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Follistatin

Also known as: FS344, Follistatin 344

Evidence Tier C-Dextreme riskadvancednot approved

Myostatin/activin antagonist — human work is largely via gene therapy, not consumer peptide vials.

Extreme Risk

This substance is in the extreme platform risk category due to growth-factor signaling, mitogenic potential, or complete absence of human safety data. Exercise maximum caution.

Modality Mismatch

The legitimate clinical modality for this substance (e.g., gene therapy, recombinant protein infusion) is fundamentally different from consumer 'peptide vial' products. Consumer peptide versions may not deliver the same biological activity.

Overview

Follistatin antagonizes myostatin and activin signaling, modulating muscle growth pathways. In legitimate clinical exploration, human work includes gene transfer approaches (e.g., AAV1.CMV.huFS344 protocols) — not comparable to consumer 'peptide vial' narratives. The gap between consumer marketing and legitimate clinical modality is large. Systemic muscle-growth modulation carries theoretical off-target risks; treat as extreme risk.

Research Details

Mechanism of Action

Antagonizes myostatin and activin signaling, modulating muscle growth pathways.

Study Dose Range

Gene therapy: vector genome dosing (not comparable to consumer peptide vials).

Administration Routes

subcutaneous

Onset / Timeline

Gene therapy effects measured over months. Consumer peptide timelines are speculative.

Expected Effects

Myostatin inhibition / muscle growth narrative. Legitimate modality is gene therapy, not RUO peptide.

Adverse Effects

Systemic muscle-growth modulation carries theoretical off-target risks; extreme risk.

Contraindications

No consumer-grade data.

Interaction Notes

Unknown; likely interacts with anabolic pathways and endocrine status.

Related Goals
Muscle Growth & Strength
Known Interactions

contraindicated with IGF-1 LR3

Growth-factor cluster; strong clinical-only gating recommended.

contraindicated with PEG-MGF

Growth-factor cluster; insufficient safety basis for consumer routing.

Available From

No vendors currently listed for this peptide.

Frequently Compared

CJC-1295

Long-acting GHRH analogue studied in human trials for sustained GH/IGF-1 elevation.

Tier B

Ipamorelin

Selective GHSR agonist profiled for more targeted GH release with less ACTH/cortisol spillover than earlier secretagogues.

Tier B-C

GHRP-2

GH secretagogue studied in human stimulation tests with documented endocrine spillover effects.

Tier B

GHRP-6

GH secretagogue with phase I PK data in humans. FDA has flagged compounding safety concerns.

Tier B

Information provided for educational and research reference only. Not medical advice. Not for diagnosing, treating, curing, or preventing disease. Products referenced are labeled Research Use Only (RUO) by vendors; not for human or veterinary use.