Side-by-side · Research reference
Follistatin-344vsGHRP-2
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
BPhase 2HUMAN-REVIEWED15/42 cited
Follistatin-344
Myostatin/Activin Antagonist · Research Use
15–25%FST/MSTN ratio ↑
344 AACirculating isoform
ResearchPhase status
Research · No approved protocol
GHRP-2
Hexapeptide GHRP · Phase 2 (clinical diagnostic)
SQ · Multiple sites · 1–3×/day
01Mechanism of Action
Parameter
Follistatin-344
GHRP-2
Primary target
Myostatin (MSTN/GDF-8) and Activin A
Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990
Pathway
FST-344 binds MSTN/Activin → prevents ActRIIB receptor engagement → disinhibits muscle anabolism
GHS-R1a → Gαq → Ca²⁺ → GH vesicle exocytosisBowers 2002
Downstream effect
Elevated follistatin/myostatin ratio, increased muscle protein synthesis, attenuated muscle atrophy signalingJeong 2026
Strong GH pulse + IGF-1 elevation; appetite increase via ghrelin agonismBowers 2002
Feedback intact?
Yes — indirect antagonist, preserves endogenous regulation
Yes, with somatostatin feedback active
Origin
Endogenous glycoprotein, 344-AA isoform lacking heparin-binding domain (vs FST-315)
Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 1990
Antibody development
Not documented in available trials (endogenous protein)
—
02Dosage Protocols
Parameter
Follistatin-344
GHRP-2
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).
—
Half-life
Not established
Circulating isoform; lacks tissue-binding domain of FST-315.
~30 minMalagón 1999
Frequency
—
1–3× per day
Lower / starter dose
—
50 mcg per dose
Duration
—
8–12 weeks on / 4 off (anecdotal)
Reconstitution
—
Bacteriostatic water
Timing
—
Pre-sleep + fasted preferred
03Metabolic / Fat Loss Evidence
Parameter
Follistatin-344
GHRP-2
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
GHRP-2
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
—
Prolactin elevation
—
Mild but measurable
Hunger
—
Strong appetite increase
Injection site reaction
—
Mild erythema
IGF-1 elevation
—
Strong; monitor with chronic high-dose use
Cancer risk
—
Contraindicated in active malignancy
Pregnancy / OB
—
Avoid
Absolute Contraindications
Follistatin-344
- ·Active malignancy
- ·No approved protocol — research use only
GHRP-2
- ·Active malignancy
- ·Pregnancy / breastfeeding
Relative Contraindications
Follistatin-344
- ·Insulin resistance / Type 2 diabetes (monitor glucose)
- ·Pregnancy / lactation (unknown safety profile)
GHRP-2
- ·Untreated diabetes
05Administration Protocol
Parameter
Follistatin-344
GHRP-2
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.
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.
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.
SQ — abdomen or thigh. Rotate sites.
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.
Pre-sleep + fasted preferred.
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.
Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.
5. Needle
—
29–31G, 4–8 mm insulin syringe.
06Stack Synergy
Follistatin-344
+ BPC-157
Multi-pathwayFollistatin-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
ModerateTB-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
GHRP-2
+ CJC-1295 (no DAC)
StrongGHRP-2 + CJC-1295-no-DAC is a higher-amplitude alternative to the ipamorelin + CJC-1295 stack. GHRP-2 produces a stronger pulse but with cortisol + prolactin signal — choose when maximum GH amplitude is the goal and the side-effect tolerance is acceptable.
- GHRP-2
- 100–200 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- High-amplitude GH pulse, body composition