Eloralintide (LY3841136): What It Is, How It Works, Benefits, and Research Overview :root{--ink:#16202a;--muted:#5c6975;--line:#dce3e8;--panel:
Eloralintide (LY3841136): What It Is, How It Works, Benefits, and Research Overview
A comprehensive, evidence-graded review of eloralintide, a once-weekly investigational selective amylin-receptor agonist being developed by Eli Lilly for obesity and related metabolic disease.
What Is Eloralintide?
Eloralintide, also known as LY3841136, is a potent, long-acting, selective amylin-receptor agonist developed by Eli Lilly for obesity treatment.
Amylin is a pancreatic hormone co-secreted with insulin. It contributes to:
- Satiation and meal termination
- Fullness between meals
- Reduced food intake
- Postprandial glucagon regulation
- Transient slowing of gastric emptying
LY3841136
Long-acting synthetic amylin analogue
Amylin receptors
Once-weekly subcutaneous injection
About 14 days
No
🧬 Structure and Public Chemistry Information
What is publicly known
- Eloralintide is a synthetic analogue of human amylin.
- Its amino-acid chain has been modified to support once-weekly dosing.
- It was engineered to improve receptor selectivity, reduce immunogenicity risk, and improve pharmaceutical developability.
- It is more potent at amylin receptors than at the calcitonin receptor.
What is not publicly disclosed
| Complete amino-acid sequence | Not publicly disclosed in the primary clinical and preclinical publications reviewed |
|---|---|
| Molecular formula | Not publicly disclosed |
| Exact molecular weight | Not publicly disclosed |
| Disulfide pattern | Not publicly disclosed |
| Lipid or half-life extension chemistry | Not fully disclosed |
| Official CAS number | No authoritative public reference confirmed |
📅 Discovery Timeline and Development History
Early amylin research
Native amylin and pramlintide established amylin biology in appetite and glucose regulation.
Lilly discovery program
Lilly developed LY3841136 as a selective amylin-receptor agonist intended to improve weight-loss efficacy, gastrointestinal tolerability, and once-weekly exposure.
2022–2024: Phase 1 multiple-dose study
A 12-week study evaluated once-weekly doses up to 12 mg in adults with obesity or overweight.
June 2025: Early proof-of-concept data
Lilly presented phase 1 results showing up to 11.3% mean weight reduction over 12 weeks across dose groups.
November 2025: Phase 2 publication
A 48-week phase 2 trial reported dose-dependent weight reduction, including approximately 20.1% at the highest fixed dose.
December 2025: Phase 3 initiation
Lilly advanced eloralintide into late-stage obesity trials.
2026: Expanded phase 3 program
Studies began in adults with obesity with and without type 2 diabetes and in obesity-related knee osteoarthritis.
Current status
Eloralintide remains investigational and has not received FDA approval.
🧠 How Does Eloralintide Work?
1. Satiation
Eloralintide appears to help reduce meal size and terminate eating earlier.
2. Satiety
Its long exposure may prolong fullness between meals and reduce daily calorie intake.
3. Food reward
Amylin signaling can influence mesolimbic pathways involved in palatable-food motivation.
4. Glucagon regulation
Early clinical data showed an overall reduction in fasting glucagon, although without a consistently dose-related pattern.
5. Gastric effects
Higher doses produced a modest initial reduction in acetaminophen exposure after the first dose, but the effect returned toward baseline with repeated dosing, suggesting transient rather than persistent slowing of gastric emptying.
🎯 Amylin-Receptor Selectivity
Amylin receptor architecture
Amylin receptors are formed by the calcitonin receptor combined with one of three receptor activity-modifying proteins:
| Receptor complex | Components | Eloralintide relevance |
|---|---|---|
| AMY1 | CTR + RAMP1 | Reported preferential affinity and potency |
| AMY2 | CTR + RAMP2 | Amylin-receptor activity |
| AMY3 | CTR + RAMP3 | Lower relative affinity and potency than AMY1 in reported profiling |
| Calcitonin receptor | CTR without RAMP | Substantially lower potency than at amylin receptors |
Why selectivity may matter
Lilly researchers hypothesize that greater amylin-receptor selectivity and lower calcitonin-receptor activity may contribute to improved gastrointestinal tolerability relative to broader amylin/calcitonin receptor agonists.
Hypothesis, not final proof
Differences in half-life, absorption rate, receptor balance, dosing schedule, and study design may also contribute to tolerability.
Brain Pathways and Appetite Regulation
Area postrema
The area postrema is a major circulating-amylin sensor involved in satiation and nausea-related signaling.
Nucleus of the solitary tract
Brainstem pathways coordinate meal termination, autonomic function, and gastric responses.
Hypothalamus
Secondary pathways influence longer-term appetite and energy balance.
