|All Peptides

Read the full guides

DosingResults

Follistatin-344

Last reviewed: April 18, 2026 by The Peptide Catalog Team

A myostatin inhibitor that unlocks muscle growth beyond genetic limits. Follistatin-344 is a synthetic version of the naturally occurring follistatin protein that inhibits myostatin and activin signaling. By blocking these muscle-growth suppressors, it promotes significant increases in lean muscle mass. Widely researched for muscle-wasting conditions, athletic performance, and body composition.

CategoryGrowth & Repair Peptides
Classmyostatin inhibitor
GoalMuscle Growth
Overview

Core Benefits

Key Advantages
Myostatin inhibition
Blocks myostatin — the body's natural muscle-growth limiter.
Muscle research peptide
Drives hypertrophy and hyperplasia in research models.
Body composition shift
Improves muscle-to-fat ratio over a short cycle.
Satellite cell activation
Unlocks muscle stem cells for repair and growth.
Natural endogenous protein
FS-344 is a synthetic copy of an endogenous isoform.
Safety concerns to weigh
Cycles must be short — long-term safety data is thin.

These are educational summaries of commonly discussed effects in wellness/regenerative contexts, not guarantees.

Follistatin-344 Results Timeline

Progression
1
Week 1–2
Physical Changes
Myostatin suppression begins, satellite cell activation
Performance & Recovery
May notice improved workout recovery
Other Benefits
No noticeable external changes yet
2
Week 3–4
Physical Changes
Early gains in muscle fullness and strength
Performance & Recovery
Improved training capacity, reduced soreness
Other Benefits
Body composition shifts beginning
3
Month 2–3
Physical Changes
Visible lean mass increases, improved definition
Performance & Recovery
Significant strength gains, enhanced recovery
Other Benefits
Fat-to-muscle ratio improving noticeably
4
3+ Months
Physical Changes
Peak hypertrophy effects for cycle
Performance & Recovery
Sustained strength and growth beyond natural limits
Other Benefits
Typical cycle: 10-30 days; consult protocol for cycling

Timeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.

Read the full Follistatin-344 results timeline →

Evidence at a glance

Two parallel grades per outcome — clinical RCT depth and real-world community adoption. See the Research Overview below for citations and detail.

OutcomeClinical EvidenceCommunity Evidence
Becker muscular dystrophy gene therapyWeakWeak
Muscle hypertrophy in nonhuman primatesModerateWeak
Recombinant follistatin-344 peptide for hypertrophyPreliminaryWeak
How It WorksMyostatin Inhibitor — Muscle Growth Peptide

Target → Myostatin Inhibition → Muscle Growth → Outcomes

1
Target

Myostatin & Activin (TGF-β Superfamily Ligands)

Follistatin-344 binds and neutralizes myostatin and activin — two proteins that actively suppress muscle growth. Myostatin acts as a "brake" on muscle development. By blocking the brake, Follistatin-344 allows muscle to grow beyond its normal genetic limit.

2
Cellular Signal

Myostatin/Activin Sequestration → Smad Pathway De-Repression

Follistatin binds myostatin before it can reach ActRIIB receptors on muscle cells. This prevents the Smad 2/3 signaling cascade that normally limits protein synthesis and satellite cell activation. With the brake removed, muscle cells enter an enhanced growth state.

3
Systemic Effect

Increased Muscle Protein Synthesis + Satellite Cell Activation

Without myostatin suppression, muscle fibers undergo both hypertrophy (bigger fibers) and hyperplasia (more fibers). Satellite cells — the muscle stem cells responsible for repair and growth — are activated at higher rates. Effects are seen across all skeletal muscle groups.

4
What You Notice

Lean Mass Gains → Strength → Improved Body Composition

Noticeable increases in lean muscle mass over weeks of use. Strength gains that exceed training alone. Improved body composition with favorable muscle-to-fat ratio changes. Effects are most pronounced when combined with resistance training.

What Makes This Peptide Different

Follistatin-344 is unique in targeting the natural limiter of muscle growthrather than stimulating growth directly. While GH peptides (CJC-1295, Ipamorelin) and IGF-1 LR3 push growth signals harder, Follistatin removes the ceiling. The FS-344 isoform undergoes cleavage to FS-315, which has broader tissue distribution than the FS-288 isoform. Naturally occurring — your body already produces follistatin, just not enough to override myostatin completely.

Research overview

Outcome-by-outcome look at what the evidence actually supports for Follistatin-344, including human vs. animal study counts and our editorial take on each.

Becker muscular dystrophy (gene therapy)

Clinical:WeakCommunity:Weak

Mendell 2015 (Phase 1/2a, n=6) injected AAV1-FS344 into the quadriceps of Becker muscular dystrophy patients and reported some improvement in 6-minute walk distance and muscle fiber diameter. The trial is small, open-label, and uses gene therapy delivery — not exogenous recombinant peptide injection. Community use of synthetic 'follistatin-344 peptide' has no clinical evidence base.

1 human study · 8 animal studies

Key findings & citations
  • Mendell 2015: AAV1-FS344 gene therapy improved 6MWT in some BMD patients.
  • Kota 2009: AAV-FS344 increased muscle mass in nonhuman primates.
  • All clinical work is gene therapy — not exogenous recombinant follistatin-344 peptide.
  • No published human RCT of injected recombinant follistatin-344.

Our take

Gene therapy is not the same as injecting a peptide. Community use of 'follistatin-344' as a peptide injection has no clinical evidence — the published trials don't translate.

What Follistatin-344 doesn't do

Claims that current evidence does not support. Worth knowing before you set expectations.

