • cycle lengths • printable reference
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