Cagrilintide
Cagrilintide (long-acting amylin analogue) · Lipidated amylin analogue · ~4000 Da (acylated peptide)
Executive Summary
Cagrilintide is a long-acting amylin analogue (dual amylin/calcitonin receptor agonist) engineered for once-weekly subcutaneous dosing. The peer-reviewed evidence base supports one core claim with confidence: it reduces energy intake and produces clinically meaningful weight loss in humans. In the best-described monotherapy trial (a 26-week phase 2 dose-finding RCT, n=706), weekly cagrilintide produced ~6.0%–10.8% mean weight loss (dose-dependent) versus ~3.0% with placebo, with gastrointestinal adverse events common. The most dramatic results come from combination with semaglutide (CagriSema): in REDEFINE 1 (phase 3a; n=3417), CagriSema achieved ~20.4% mean weight loss at 68 weeks versus ~3.0% with placebo, with GI adverse events in ~79.6% of the active group. Cagrilintide is not FDA-approved; the FDA explicitly states it cannot be used in compounding and has not been found safe and effective for any condition. Any cagrilintide sold as a research peptide for self-use is outside regulated medicine.
Cagrilintide is a credible, satiety-pathway anti-obesity drug candidate with meaningful monotherapy weight loss and stronger effects when combined with semaglutide. The evidence is unusually trial-heavy for an unapproved compound. The limiting factor is not whether it works; it is regulatory status, long-term safety data, and the gap between trial conditions and unregulated self-use.
What Cagrilintide Is and What It Is Not
Cagrilintide is a stable, lipidated, long-acting analogue of the pancreatic hormone amylin, designed for once-weekly subcutaneous injection. Amylin is co-secreted with insulin and pharmacologically reduces meal size, appetite, and slows gastric emptying via central and peripheral pathways. At the receptor level, amylin receptors are heterodimers built from the calcitonin receptor (CTR) plus RAMP1/2/3, creating AMY receptor subtypes. Cryo-EM structural work has confirmed how cagrilintide engages both AMY receptors and CTR, supporting its classification as a dual amylin/calcitonin receptor agonist. The protracted exposure profile is plausibly driven by reversible albumin binding, a design strategy also used for other long-acting peptide drugs.
- It is not an FDA-approved drug for any indication. The FDA explicitly states cagrilintide has not been found safe and effective for any condition.
- It is not the same as CagriSema. CagriSema is a fixed combination of cagrilintide plus semaglutide; effects differ materially from cagrilintide alone.
- It is not a legal compounding ingredient. The FDA states cagrilintide cannot be used in compounding under federal law.
- It is not a GLP-1 receptor agonist. It works through the amylin/calcitonin receptor system, which is a distinct signalling pathway from GLP-1.
Mechanism of Action
Amylin receptor agonism and satiety signalling
Well-supported mechanistic basisCagrilintide activates AMY receptor subtypes (heterodimers of CTR + RAMP1/2/3), producing satiety signalling that reduces meal size and energy intake. Cryo-EM structural studies have mapped how cagrilintide engages these receptor complexes, providing molecular-level rationale for its appetite-suppressing effects. Animal studies in RAMP1/3 knockout mice confirm dependence on AMY receptor subtypes for the weight-lowering phenotype.
The mechanistic data justify why appetite falls; they do not prove downstream claims like fat-only loss, muscle sparing, or cardiovascular event reduction, which require human outcomes trials.
Long-acting pharmacokinetic design
Demonstrated in human PK studiesCagrilintide was engineered with lipidation and sequence modifications to overcome native amylin's short half-life and amyloid fibril formation tendency. Human PK data from a phase 1b trial show a half-life of ~159–195 hours (roughly 6.5–8 days), with median tmax of ~24–72 hours, supporting once-weekly dosing. Exposure increased with dose and did not meaningfully alter semaglutide exposure when co-administered.
The long half-life supports weekly dosing convenience but also implies that adverse effects and dosing errors could persist for days. This is particularly relevant outside supervised clinical settings.
Energy expenditure preservation (combination only)
Preclinical signal, not proven in humansA preclinical study in rats tested CagriSema and found weight loss driven primarily by reduced energy intake, but with an additional effect described as blunting metabolic adaptation (relative preservation of energy expenditure compared with pair-fed controls).
This is a combination-product finding in rodents. Translation to humans is uncertain, and it does not apply to cagrilintide monotherapy. The metabolic reset narrative common on social media is not supported by human evidence.
