Side-by-side · Research reference

Follistatin-344vsMT-1

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

AHuman-MechanisticHUMAN-REVIEWED4/58 cited

BFDA-ApprovedHUMAN-REVIEWED9/51 cited

Follistatin-344

Myostatin/Activin Antagonist · Research Use

15–25%FST/MSTN ratio ↑

344 AACirculating isoform

ResearchPhase status

Research · No approved protocol

MT-1

α-MSH Analogue · FDA-Approved

16 mgImplant dose

13 AAPeptide lengthChawathe 2026

2019FDA approval

SQ Implant · 60-Day Release

01Mechanism of Action

Parameter

Follistatin-344

MT-1

Primary target

Myostatin (MSTN/GDF-8) and Activin A

Melanocortin-1 receptor (MC1R) on melanocytesLangan 2010

Pathway

FST-344 binds MSTN/Activin → prevents ActRIIB receptor engagement → disinhibits muscle anabolism

α-MSH analogue → MC1R activation → cAMP elevation → MITF transcription → eumelanin synthesis

Downstream effect

Elevated follistatin/myostatin ratio, increased muscle protein synthesis, attenuated muscle atrophy signalingJeong 2026

Increased melanogenesis, photoprotection, reduced UV sensitivityLangan 2010

Feedback intact?

Yes — indirect antagonist, preserves endogenous regulation

Yes — exogenous MC1R agonism does not suppress endogenous α-MSH production

Origin

Endogenous glycoprotein, 344-AA isoform lacking heparin-binding domain (vs FST-315)

Synthetic 13-AA peptidomimetic with norleucine (position 4) and D-phenylalanine (position 7) substitutions for metabolic stabilityChawathe 2026

Antibody development

Not documented in available trials (endogenous protein)

—

02Dosage Protocols

Parameter

Follistatin-344

MT-1

Clinical protocol

None — no approved dosing regimen

Follistatin-344 measured as endogenous biomarker, not administered exogenously in cited trials.

—

Research context

Endogenous modulation via exercise + nutrition

Resistance training + EAA intake elevated FST/MSTN ratio by 15–25% in 12-week RCT (older women).

—

Evidence basis

Human observational / biomarker studies

Phase 3 RCT / FDA-approved orphan drug

Half-life

Not established

Circulating isoform; lacks tissue-binding domain of FST-315.

—

Standard dose

—

16 mg subcutaneous implant

FDA-approved formulation (Scenesse).

Frequency

—

Every 60 days

Sustained release implant — no daily administration required.

Indication

—

Erythropoietic protoporphyria (EPP)

Narrow FDA approval — not licensed for cosmetic tanning.

Duration

—

Seasonal use (spring–autumn typical)

Aligned with peak UV exposure months.

Route

—

Subcutaneous implant — upper arm or abdomen

Stability

—

Norleucine/D-Phe substitutions enhance peptidase resistance

Modified structure vs endogenous α-MSH (Met⁴, L-Phe⁷).

03Metabolic / Fat Loss Evidence

Parameter

Follistatin-344

MT-1

Primary target

Muscle mass preservation, not direct lipolysis

—

Indirect fat effect

Increased lean mass → elevated resting metabolic rate

Not primary mechanism. Muscle-sparing during deficit.

—

Clinical evidence

Lorcaserin trial (6 mo) showed no MAFI axis changes during fat lossRamirez-Cisneros 2026

Suggests follistatin not primary driver of fat loss in weight-reduction interventions.

—

GLP-1RA studies

Liraglutide (35 days) — no significant MAFI axis modulation despite fat/lean changes

—

04Side Effects & Safety

Parameter

Follistatin-344

MT-1

Clinical safety data

None — no human exogenous administration trials in literature

—

Theoretical risks

Excessive myostatin inhibition → muscle overgrowth, impaired glucose tolerance

Based on myostatin-null animal models and clinical myostatin inhibitor trials.

—

Endogenous elevation (exercise)

No adverse effects reported in 12-week resistance + EAA trials

—

Cancer risk (theoretical)

Myostatin inhibition may promote tumor growth in malignancy (preclinical data)

—

Regulatory status

Not approved for human use — research peptide only

—

Nausea

—

Common (>10%) — mild, transient

Implant site reaction

—

Erythema, bruising, tenderness at insertion site

Hyperpigmentation

—

Generalised tanning (therapeutic effect), darkening of freckles/neviLangan 2010 Habbema 2017

Expected melanogenic response — complicates pigmented lesion surveillance.

