Side-by-side · Research reference
Follistatin-344vsTB-500
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-REVIEWED8/46 cited
Follistatin-344
Myostatin/Activin Antagonist · Research Use
15–25%FST/MSTN ratio ↑
344 AACirculating isoform
ResearchPhase status
Research · No approved protocol
TB-500
Thymosin β4 fragment · Healing
SQ or IM · Multiple sites · 2–3×/week
01Mechanism of Action
Parameter
Follistatin-344
TB-500
Primary target
Myostatin (MSTN/GDF-8) and Activin A
G-actin (sequestering) + cell-surface integrinsGoldstein 2012
Pathway
FST-344 binds MSTN/Activin → prevents ActRIIB receptor engagement → disinhibits muscle anabolism
Actin remodelling → cell migration; integrin-linked signaling → angiogenesis; anti-inflammatory cytokine modulationGoldstein 2012Malinda 1999
Downstream effect
Elevated follistatin/myostatin ratio, increased muscle protein synthesis, attenuated muscle atrophy signalingJeong 2026
Accelerated wound healing, endothelial migration, hair follicle regeneration, cardiac repair (preclinical)Goldstein 2012
Feedback intact?
Yes — indirect antagonist, preserves endogenous regulation
Endogenous protein at baseline; supplementation amplifies
Origin
Endogenous glycoprotein, 344-AA isoform lacking heparin-binding domain (vs FST-315)
17-AA active fragment of endogenous 43-AA thymosin β4 (TMSB4X gene)Goldstein 2012
Antibody development
Not documented in available trials (endogenous protein)
—
02Dosage Protocols
Parameter
Follistatin-344
TB-500
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
Animal-strong + Phase 2 dermal/ocular trialsGoldstein 2012
Half-life
Not established
Circulating isoform; lacks tissue-binding domain of FST-315.
~2 hours (estimated; tissue uptake longer)
Standard dose
—
2 mg per injectionGoldstein 2012
Anecdotal community range; clinical Phase 2 trials used 70–840 mcg/kg IV.
Frequency
—
2× per week (loading); then 1× per week (maintenance)
Lower / starter dose
—
1 mg per injection
Duration
—
4–8 weeks loading; longer maintenance for chronic injury
Reconstitution
—
Bacteriostatic water, 1–2 mL per 5 mg vial
Timing
—
Evening or pre-rest preferred (anecdotal)
03Metabolic / Fat Loss Evidence
Parameter
Follistatin-344
TB-500
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
TB-500
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
—
Injection site reaction
—
Mild erythema, transient pain
GI symptoms
—
Rare nausea (anecdotal)
Cancer risk
—
Theoretical via angiogenesis pathway
Lethargy / fatigue
—
Reported anecdotally during loading phase
Antibody formation
—
No data (no long-term human trials)
Pregnancy / OB
—
Avoid
Long-term safety
—
Unknown beyond Phase 2
Absolute Contraindications
Follistatin-344
- ·Active malignancy
- ·No approved protocol — research use only
TB-500
- ·Active malignancy (theoretical angiogenesis concern)
- ·Pregnancy / breastfeeding
Relative Contraindications
Follistatin-344
- ·Insulin resistance / Type 2 diabetes (monitor glucose)
- ·Pregnancy / lactation (unknown safety profile)
TB-500
- ·Cancer history
- ·Concurrent VEGF inhibitor therapy
05Administration Protocol
Parameter
Follistatin-344
TB-500
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 1–2 mL bacteriostatic water to 5 mg vial → 2.5–5 mg/mL. Roll gently.
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 near injury site (preferred), or systemic SQ (abdomen). 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.
Evening or pre-sleep is most common anecdotal timing.
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
—
27–31G, 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
TB-500
+ BPC-157
StrongTB-500 and BPC-157 cover complementary halves of tissue repair: BPC-157 upregulates VEGFR2-driven angiogenesis and fibroblast outgrowth; TB-500 sequesters G-actin to enable endothelial / epithelial migration. The anecdotal canonical "healing stack" — pairs especially well for tendon and ligament injuries.
- TB-500
- 2 mg SQ · 2× per week
- BPC-157
- 250–500 mcg SQ · daily
- Primary benefit
- Combined angiogenesis + cell migration for tendon/ligament/muscle repair