Reward circuitry
Amylin-family signaling can reduce food-seeking behavior and the reward value of highly palatable food.
Selective-receptor hypothesis
Preferential AMY1 signaling may help separate therapeutic satiety from excessive calcitonin-receptor-related adverse effects, but this remains under investigation.
Preclinical Research
Food intake
Eloralintide reduced food intake in diet-induced-obese rats.
Body weight
Repeated dosing produced dose-dependent weight reduction.
Body composition
Most lost weight was attributed to fat mass rather than lean mass in the reported rat studies.
Gastrointestinal tolerability model
At exposures producing similar weight loss, eloralintide produced less conditioned taste avoidance than cagrilintide in rats.
Species translation limitation
Rodent taste-avoidance models can help compare compounds but cannot establish human nausea or long-term tolerability.
Phase 1 Evidence
Study design
A randomized, placebo-controlled, participant- and investigator-blinded study enrolled 100 adults with obesity or overweight.
Doses
Participants received 1.2 mg, 3 mg, 6 mg, or 12 mg once weekly for 12 weeks without gradual titration.
Weight reduction
Mean body-weight reduction across dose groups ranged from approximately 2.6% to 11.3% at week 12.
Common adverse events
- Decreased appetite
- Headache
- Fatigue
- Diarrhea
- Nausea
- Vomiting
- Injection-site reactions
Gastrointestinal profile
Nausea and vomiting occurred mainly at higher doses and were less frequent than often reported with broader amylin or incretin therapies in indirect comparisons.
Phase 2 Obesity Evidence
Trial design
The 48-week randomized, double-blind, placebo-controlled study enrolled 263 adults with obesity or overweight and at least one weight-related condition, without type 2 diabetes.
Study groups
- Placebo
- 1 mg fixed dose
- 3 mg fixed dose
- 6 mg fixed dose
- 9 mg fixed dose
- 6-to-9 mg escalation
- 3-to-6-to-9 mg escalation
| Phase 2 finding | Reported result |
|---|---|
| 1 mg fixed dose | Approximately 9.5% mean weight reduction |
| Highest 9 mg fixed dose | Approximately 20.1% mean weight reduction |
| Placebo | Approximately 0.2 kg weight reduction |
| Study duration | 48 weeks |
Metabolic effects
Improvements were reported in waist circumference, blood pressure, lipid measures, glycemic measures, and inflammatory biomarkers.
Plateau
Weight loss had not clearly plateaued at 48 weeks in higher-dose groups.
Tolerability
The most common events were mild to moderate gastrointestinal symptoms and fatigue. Slower dose escalation reduced adverse-event incidence.
Phase 3 Development
Obesity without type 2 diabetes
NCT07321886 is evaluating eloralintide versus placebo in approximately 1,980 adults over about 75 weeks, with an extension for participants with prediabetes.
Obesity with type 2 diabetes
NCT07282600 is evaluating efficacy and safety in approximately 1,035 adults with obesity or overweight and type 2 diabetes.
Knee osteoarthritis
A phase 3 master protocol is studying adults with obesity and painful knee osteoarthritis.
Long-term outcomes
Phase 3 trials are needed to confirm durability, cardiovascular and gallbladder risk, rare adverse events, lean-mass effects, and weight maintenance.
Combination Research
Eloralintide plus tirzepatide
Lilly is evaluating eloralintide alone and together with tirzepatide to determine whether amylin and GIP/GLP-1 mechanisms provide additive weight loss.
Potential advantages
- Complementary appetite pathways
- Greater total weight reduction
- Potentially improved fat-mass selectivity
- Possibility of lower doses of each component
Potential disadvantages
- Additive gastrointestinal effects
- Greater complexity of dose escalation
- More difficult attribution of adverse events
- Unknown long-term risk
Macupatide combination research
A separate 2026 study is evaluating eloralintide with macupatide, another investigational metabolic compound.
Body Composition and Metabolic Effects
Fat mass
Preclinical studies found weight loss was primarily driven by fat-mass reduction.
Lean mass
Preservation of lean tissue is a major research question, but definitive long-term human body-composition data remain limited.
Waist circumference
Phase 2 reductions suggest meaningful central-adiposity improvement.
Blood pressure and lipids
Favorable phase 2 changes were reported, but cardiovascular-outcome benefit has not been established.
Inflammatory markers
Markers of systemic inflammation improved in the phase 2 program, likely in part because of fat loss.
Gastric Emptying and Glucagon Effects
Transient gastric effect
Acetaminophen testing suggested modest slowing after the first dose at higher doses, followed by return toward baseline with repeated dosing.
Potential tolerability benefit
Less persistent gastric slowing may reduce nausea, reflux, medication-absorption concerns, or aspiration risk compared with some other appetite therapies, but this requires confirmation.