Follistatin-344 Vendors

COA

Swiss Chems

Score
10/10
Price
$139.99
Amount
1mg
Cost/mg
$139.99/mg
Ships Worldwide
View at Swiss Chems
Dosing ProtocolMuscle Growth / Myostatin Inhibition

Educational reference only. Individual responses vary. Consult healthcare provider before use.

Vial Size
1 mg vial
Reconstitution
2 ml BAC water
Dose
50 mcg (10 units on 1ml syringe)
Timing
AM — 30 minutes pre-workout (intramuscular)
Frequency
Training days only
Duration
8 weeks on, 8 weeks off
Protocol Notes
Inject IM into target muscle group 30 min before training. Binds and neutralizes myostatin (GDF-8). Store reconstituted vials at 2-8°C, use within 14 days.

Why This Dosing Protocol

Why short cycles (10-30 days)?Follistatin-344's potent myostatin suppression should be cycled to prevent potential off-target effects on other TGF-β pathways that follistatin also modulates (FSH suppression, for example).

Why combine with training? Myostatin inhibition removes the growth ceiling, but the growth signal still needs to come from somewhere — mechanical loading from resistance training provides the stimulus that follistatin allows the body to respond to more aggressively.
Full Dosing GuideReconstitution CalculatorCycle Cost Calculator

Reconstitution Calculator

Dilution math and unit conversions. Prefilled using a common vial size for this peptide.

Open calculator

Storage & Handling

Storage at a glance

Proper storage temperatures, shelf life, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.

Powder: Freezer
1+ year at -20°C
Reconstituted: Fridge
4 weeks max at 2-8°C
View Complete Storage Guide

Handling specifics

Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.

Powder storage (very stable)
  • Freezer (-20°C): 1+ year
  • Refrigerator (2-8°C): 1-3 months
  • Room temperature: 2-3 weeks (emergency only)
Reconstituted storage (fragile)
  • MUST refrigerate at 2-8°C
  • 4-week maximum shelf life
  • NEVER freeze after reconstitution
  • Use bacteriostatic water for multi-dose
Molecular Structure
  • Length: 344 amino acids
    (Full-length isoform of follistatin.)
  • Target: Myostatin (GDF-8)
    (Also binds activin A and GDF-11.)
  • Mechanism: Ligand trap
    (Binds and sequesters TGF-β ligands.)
  • Primary Use: Muscle growth
    (Removes genetic limits on hypertrophy.)
Key binding domain
Follistatin Domain 1–3 (FS-I, FS-II, FS-III)
FS-344 contains three follistatin domains that form a "molecular cage" around myostatin, preventing it from binding its receptor (ActRIIB) and suppressing muscle growth.
Key takeaway: Follistatin-344 removes the body's natural brake on muscle growth. Studied in gene therapy trials for muscular dystrophy, it represents one of the most direct approaches to enhancing muscle mass beyond genetic potential.

FAQ

How does Follistatin-344 promote muscle growth?

Follistatin-344 binds and neutralizes myostatin (GDF-8), the protein that limits how much muscle your body can build. By removing this natural brake, FS-344 allows both hypertrophy (bigger muscle fibers) and potentially hyperplasia (more fibers). It also inhibits activin A, which has additional growth-suppressive effects.

What is the difference between Follistatin-344 and Follistatin-315?

FS-344 is the full-length isoform that gets cleaved in the body to produce FS-315 and FS-288. FS-315 is the primary circulating form and the most relevant for muscle effects. FS-288 binds more tightly to cell surfaces and is important in reproductive tissues. Research peptide vendors typically sell FS-344 as it produces both active forms.

How long are Follistatin-344 cycles?

Community protocols typically run 10–30 days due to the peptide's potency. Longer cycles aren't well-studied. Most users report noticeable strength and fullness gains within the first 2 weeks. Cycling off allows the body to re-establish baseline myostatin levels.

Is Follistatin-344 the same as the gene therapy used in muscular dystrophy trials?

Similar concept, different delivery. Gene therapy trials (like those by Mendell et al.) use AAV vectors to make muscles produce follistatin endogenously and permanently. Injectable FS-344 provides temporary exogenous follistatin that clears from the body. The gene therapy approach showed promising safety and efficacy in Becker muscular dystrophy patients.

Can Follistatin-344 be stacked with other peptides?

Some researchers combine FS-344 with growth hormone secretagogues (CJC-1295/Ipamorelin) or IGF-1 LR3 for synergistic muscle-building effects. The rationale is that FS-344 removes the growth ceiling while GH/IGF peptides provide the anabolic stimulus. Each should be injected separately.

How long does reconstituted peptide last?

Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.

Is this peptide legal to purchase?

Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.

New to peptides?

Take our Peptide Match tool to find the best peptide for your goals. You can also read our Complete Guide to Peptides to learn the basics.

Follistatin-344 Research Articles

dosing

Follistatin-344 Dosage: 50mcg Pre-Workout Protocol

Training-day-only dosing at 50mcg IM 30min before lifting. Covers reconstitution from 1mg vials, 8-week cycling, and stacking.

articles

Peptides vs SARMs vs Steroids: Muscle Comparison

Peptides are safer. SARMs are stronger. Steroids are strongest. Legal, safety, cost trade-offs for muscle goals.

articles

Peptides for Strength vs Mass: Which Goal Wins

IGF-1 for site-specific strength. GHRH+GHRP for systemic mass. Picking the right compound for powerlifting vs bodybuilding.

benefits

Follistatin-344: Remove the Brake on Muscle

Myostatin inhibition gets all the attention — but follistatin's strongest clinical data is in a different area entirely. 5 effects ranked by evidence.

Disclosure: we may earn affiliate commission from qualifying purchases. Educational information only — not medical advice.