Side-by-side · Research reference
CagrilintidevsFollistatin-344
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 3HUMAN-REVIEWED35/64 cited
BHuman-MechanisticHUMAN-REVIEWED4/58 cited
Follistatin-344
Myostatin/Activin Antagonist · Research Use
15–25%FST/MSTN ratio ↑
344 AACirculating isoform
ResearchPhase status
Research · No approved protocol
01Mechanism of Action
Parameter
Cagrilintide
Follistatin-344
Primary target
Amylin receptor (AMYR) and calcitonin receptor (CTR) heterodimeric complexesBailey 2026
Myostatin (MSTN/GDF-8) and Activin A
Pathway
AMYR/CTR agonism → Central satiety signaling → Reduced food intake, delayed gastric emptying, suppressed glucagonBailey 2026
FST-344 binds MSTN/Activin → prevents ActRIIB receptor engagement → disinhibits muscle anabolism
Downstream effect
Central satiety induction, prandial glucagon suppression, reduced caloric intake, weight loss, improved glycemic controlBailey 2026Yamauchi 2026
Elevated follistatin/myostatin ratio, increased muscle protein synthesis, attenuated muscle atrophy signalingJeong 2026
Feedback intact?
Yes — acts via physiological amylin pathways
Yes — indirect antagonist, preserves endogenous regulation
Origin
Second-generation non-aggregating long-acting amylin analogue designed for once-weekly dosingBailey 2026
Endogenous glycoprotein, 344-AA isoform lacking heparin-binding domain (vs FST-315)
Antibody development
—
Not documented in available trials (endogenous protein)
02Dosage Protocols
Parameter
Cagrilintide
Follistatin-344
Standard dose (combination)
Cagrilintide 2.4 mg + Semaglutide 2.4 mg (CagriSema)Yamauchi 2026
Phase 3 REDEFINE 5 trial dosing.
—
Monotherapy dosing
Dose-dependent, under investigation
Monotherapy trials reported in meta-analysis.
—
Evidence basis
Phase 3 RCT (REDEFINE 5), meta-analysis of 3 RCTs (n=3545)Yamauchi 2026Ahmed 2026
Human observational / biomarker studies
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.
03Metabolic / Fat Loss Evidence
Parameter
Cagrilintide
Follistatin-344
Weight loss vs semaglutide
7.47% greater percentage weight lossAhmed 2026
CagriSema combination vs semaglutide monotherapy (meta-analysis).
—
Absolute weight change
Significantly greater absolute weight reductionAhmed 2026
Mean difference favoring combination therapy.
—
Glycemic benefit
Reduced fasting glucose and HbA1cAhmed 2026
Synergistic effect with semaglutide in combination.
—
Body composition
Predominant fat loss with weight reduction
—
Mitochondrial function
In vitro effects on skeletal muscle mitochondria under metabolic stress conditionsOld 2026
C2C12 myotube study; clinical relevance under investigation.
—
Key publications
REDEFINE 5 (Yamauchi 2026) · Ahmed meta-analysis 2026 · Bailey review 2026Yamauchi 2026Ahmed 2026Bailey 2026
—
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
Cagrilintide
Follistatin-344
Gastrointestinal
Nausea, diarrhea (common with incretin-based therapies)Pardali 2026
Dietary management and nutritional monitoring recommended.
—
Injection site reactions
Local reactions possible with subcutaneous administration
—
Safety profile
Generally consistent with incretin-based therapies
Phase 3 and meta-analysis safety data.
—
Tolerability
Tolerability considerations similar to GLP-1RAs
—
Muscle preservation
Lean mass considerations during weight loss
In vitro mitochondrial effects observed; clinical impact under investigation.
—
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
Absolute Contraindications
Cagrilintide
- ·Hypersensitivity to cagrilintide or formulation components
Follistatin-344
- ·Active malignancy
- ·No approved protocol — research use only
Relative Contraindications
Cagrilintide
- ·Severe gastrointestinal disease
- ·History of pancreatitis (incretin-based therapy consideration)
Follistatin-344
- ·Insulin resistance / Type 2 diabetes (monitor glucose)
- ·Pregnancy / lactation (unknown safety profile)
05Administration Protocol
Parameter
Cagrilintide
Follistatin-344
1. Dosing frequency
Once-weekly subcutaneous injection. Long-acting formulation designed for weekly administration schedule.Bailey 2026
Follistatin-344 is not approved for human administration. All cited studies measure endogenous serum follistatin as a biomarker, not as an exogenous therapeutic agent.
2. Combination form
Co-formulated with semaglutide as CagriSema for single weekly injection combining amylin and GLP-1 receptor agonism.Yamauchi 2026Bailey 2026
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.
3. Injection site
Subcutaneous — typically abdomen, thigh, or upper arm. Rotate injection sites weekly to minimize local reactions.
Serum follistatin and follistatin/myostatin ratio are used diagnostically in sarcopenia screening and as biomarkers of muscle anabolic balance in clinical trials.
4. Storage
Refrigerate 2–8°C. Follow product-specific storage instructions for pre-filled pens or vials. Protect from light.
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.
5. Dietary considerations
Nutritional monitoring recommended during treatment. Dietary management strategies important for tolerability and outcomes.Pardali 2026
—
06Stack Synergy
Cagrilintide
+ Semaglutide
StrongCagrilintide (amylin receptor agonist) and semaglutide (GLP-1 receptor agonist) act on distinct receptor systems to produce synergistic weight loss through complementary mechanisms — central satiety via amylin pathways plus incretin-mediated glucose control and appetite suppression via GLP-1. Co-formulated as CagriSema, this combination demonstrates 7.5% greater weight loss versus semaglutide monotherapy in Phase 3 trials with additional benefits on glycemic control and lipid parameters.
- CagriSema
- Cagrilintide 2.4 mg + Semaglutide 2.4 mg
- Frequency
- Once weekly subcutaneous
- Duration
- 26–52 weeks (trial data)
- Primary benefit
- Enhanced weight loss, improved glycemic control, multi-pathway metabolic modulation
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