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AnabolicPreliminary grade

Follistatin 344

A myostatin-inhibiting protein with real anabolic mechanism — but zero trials on the retail vial form and the hardest-to-verify sourcing in the catalog.

Verdict — F · Avoid / High-Risk

A real anabolic mechanism wrapped around near-zero human evidence for the product actually sold, the hardest-to-verify sourcing in the catalog, and a genuine off-target risk from systemic myostatin inhibition. Avoid for almost everyone.

Overview

Follistatin-344 is a recombinant form of the natural myostatin-binding protein follistatin, marketed as an injectable for muscle growth. The human follistatin research that exists comes almost entirely from gene-therapy contexts, not from the retail injectable peptide — there are effectively no clinical trials on the vialed product being sold. As a comparatively large, fragile protein it is exactly the kind of molecule independent labs struggle to confirm, so sourcing is the least verifiable in the catalog, and uncontrolled systemic myostatin inhibition carries real off-target tissue-growth and fibrosis concerns.

PepScore Breakdown — the four axes

Evidence

35% weight
17/100

How strong is the published human science?

Human data depth4/40
Regulatory & registry status2/30
Reproducibility & consistency5/20
Mechanism characterized in humans6/10

Sourcing & COA

30% weightOur moat
32/100

Can a buyer obtain an independently-verified, high-purity version? — our proprietary layer.

Independent 3rd-party testing10/35
Verified purity %9/30
COA transparency & batch traceability7/20
Multi-vendor verified availability6/15

Safety & Risk

25% weight
38/100

What is the real-world harm potential?

Documented AEs / toxicity12/40
Contraindication breadth10/25
Regulatory warnings9/20
Therapeutic index / margin7/15

Practicality

10% weight
40/100

How easy is it to actually run a verified version?

Verified-source availability12/35
Cost / value per cycle10/25
Reconstitution & administration12/25
Storage & stability6/15

Sources & Citations

Every claim cites a primary source. Citations are machine-audited against NCBI — see methodology.

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PepScore29/100 · F
Last gradedJune 28, 2026
Next re-grade triggerA controlled human trial of the injectable form plus reliable independent purity verification would be required to move this off Avoid.

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Educational only — not medical advice. PepScore is an educational research grade, not a prescription or dosing recommendation. Some vendor links are affiliate links — this never affects grades. Consult a licensed healthcare provider before using any compound.