Side-by-side · Research reference

Follistatin-344vsGonadorelin

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-REVIEWED7/61 cited

Follistatin-344

Myostatin/Activin Antagonist · Research Use

15–25%FST/MSTN ratio ↑

344 AACirculating isoform

ResearchPhase status

Research · No approved protocol

Gonadorelin

GnRH Analogue · Diagnostic & Therapeutic

90 minPulsatile interval

73%Ovulation restorationTadesse 2026

2–4 minPlasma half-life

IV / SQ · Pulsatile Pump (Therapeutic) · Single Bolus (Diagnostic)

01Mechanism of Action

Parameter

Follistatin-344

Gonadorelin

Primary target

Myostatin (MSTN/GDF-8) and Activin A

GnRH receptors on anterior pituitary gonadotropes

Pathway

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

GnRH → Pituitary gonadotrope → LH/FSH secretion → Gonadal steroidogenesisSharma 2026

Downstream effect

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

Pulsatile LH/FSH release stimulates testicular testosterone or ovarian estradiol/progesterone synthesis; initiates folliculogenesis and spermatogenesisRobin 2026 Sharma 2026

Feedback intact?

Yes — indirect antagonist, preserves endogenous regulation

Yes — pulsatile delivery preserves negative feedback loops; continuous exposure desensitizes receptors

Origin

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

Synthetic decapeptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) identical to native hypothalamic GnRH

Antibody development

Not documented in available trials (endogenous protein)

—

02Dosage Protocols

Parameter

Follistatin-344

Gonadorelin

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

RCT / Expert consensus

Half-life

Not established

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

2–4 minutes (plasma)

Necessitates frequent pulsatile administration.

Diagnostic test (pituitary function)

—

100 mcg IV or SQ bolus

Measure baseline LH/FSH, then 30/60/90 min post-injection. Normal response: LH ≥2× baseline.

Therapeutic (hypothalamic hypogonadism)

—

5–20 mcg IV bolus every 90–120 minutes

Requires portable pulsatile pump. Dose individualized to achieve normal gonadotropin pulsatility.Robin 2026

Pulsatile interval

—

90 minutes (females) · 120 minutes (males)

Mimics physiological GnRH pulse frequency.

Route

—

IV preferred (therapeutic) · SQ acceptable (diagnostic)

Duration

—

Continuous until pregnancy achieved or fertility goals met

3–6 month courses typical for ovulation induction.

Alternative protocols

—

Exogenous gonadotropins (hCG/hMG) often preferred due to convenience vs pump requirement

03Metabolic / Fat Loss Evidence

Parameter

Follistatin-344

Gonadorelin

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

—

Fat loss mechanism

—

None — gonadorelin acts exclusively on reproductive axis

Indirect metabolic effects

—

Restoration of sex hormones may normalize body composition in hypogonadal states

Effect mediated by downstream testosterone/estradiol, not GnRH itself.

04Side Effects & Safety

Parameter

Follistatin-344

Gonadorelin

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

—

Erythema, irritation (pulsatile pump catheter site)

Headache

—

Common with bolus administration

Nausea / abdominal discomfort

—

Transient, dose-related

Ovarian hyperstimulation syndrome (OHSS)

—

Risk with ovulation induction protocols; monitor follicular development via ultrasound

Multiple gestation

—

Increased risk with fertility protocols (twins ~10–15%)

Anaphylaxis

—

Rare hypersensitivity reaction

Pump malfunction / infection

—

Mechanical failure or catheter-site infection with long-term IV pump use

Receptor desensitization

—

Continuous (non-pulsatile) exposure paradoxically suppresses gonadotropinsRobin 2026

Absolute Contraindications

Follistatin-344

·Active malignancy
·No approved protocol — research use only

Gonadorelin

·Pregnancy (except therapeutic infertility protocols)
·Hypersensitivity to gonadorelin or excipients
·Hormone-dependent tumors (prostate, breast) — risk of tumor stimulation via sex hormone elevation

Relative Contraindications

Follistatin-344

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

Gonadorelin

·Ovarian cysts or PCOS (monitor for OHSS)
·Pituitary adenoma or other sellar mass (may worsen with gonadotropin surge)

05Administration Protocol

Parameter

Follistatin-344

Gonadorelin

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.

Administer 100 mcg IV or SQ bolus. Draw baseline LH/FSH, then at 30, 60, 90 minutes. Normal response: LH ≥2× baseline, FSH modest rise. Blunted response suggests pituitary pathology; exaggerated response may indicate primary hypogonadism.

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.

Requires programmable infusion pump with IV catheter. Set pulse interval to 90 min (females) or 120 min (males). Bolus dose 5–20 mcg per pulse. Pump worn continuously; catheter site rotated every 48–72 hrs to prevent infection.

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.

Lyophilised gonadorelin reconstituted with sterile saline or provided diluent. Typically 0.8–3.2 mg dissolved in 8 mL for pump reservoir. Solution stable 7–14 days refrigerated.

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.

For fertility protocols: ultrasound follicular tracking + serial estradiol/LH measurements. Adjust pulse dose to achieve mid-follicular LH 5–10 IU/L. Ovulation confirmed by progesterone rise or ultrasound.

5. Timing

—

Pulsatile therapy initiated at any point in cycle. Diagnostic test performed in morning (higher baseline LH). For ovulation induction, treatment begins early follicular phase.

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

Gonadorelin

+ hCG (Human Chorionic Gonadotropin)

Multi-pathway

View hCG (Human Chorionic Gonadotropin) →

In hypogonadotropic hypogonadism protocols, gonadorelin restores pituitary LH/FSH pulsatility, while exogenous hCG directly stimulates Leydig cells (acting as LH mimetic) to maintain testosterone production. This dual approach ensures both central axis restoration and immediate gonadal steroidogenesis, preventing testicular atrophy during fertility treatment. hCG's longer half-life (24–36 hrs) complements gonadorelin's pulsatile short-acting profile.

Gonadorelin: 5–10 mcg IV every 120 min (pulsatile pump)
hCG: 1500–2000 IU SQ · 2–3× per week
Duration: 12–24 weeks for spermatogenesis induction
Primary benefit: Fertility restoration in hypothalamic hypogonadism with maintained testicular function