Side-by-side · Research reference

Follistatin-344vsTesofensine

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 3AUTO-DRAFTED10/40 cited

Follistatin-344

Myostatin/Activin Antagonist · Research Use

15–25%FST/MSTN ratio ↑

344 AACirculating isoform

ResearchPhase status

Research · No approved protocol

Tesofensine

SNDRI · Phase 3 obesity candidate

0.25–0.5 mgDaily doseAstrup 2008

9.2 kgWeight ↓ (24 wk)Astrup 2008

Phase 3Evidence levelAstrup 2008

Oral · Once daily morning

01Mechanism of Action

Parameter

Follistatin-344

Tesofensine

Primary target

Myostatin (MSTN/GDF-8) and Activin A

Serotonin / norepinephrine / dopamine transporters (SERT / NET / DAT)Astrup 2008

Pathway

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

Triple monoamine reuptake inhibition → ↑synaptic 5-HT, NE, DA → appetite suppression + thermogenesisAstrup 2008

Downstream effect

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

Strong appetite suppression, mild thermogenic effect, weight lossAstrup 2008

Feedback intact?

Yes — indirect antagonist, preserves endogenous regulation

—

Origin

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

Small molecule developed by NeuroSearch (Denmark) for CNS indications, repurposed for obesityAstrup 2008

Antibody development

Not documented in available trials (endogenous protein)

—

02Dosage Protocols

Parameter

Follistatin-344

Tesofensine

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 2b + ongoing Phase 3Astrup 2008

Half-life

Not established

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

~9 days (very long)

Standard dose

—

0.25–0.5 mg / dayAstrup 2008

Frequency

—

Once daily, morning

Lower / starter dose

—

0.125 mg / day

Duration

—

24 weeks per studied cycle

Form

—

Oral capsule

Timing

—

Morning to avoid sleep disruption

03Metabolic / Fat Loss Evidence

Parameter

Follistatin-344

Tesofensine

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

Tesofensine

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

—

Heart rate / BP

—

Dose-dependent ↑ HR + BPAstrup 2008

Insomnia

—

Dose-related; mitigate with morning timing

Dry mouth

—

Common

Nausea

—

Common

Mood changes

—

Anxiety / agitation possible

Cardiovascular events

—

Phase 3 trial monitoring; not yet FDA-cleared

Pregnancy / OB

—

Contraindicated

Absolute Contraindications

Follistatin-344

·Active malignancy
·No approved protocol — research use only

Tesofensine

·Pregnancy / breastfeeding
·Severe cardiovascular disease
·Concurrent MAOI use

Relative Contraindications

Follistatin-344

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

Tesofensine

·Hypertension
·Anxiety disorder
·Insomnia

05Administration Protocol

Parameter

Follistatin-344

Tesofensine

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.

Oral capsule (investigational; not commercial).

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.

Swallow whole with water, morning only.

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.

Morning to mitigate insomnia. Do not dose evening.

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.

Room temp ≤25 °C, dry place.

5. Caveat

—

Monitor BP + HR + mood. Avoid stimulants + MAOIs.

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

Tesofensine

— no documented stacks