Side-by-side · Research reference
CagrilintidevsRetatrutide
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
BPhase 2HUMAN-REVIEWED10/41 cited
Retatrutide
Triple-receptor agonist · Phase 3
SQ · Abdomen · Once weekly
01Mechanism of Action
Parameter
Cagrilintide
Retatrutide
Primary target
Amylin receptor (AMYR) and calcitonin receptor (CTR) heterodimeric complexesBailey 2026
GLP-1R + GIPR + Glucagon receptor (triple agonism)Jastreboff 2023
Pathway
AMYR/CTR agonism → Central satiety signaling → Reduced food intake, delayed gastric emptying, suppressed glucagonBailey 2026
Triple-receptor activation → ↑insulin (GLP-1+GIP), ↓gastric emptying, ↑lipid handling, ↑energy expenditure (glucagon component)Jastreboff 2023
Downstream effect
Central satiety induction, prandial glucagon suppression, reduced caloric intake, weight loss, improved glycemic controlBailey 2026Yamauchi 2026
Maximal weight loss across class. Glucagon component drives lipolysis and energy expenditure beyond GLP-1+GIP aloneJastreboff 2023
Feedback intact?
Yes — acts via physiological amylin pathways
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Origin
Second-generation non-aggregating long-acting amylin analogue designed for once-weekly dosingBailey 2026
Synthetic peptide engineered for balanced affinity at three incretin / glucagon receptorsJastreboff 2023
Antibody development
—
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02Dosage Protocols
Parameter
Cagrilintide
Retatrutide
Standard dose (combination)
Cagrilintide 2.4 mg + Semaglutide 2.4 mg (CagriSema)Yamauchi 2026
Phase 3 REDEFINE 5 trial dosing.
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Monotherapy dosing
Dose-dependent, under investigation
Monotherapy trials reported in meta-analysis.
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Evidence basis
Phase 3 RCT (REDEFINE 5), meta-analysis of 3 RCTs (n=3545)Yamauchi 2026Ahmed 2026
Phase 2 trial; Phase 3 ongoingJastreboff 2023
Titration schedule
—
2 mg → 4 mg → 8 mg → 12 mg over 16 weeks
Reconstitution
—
Investigational; not commercially available
Timing
—
Any time of day
Half-life
—
~6 days (estimated from class)
03Metabolic / Fat Loss Evidence
Parameter
Cagrilintide
Retatrutide
Weight loss vs semaglutide
7.47% greater percentage weight lossAhmed 2026
CagriSema combination vs semaglutide monotherapy (meta-analysis).
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Absolute weight change
Significantly greater absolute weight reductionAhmed 2026
Mean difference favoring combination therapy.
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Glycemic benefit
Reduced fasting glucose and HbA1cAhmed 2026
Synergistic effect with semaglutide in combination.
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Body composition
Predominant fat loss with weight reduction
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Mitochondrial function
In vitro effects on skeletal muscle mitochondria under metabolic stress conditionsOld 2026
C2C12 myotube study; clinical relevance under investigation.
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Key publications
REDEFINE 5 (Yamauchi 2026) · Ahmed meta-analysis 2026 · Bailey review 2026Yamauchi 2026Ahmed 2026Bailey 2026
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04Side Effects & Safety
Parameter
Cagrilintide
Retatrutide
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
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Safety profile
Generally consistent with incretin-based therapies
Phase 3 and meta-analysis safety data.
—
Tolerability
Tolerability considerations similar to GLP-1RAs
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Muscle preservation
Lean mass considerations during weight loss
In vitro mitochondrial effects observed; clinical impact under investigation.
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Glucose handling
—
Glycemic improvement; rare hyperglycemia from glucagon component
Pancreatitis risk
—
Class warning
Thyroid C-cell tumours
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Class warning (presumed)
Pregnancy / OB
—
Avoid (insufficient data)
Absolute Contraindications
Cagrilintide
- ·Hypersensitivity to cagrilintide or formulation components
Retatrutide
- ·MTC personal or family history (presumed class effect)
- ·Pregnancy / breastfeeding
Relative Contraindications
Cagrilintide
- ·Severe gastrointestinal disease
- ·History of pancreatitis (incretin-based therapy consideration)
Retatrutide
- ·Severe gastroparesis
- ·History of pancreatitis
- ·Severe cardiovascular disease (HR signal)
05Administration Protocol
Parameter
Cagrilintide
Retatrutide
1. Dosing frequency
Once-weekly subcutaneous injection. Long-acting formulation designed for weekly administration schedule.Bailey 2026
Investigational peptide. Research vials reconstituted with bacteriostatic water per label.
2. Combination form
Co-formulated with semaglutide as CagriSema for single weekly injection combining amylin and GLP-1 receptor agonism.Yamauchi 2026Bailey 2026
SQ — abdomen, thigh, or upper arm. Rotate weekly.
3. Injection site
Subcutaneous — typically abdomen, thigh, or upper arm. Rotate injection sites weekly to minimize local reactions.
Once weekly, same day.
4. Storage
Refrigerate 2–8°C. Follow product-specific storage instructions for pre-filled pens or vials. Protect from light.
Refrigerate 2–8 °C. Light-protected.
5. Dietary considerations
Nutritional monitoring recommended during treatment. Dietary management strategies important for tolerability and outcomes.Pardali 2026
27–31G, 4–8 mm insulin syringe.
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
Retatrutide
— no documented stacks