Side-by-side · Research reference

Follistatin-344vsSurvodutide

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 3HUMAN-REVIEWED25/54 cited

Follistatin-344

Myostatin/Activin Antagonist · Research Use

15–25%FST/MSTN ratio ↑

344 AACirculating isoform

ResearchPhase status

Research · No approved protocol

Survodutide

GLP-1/Glucagon Dual Agonist · Phase 3

Once weeklyFrequency

Phase 3Development stageRubino 2026

GLP-1/GCGRDual targetZimmermann 2026

SQ · Once Weekly

01Mechanism of Action

Parameter

Follistatin-344

Survodutide

Primary target

Myostatin (MSTN/GDF-8) and Activin A

GLP-1 receptor and glucagon receptor (GCGR)Yathindra 2026 Zimmermann 2026

Pathway

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

Central: CVOs → hypothalamic appetite regulation. Peripheral: GLP-1R → incretin effect; GCGR → hepatic lipid metabolism, energy expenditureZimmermann 2026 Long 2026

Downstream effect

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

Decreased energy intake, increased energy expenditure, improved glucose homeostasis, hepatic fat reductionZimmermann 2026 Yathindra 2026

Feedback intact?

Yes — indirect antagonist, preserves endogenous regulation

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Origin

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

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Antibody development

Not documented in available trials (endogenous protein)

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02Dosage Protocols

Parameter

Follistatin-344

Survodutide

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).

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Evidence basis

Human observational / biomarker studies

Phase 2 RCT (obesity) · Phase 3 ongoing

Half-life

Not established

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

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Standard dose

—

Not yet disclosed (Phase 3 ongoing)

SYNCHRONIZE Phase 3 program underway.Rubino 2026

Frequency

—

Once weekly

Route

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SubcutaneousYathindra 2026

Phase 2 findings

—

Significant weight loss and metabolic marker improvementYathindra 2026

MASH indication

—

Under investigation for MASH-cirrhosisPatil 2026 Andonie 2026

03Metabolic / Fat Loss Evidence

Parameter

Follistatin-344

Survodutide

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

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Primary fat target

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Total body weight, visceral adipose tissue

Weight loss mechanism

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Dual action: decreased energy intake + increased energy expenditureZimmermann 2026

Phase 2 efficacy

—

Significant weight loss demonstrated

Specific percentage not disclosed in abstracts.

Metabolic markers

—

Improvements in ALT, AST, LDL levels; significant ALT reduction (MD -22.10 vs placebo)Yathindra 2026 Abulehia 2026 Andonie 2026

MRI-PDFF reduction

—

Hepatic fat reduction demonstrated in MASH trialsAndonie 2026

Network meta-analysis

—

Favorable efficacy profile vs other glucagon receptor agonists

Hepatic requirement

—

Hepatic GCGR required for maximal weight loss and metabolic effectsLong 2026

Energy expenditure

—

Increased energy expenditure contributes to weight lossZimmermann 2026

Comparative efficacy

—

Network meta-analysis shows competitive efficacy in GRA class

04Side Effects & Safety

Parameter

Follistatin-344

Survodutide

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.

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Endogenous elevation (exercise)

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

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Cancer risk (theoretical)

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

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Regulatory status

Not approved for human use — research peptide only

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GI symptoms

—

Diarrhea, nausea, fatigue — class effect of GLP-1 agonists

Safety profile

—

Network meta-analysis: comparable safety to other GRAs

Serious adverse events

—

Monitored in Phase 2/3; no unique safety signals reported

Detailed SAE data pending Phase 3 completion.

Injection site reactions

—

Expected with subcutaneous administration

Glucagon-related effects

—

Potential for tachycardia, increased blood pressure — theoretical glucagon effect

Absolute Contraindications

Follistatin-344

·Active malignancy
·No approved protocol — research use only

Survodutide

·Personal or family history of medullary thyroid carcinoma (class effect)
·Multiple endocrine neoplasia syndrome type 2

Relative Contraindications

Follistatin-344

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

Survodutide

·Severe GI disease (inflammatory bowel disease, gastroparesis)
·History of pancreatitis
·Cardiovascular disease (monitor closely for glucagon effects)

05Administration Protocol

Parameter

Follistatin-344

Survodutide

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.

Specific reconstitution protocol not yet publicly disclosed. Follow manufacturer instructions upon approval.

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.

Subcutaneous — abdomen, thigh, or upper arm. Rotate sites weekly to minimize injection site reactions.

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.

Once weekly, same day each week. Can be administered at any time of day, with or without meals.

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.

Store refrigerated (2–8 °C) until use. Do not freeze. Protect from light. Specific reconstituted storage duration pending labeling.

5. Needle

—

Subcutaneous injection with appropriate gauge needle (typically 27–31G). Use sterile technique.

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

Survodutide

— no documented stacks