Animal Evidence Map
The preclinical literature contains many positive findings, summarised below with stated limitations.
| Domain | Species | Dose | Outcome | Limitation |
|---|---|---|---|---|
| Weight loss / receptor dependency | Mouse (high-fat diet; RAMP1/3 KO) | 3 nmol/kg subcutaneous daily (3 weeks) | Weight loss and early food-intake reduction in wild-type mice; effects altered in RAMP1/3 knockout animals, supporting AMY receptor dependence | Rodent dosing and neurobiology do not map cleanly onto human chronic obesity; short duration. |
| Energy balance (CagriSema combination) | Rat | Combination regimen (details in paper) | Weight loss attributed mainly to reduced energy intake, with additional effect on energy expenditure vs pair-fed controls | Combination product, not cagrilintide alone; translation of energy-expenditure findings to humans is uncertain. |
Human Evidence
Every published human study for Cagrilintide is reviewed below.
Phase 2 dose-finding monotherapy RCT
26-week randomised, blinded phase 2 trial26 weeks only; lifestyle co-interventions; long-term outcomes unknown; not powered for rare adverse events.
Strong evidence that cagrilintide works for weight loss over 6 months. Not evidence of superiority to GLP-1s in long-term outcomes.Phase 1b cagrilintide + semaglutide combination
20-week phase 1b trialSmall cohorts; short duration; not powered for rare AEs. Exactly the kind of data inflated into guaranteed 15–20% loss claims online.
Legitimate early evidence for synergy, but small cohorts and short duration limit confidence.Phase 2 CagriSema in type 2 diabetes
32-week randomised phase 2 trialSmall sample; limited duration; HbA1c advantage of combo over semaglutide did not meet conventional significance thresholds; outcomes trial absent.
Glycaemic magic claim is overstated. Glycaemic control largely driven by semaglutide; cagrilintide adds weight loss.REDEFINE 1: Phase 3a in obesity without diabetes
68-week phase 3a randomised trialLong-term beyond 68 weeks, rare events, and durability still uncertain; full adherence vs real-world gaps matter. Cagrilintide monotherapy less potent than semaglutide at these doses.
Large, well-controlled trial confirms meaningful weight loss. CagriSema combination strongest; cagrilintide monotherapy meaningful but less potent than semaglutide.REDEFINE 2: Phase 3a in type 2 diabetes
68-week phase 3a randomised trialSame durability and rare-event limits as REDEFINE 1; background diabetes medications complicate comparisons; combination product results, not monotherapy.
Confirms CagriSema efficacy in diabetes population with strong weight and glycaemic outcomes.Hype vs Evidence
Common online claims compared against what the published evidence actually supports.
| Claim | Social Media Implies | Evidence Supports | Verdict |
|---|---|---|---|
| Cagrilintide alone causes ~20%+ weight loss | Monotherapy produces dramatic weight loss comparable to CagriSema | Cagrilintide monotherapy showed ~6%–10.8% mean loss at 26 weeks in phase 2; larger ~20% figures are from cagrilintide+semaglutide combination in phase 3. REDEFINE 1 showed ~11.5% for cagrilintide alone vs ~20.4% for CagriSema. |
Misleading (confuses monotherapy with combination)
|
| It's basically CagriSema in a vial | Buying cagrilintide alone gives you CagriSema results | CagriSema is a fixed combination regimen in trials; effects differ materially from cagrilintide alone. Weight loss is substantially greater with the combination. |
False framing
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| No nausea / easy to tolerate | Minimal side effects compared to GLP-1 drugs | GI adverse events are common across all trials: nausea up to ~47% in some dose groups (phase 2); 79.6% GI AEs in REDEFINE 1 active arm; 72.5% in REDEFINE 2. |
False
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| It resets metabolism and prevents weight rebound | Preserves energy expenditure; prevents metabolic adaptation | Rat data suggest blunting of metabolic adaptation for the combination product only; human translation is unproven, and this is not established for cagrilintide monotherapy. |
Overhyped (preclinical to clinical leap)
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| It improves diabetes directly / regenerates the pancreas | Direct diabetes treatment with regenerative properties | In T2D phase 2, cagrilintide alone reduced HbA1c modestly (−0.9pp); combination improved HbA1c more than cagrilintide and not clearly more than semaglutide in the primary comparison; no evidence of pancreatic regeneration. |
Overstated
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| It reduces heart attacks and strokes | Cardiovascular protection proven | Blood pressure and inflammation markers improve in combination trial analyses; hard cardiovascular outcomes require dedicated outcomes trials which are ongoing or have insufficient publicly conclusive data. |
Not demonstrated
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| Compounded cagrilintide is a normal, legal option | Available through standard compounding like other peptides | FDA states cagrilintide cannot be used in compounding and is not an FDA-approved active ingredient; FDA has issued warning letters to vendors marketing such products for human use. |
False and high-risk
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Evidence Strength Ratings
Each domain rated on a 0-5 scale based on quality and quantity of available evidence.