Melanocytic changes

—

Rapid pigmentation of existing nevi; new melanocytic lesions reported with unregulated useHabbema 2017

Requires dermatologic monitoring; theoretical melanoma concern with chronic stimulation.

Headache

—

Occasional (MC1R-independent melanocortin effects)

Photosensitivity (paradoxical)

—

Rare phototoxic reactions despite melanin increase

Contamination risk (unregulated)

—

Impurity, infection, blood-borne virus transmission from illicit melanotan productsLangan 2010 Habbema 2017

Applies to internet/gym-sourced 'melanotan' — not FDA-approved Scenesse.

Absolute Contraindications

Follistatin-344

·Active malignancy
·No approved protocol — research use only

MT-1

·Hypersensitivity to afamelanotide or excipients
·Hepatic impairment (no safety data)
·Renal impairment (no safety data)

Relative Contraindications

Follistatin-344

·Insulin resistance / Type 2 diabetes (monitor glucose)
·Pregnancy / lactation (unknown safety profile)

MT-1

·History of melanoma or atypical nevi (melanocortin receptor stimulation concern)Habbema 2017
·Pregnancy/lactation (insufficient data)
·Photosensitive dermatoses (other than EPP)

05Administration Protocol

Parameter

Follistatin-344

MT-1

1. Regulatory status

Follistatin-344 is not approved for human administration. All cited studies measure endogenous serum follistatin as a biomarker, not as an exogenous therapeutic agent.

Performed by trained healthcare provider. Sterile technique. Small incision in upper arm (triceps) or lower abdomen using trocar. 16 mg rod (4 mm × 1.5 cm) inserted subcutaneously.

2. Endogenous modulation

Resistance exercise combined with essential amino acid (EAA) supplementation elevated the follistatin/myostatin ratio by 15–25% in 12-week randomized trials. Protein intake (1.2–1.5 g/kg/day) synergizes with training to upregulate endogenous follistatin.

Pressure applied post-insertion. Sterile dressing × 24 hrs. Avoid strenuous activity for 24–48 hrs to prevent extrusion.

3. Measurement context

Serum follistatin and follistatin/myostatin ratio are used diagnostically in sarcopenia screening and as biomarkers of muscle anabolic balance in clinical trials.

Slow biodegradable polymer matrix releases afamelanotide over 60 days, maintaining therapeutic plasma levels without daily dosing.

4. Research consideration

Gene therapy and recombinant follistatin delivery are under preclinical investigation for muscular dystrophy and sarcopenia. No human safety or efficacy data for exogenous FST-344 administration.

New implant every 60 days during high UV season (spring–autumn in temperate climates). Rotate implant sites to avoid scarring.

5. Monitoring

—

Baseline and periodic dermatologic exams to document pigmented lesions. Patient education on self-examination for new/changing nevi.

06Stack Synergy

Follistatin-344

+ BPC-157

Multi-pathway

View BPC-157 →

Follistatin-344 (myostatin antagonist) and BPC-157 (tissue repair peptide) address complementary pathways in muscle recovery. FST-344 promotes muscle protein synthesis by disinhibiting myostatin signaling, while BPC-157 accelerates healing of tendons, ligaments, and microtears via angiogenesis and collagen synthesis. Combined, they may support both hypertrophy and structural repair during high-volume training or injury recovery.

Follistatin-344: No approved protocol — endogenous modulation via resistance exercise + EAA
BPC-157: 250–500 mcg SQ · twice daily · near injury site or systemic
Duration: 4–8 weeks
Primary benefit: Muscle hypertrophy + accelerated soft tissue repair

+ TB-500

Moderate

View TB-500 →

TB-500 (thymosin beta-4 fragment) promotes cell migration, angiogenesis, and anti-inflammatory signaling in muscle and connective tissue. Follistatin-344's anabolic signaling may synergize with TB-500's regenerative effects during muscle damage or overtraining, particularly in older adults where both myostatin inhibition and tissue repair are rate-limiting.

Follistatin-344: Endogenous upregulation (resistance training + protein)
TB-500: 2–5 mg SQ · twice weekly · loading phase 4 weeks, then maintenance
Frequency: Twice weekly TB-500, daily training stimulus for FST
Primary benefit: Enhanced recovery, reduced inflammation, muscle growth support

MT-1

— no documented stacks