Enicepatide vs Retatrutide: Dual Agonist vs Triple Agonist
A comparison of enicepatide (Roche CT-388), a GLP-1/GIP dual agonist, and retatrutide (Eli Lilly LY3437943), a GLP-1/GIP/glucagon triple agonist. Both are investigational once-weekly injectables for obesity. Updated June 2026 with enicepatide Phase 2 CT388-103 (~22.5% placebo-adjusted at 48 weeks) and retatrutide Phase 3 TRIUMPH-1 (28.3% absolute at 12 mg / 80 weeks).
Last updated: 2026-06-06
| Property | Enicepatide | Retatrutide |
|---|---|---|
| Evidence Level | Level B | Level B |
| Regulatory Status | Investigational | Investigational |
| Category | Weight Management | Weight Management |
| Administration | Injectable | Injectable |
| Onset Time | Weeks (appetite signaling onset); peak weight loss reported at 48 weeks in Phase 2 | Weeks (appetite suppression onset); peak weight loss at 48+ weeks |
| Half-Life | Designed for once-weekly subcutaneous administration | Approximately 7 days (once-weekly dosing design) |
| Key Mechanism | Enicepatide is engineered to activate two incretin receptors — the glucagon-like peptide-1 (GLP-1) receptor and the g... | Retatrutide's effects arise from simultaneous activation of three incretin and metabolic hormone receptor pathways: ... |
Enicepatide
- Evidence Level
- Level B
- Regulatory Status
- Investigational
- Category
- Weight Management
- Administration
- Injectable
- Onset Time
- Weeks (appetite signaling onset); peak weight loss reported at 48 weeks in Phase 2
- Half-Life
- Designed for once-weekly subcutaneous administration
- Key Mechanism
- Enicepatide is engineered to activate two incretin receptors — the glucagon-like peptide-1 (GLP-1) receptor and the g...
Retatrutide
- Evidence Level
- Level B
- Regulatory Status
- Investigational
- Category
- Weight Management
- Administration
- Injectable
- Onset Time
- Weeks (appetite suppression onset); peak weight loss at 48+ weeks
- Half-Life
- Approximately 7 days (once-weekly dosing design)
- Key Mechanism
- Retatrutide's effects arise from simultaneous activation of three incretin and metabolic hormone receptor pathways: ...
Key Differences
Enicepatide and retatrutide are both investigational obesity peptides from major pharmaceutical pipelines, but they sit one receptor apart — and that difference defines the comparison. Enicepatide adds GIP to GLP-1; retatrutide adds both GIP and glucagon. Retatrutide is also further along in development.
Receptor Pharmacology
Enicepatide is a dual GLP-1/GIP receptor agonist — the same receptor pair as tirzepatide, with a biased-signalling design intended to limit receptor desensitization. Its mechanism centers on appetite suppression and improved glucose handling through incretin co-agonism.
Retatrutide is a triple agonist of GLP-1, GIP, and the glucagon receptor. The added glucagon receptor agonism is the structural innovation: alongside the appetite-suppressing incretin effects, controlled glucagon activation is associated with increased energy expenditure and shifts in hepatic substrate use. The triple-agonist hypothesis is that incretin-driven appetite reduction plus glucagon-driven energy expenditure produces additive weight loss beyond what dual agonism achieves.
Weight Loss Magnitude — Measurement Differences Matter
Enicepatide's Phase 2 CT388-103 trial (ADA 2026) reported approximately 22.5% placebo-adjusted mean weight loss at 48 weeks. Retatrutide's Phase 2 trial (Jastreboff et al., NEJM 2023) reported approximately 24.2% absolute at 48 weeks on the 12 mg dose, and the pivotal Phase 3 TRIUMPH-1 trial (topline May 2026, full data ADA 2026) reported up to 28.3% absolute mean weight loss at 12 mg over 80 weeks, with 30.3% at 104 weeks in the BMI ≥35 subgroup.
As with any cross-trial comparison, the caveats are load-bearing: enicepatide's headline number is placebo-adjusted while retatrutide's are absolute, the trials differ in duration and stage (Phase 2 vs Phase 3), and the populations and dosing are not matched. On the strength of available data, retatrutide has the larger and more mature efficacy signal — it has cleared a pivotal Phase 3 endpoint, which enicepatide has not — but a direct efficacy ranking would require a head-to-head trial that does not exist.
Development Stage
Retatrutide is more advanced: its Phase 3 TRIUMPH-1 obesity trial met its primary endpoint (topline May 21, 2026), with full data at ADA 2026 and an FDA submission anticipated to follow. Enicepatide is in Phase 2, with Phase 3 and a multi-arm combination program (including a combination with the amylin analog petrelintide) planned to begin in 2026. Both remain investigational and not legally available outside of clinical trials.
Side Effect Profile
Both share the incretin-class gastrointestinal profile (nausea, vomiting, diarrhea, constipation), most pronounced during dose escalation. Retatrutide's glucagon agonism introduces additional considerations — most notably fasting-glucose monitoring, although overall glycemic control improved in trials because the GLP-1/GIP effects dominate. Enicepatide's safety is characterized only through Phase 2. The GLP-1 class boxed warning for thyroid C-cell tumors is anticipated to apply to both by class-labeling precedent.
Strategic Positioning
The two programs reflect different bets on how to push obesity efficacy further: retatrutide adds a third receptor (glucagon) to maximize magnitude, while enicepatide refines the dual-agonist approach through signalling design and is being developed as one component of a combination strategy with an amylin analog. Whether "more receptors" or "better-designed dual agonism plus amylin combinations" wins on the efficacy-tolerability tradeoff is an open question the next few years of trials will address.
Which Is Better For...?
The largest and most mature reported efficacy signal — retatrutide cleared a pivotal Phase 3 endpoint (TRIUMPH-1, up to 28.3% at 12 mg / 80 weeks) and is closer to a potential regulatory submission than enicepatide.
Interest in the triple-agonist mechanism specifically — the added glucagon-receptor energy-expenditure component is the differentiator for people following the highest-magnitude end of the obesity-pharmacotherapy pipeline.
Following dual-agonist refinement and combination strategy — enicepatide's biased-signalling design and its planned combination with the amylin analog petrelintide represent a different path to durable efficacy with potentially favorable tolerability.
People weighing the tolerability tradeoff of adding receptors — a dual agonist avoids the additional glucagon-related considerations of a triple agonist, though comparative tolerability has not been tested head-to-head.
Clinical-trial participants seeking the most-studied investigational option — retatrutide's larger Phase 3 dataset offers a more complete (though still pre-approval) risk-benefit picture than enicepatide's Phase 2 data.