Safety, Side Effects & Regulatory Status
Human pharmacokinetics are best characterised from a phase 1b trial of cagrilintide co-administered with semaglutide. The reported half-life across doses is ~159–195 hours (roughly 6.5–8 days), with median tmax of ~24–72 hours. Exposure increased with dose and did not meaningfully alter semaglutide exposure. This supports practical weekly dosing but also implies that adverse effects and dosing errors (especially outside trials) could persist for days.
Across phase 1–3 studies, the dominant safety signal is gastrointestinal intolerance: nausea, vomiting, diarrhoea, constipation, and abdominal discomfort, typically described as mostly mild-to-moderate and often concentrated around dose escalation. In the phase 2 monotherapy trial, nausea was reported in up to ~47% in some dose groups. In phase 3, GI AEs were very common: ~79.6% (REDEFINE 1) and ~72.5% (REDEFINE 2). Discontinuation due to adverse events was ~6% vs 3.7% (active vs placebo) in REDEFINE 1 and ~8.4% vs 3% in REDEFINE 2. Rare and long-term harms remain uncertain because there is no post-approval pharmacovigilance base.
Cagrilintide is not an FDA-approved active ingredient. The FDA explicitly states it has not been found safe and effective for any condition and cannot be used in compounding under federal law. The FDA has issued warning letters to vendors marketing cagrilintide products for human use.
View Official Source →The FDA has taken enforcement action against companies marketing unapproved cagrilintide-containing products, including warning letters citing violations of federal law regarding unapproved new drugs.
View Official Source →The EMA has published paediatric investigation plan decisions for the cagrilintide/semaglutide combination, indicating regulatory engagement in development but this is not a marketing authorisation.
View Official Source →What We Still Don't Know
- No post-marketing safety data exist because cagrilintide is not approved anywhere. Rare adverse events cannot be characterised from trial data alone.
- Long-term weight maintenance beyond 68 weeks is not established; durability of weight loss after discontinuation is unknown.
- Cardiovascular outcomes data (hard events like heart attacks and strokes) are absent; development programmes exist but have not reported conclusive results.
- The contribution of cagrilintide versus semaglutide in the CagriSema combination for glycaemic control remains uncertain; the HbA1c advantage did not reach conventional significance in the phase 2 comparison.
- Energy expenditure preservation (metabolic reset) is a preclinical observation in rats for the combination product only; human relevance is unproven.
- Quality, purity, and dosing accuracy of grey-market research peptide cagrilintide products are unknown and unregulated; the FDA has flagged this as a specific risk area.
References
All primary sources cited in this review. Links open in new tabs.
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Phase 2 dose-finding monotherapy trial in adults without diabetes26-week randomised, blinded phase 2 trial (n=706) of weekly cagrilintide 0.3–4.5 mg showing dose-dependent weight loss of ~6.0%–10.8% vs ~3.0% placebo
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Phase 1b cagrilintide + semaglutide PK and weight loss20-week phase 1b trial testing multiple cagrilintide doses with semaglutide 2.4 mg; half-life ~159–195 hours; combination weight loss ~15.7%–17.1%
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Phase 2 CagriSema vs components in type 2 diabetes32-week phase 2 RCT (n=92) comparing CagriSema 2.4/2.4 mg vs semaglutide vs cagrilintide in T2D; weight −15.6% vs −5.1% vs −8.1%
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REDEFINE 1: Phase 3a CagriSema in obesity without diabetes68-week phase 3a trial (n=3417); CagriSema ~20.4% weight loss vs ~3.0% placebo; GI AEs 79.6% vs 39.9%
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REDEFINE 2: Phase 3a CagriSema in type 2 diabetes68-week phase 3a trial (n=1206); CagriSema −13.7% weight loss vs −3.4% placebo; HbA1c ≤6.5% in 73.5% vs 15.9%
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Cryo-EM structure of cagrilintide–AMY receptor complexStructural study mapping cagrilintide engagement with amylin and calcitonin receptor complexes via cryo-electron microscopy
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RAMP1/3 knockout study: AMY receptor dependency for weight lossHigh-fat-diet mouse study showing cagrilintide weight loss depends on AMY receptor subtypes; effects altered in RAMP1/3 knockout animals
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CagriSema energy balance study in ratsPreclinical study showing CagriSema weight loss driven by reduced intake with additional energy expenditure preservation vs pair-fed controls
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Medicinal chemistry and design of cagrilintideDrug design publication describing sequence modifications, lipidation strategy, stability improvements, and reduced fibrillation propensity
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REDEFINE 1 cardiovascular risk factor analysisAnalysis of blood pressure and cardiovascular risk factor changes from REDEFINE 1 trial
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Systematic review / meta-analysis of cagrilintide trialsComprehensive analysis across cagrilintide clinical trial data
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Phase 2 monotherapy trial registry (NCT03856047)ClinicalTrials.gov registration for the 26-week phase 2 dose-finding monotherapy trial
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Phase 1b combination trial registry (NCT03600480)ClinicalTrials.gov registration for the phase 1b cagrilintide + semaglutide trial
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FDA warning: unapproved GLP-1-related productsFDA safety communication explicitly stating cagrilintide is not approved and cannot be used in compounding
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FDA warning letter to cagrilintide vendorFDA enforcement action against company marketing unapproved cagrilintide products for human use
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ADA press release on CagriSema weight loss resultsAmerican Diabetes Association summary reporting REDEFINE 1 comparator arm data including monotherapy results
View the compound profile for Cagrilintide including dosage forms, administration routes, and category information.
View Compound Profile →Frequently Asked Questions About Cagrilintide
Cagrilintide is a long-acting amylin analogue (dual amylin/calcitonin receptor agonist) designed for once-weekly subcutaneous injection. It works by activating amylin receptor subtypes to reduce appetite and energy intake. It is currently in clinical development and is not approved by the FDA or any major regulatory body for any indication.
In a 26-week phase 2 trial (n=706), cagrilintide monotherapy produced ~6.0%–10.8% mean weight loss depending on dose, versus ~3.0% with placebo. In the REDEFINE 1 phase 3 trial, cagrilintide alone achieved ~11.5% weight loss at 68 weeks. The larger ~20% figures often cited online come from the CagriSema combination (cagrilintide plus semaglutide), not cagrilintide alone.
No. As of 2026, cagrilintide is not approved by the FDA or any major regulatory body. The FDA explicitly states it has not been found safe and effective for any condition. Additionally, cagrilintide cannot be legally used in compounding under federal law, and the FDA has issued warning letters to vendors marketing cagrilintide products for human use.
The dominant side effects across clinical trials are gastrointestinal: nausea (up to ~47% in some dose groups), vomiting, diarrhoea, constipation, and abdominal discomfort. These are typically mild-to-moderate and concentrated around dose escalation. In phase 3 trials, GI adverse events occurred in ~72–80% of active treatment groups. Discontinuation due to adverse events was ~6–8% in phase 3 studies.
CagriSema is a fixed combination of cagrilintide (an amylin analogue) plus semaglutide (a GLP-1 receptor agonist) given as a once-weekly subcutaneous injection. In the REDEFINE 1 phase 3 trial, CagriSema achieved ~20.4% mean weight loss at 68 weeks. CagriSema is a combination product. Its results cannot be attributed to cagrilintide alone.
In the REDEFINE 1 trial, which included direct comparison arms, semaglutide alone achieved ~14.9% weight loss versus ~11.5% for cagrilintide alone at 68 weeks. The combination of both (CagriSema) achieved ~20.4%. Cagrilintide is meaningful as a weight loss agent but appears less potent than semaglutide at the tested doses. The two drugs work through different receptor systems (amylin vs GLP-1) and appear complementary.
Cagrilintide is sold by some online vendors as a research peptide, but this is outside regulated medicine. The FDA explicitly warns that cagrilintide cannot be used in compounding and has issued warning letters to companies marketing such products. Products sold outside regulated systems carry unknown quality, purity, and dosing accuracy risks.
There is no completed, publicly conclusive cardiovascular outcomes data for cagrilintide or CagriSema establishing that it reduces heart attacks or strokes. Blood pressure and some risk-factor improvements have been reported in trial analyses, but these are surrogate markers, not hard event outcomes. Dedicated cardiovascular outcomes trials are in development.
Reviewed by the Peptide Science Thailand Editorial Team.
Last reviewed: March 1, 2026