Fasting glucagon
Fasting glucagon decreased overall, although the change was variable and not clearly dose dependent.
Side Effects and Safety Considerations
Most common reported effects
- Reduced appetite
- Fatigue
- Headache
- Nausea
- Diarrhea
- Vomiting
- Injection-site reactions
Mood-related events
Mood-related events were observed in early research and require continued surveillance in larger studies.
Potential amylin-class concerns
- Excessive appetite suppression
- Delayed gastric emptying
- Dehydration
- Hypoglycemia when combined with insulin
- Changes in oral medication absorption
Long-term uncertainty
Long-term cardiovascular, pancreatic, gallbladder, psychiatric, immunogenicity, and weight-regain risks remain unknown.
Pharmacokinetics and Weekly Dosing
Long half-life
Eloralintide has an approximate half-life of two weeks.
Slow absorption
A relatively slow time to maximum concentration produces flat weekly exposure.
Low peak-to-trough fluctuation
Steady-state peak-to-trough ratios were approximately 1.28 to 1.38 in phase 1.
Potential tolerability relevance
Flat exposure may reduce sharp concentration peaks that can trigger nausea or other adverse effects.
Accumulation
A two-week half-life means drug accumulation and delayed washout must be considered during titration and adverse-event management.
Regulatory Status
United States
Eloralintide is not FDA approved.
Clinical development
Phase 3 trials began in late 2025 and continue through 2026.
No approved brand name
No commercial brand, approved dosing schedule, or approved prescribing information exists.
Research-market claims
A vendor product cannot be assumed equivalent to Lilly’s clinical molecule unless the complete proprietary identity and pharmaceutical manufacturing controls are independently established.
🧪 Laboratory Testing Methods
| Method | Purpose | Important limitation |
|---|---|---|
| RP-HPLC / UPLC | Separates intact drug substance from deletion peptides, oxidation products, aggregates, and process impurities. | Cannot prove eloralintide identity without a disclosed reference structure. |
| LC-HRMS | Confirms intact mass relative to an authentic reference standard. | No public reference mass is currently available for independent comparison. |
| MS/MS peptide mapping | Confirms sequence and modification sites. | Requires access to the proprietary sequence and qualified standard. |
| Reduced/nonreduced mapping | Confirms disulfide architecture if present. | Public disulfide details are not disclosed. |
| Amino-acid analysis | Confirms composition and net peptide content. | Cannot prove sequence or identity by itself. |
| Chiral amino-acid analysis | Detects epimers and D-amino-acid impurities. | Requires known expected stereochemistry. |
| Modification-site analysis | Confirms any lipid, linker, or half-life extension chemistry. | The public modification architecture is incomplete. |
| SEC-HPLC | Measures aggregates and high-molecular-weight species. | Small oligomers may require orthogonal testing. |
| DLS and particle analysis | Assesses self-association and particle formation. | Formulation conditions strongly affect results. |
| Net peptide-content assay | Measures actual active mass. | Requires authentic calibrator and salt correction. |
| AMY1 cAMP assay | Measures preferred amylin-receptor activity. | Does not alone establish selectivity. |
| AMY2 and AMY3 assays | Measures broader amylin-receptor activity. | Receptor-expression differences alter potency values. |
| Calcitonin-receptor assay | Confirms lower CTR potency relative to amylin receptors. | Critical for the claimed selectivity profile. |
| Selectivity-ratio analysis | Compares AMY1, AMY3, and CTR potency. | Requires standardized cell systems. |
| Albumin-binding assay | Evaluates long-acting exposure if lipidated. | The public half-life extension mechanism is not fully disclosed. |
| Plasma stability | Measures proteolysis and chemical degradation. | Species and matrix differences matter. |
| Immunogenicity assay | Measures anti-drug antibodies in clinical development. | Requires validated human samples and drug-tolerance controls. |
| Sterility and endotoxin | Required for finished injectable products. | Raw-peptide purity cannot establish injectable safety. |
| Particulate matter | Measures visible and subvisible particles. | Requires final formulation testing. |
| Stability-indicating assay | Tracks oxidation, deamidation, aggregation, hydrolysis, and potency loss. | Requires full proprietary impurity knowledge. |
📄 How to Interpret an Eloralintide COA
- Do not accept an unsupported public sequence: The complete authentic sequence has not been publicly disclosed in the primary literature reviewed.
- Require an authentic Lilly-linked or legally licensed reference standard: Without one, identity cannot be conclusively established.
- Require complete structural disclosure: Sequence, nonstandard residues, disulfides, amidation, linker, lipidation, and counterion.
- Confirm intact mass and MS/MS mapping against the disclosed reference.
- Confirm stereochemistry: Epimers can share the same nominal mass.
- Measure aggregates, deletion peptides, oxidation, deamidation, hydrolysis, and process impurities.
- Report net peptide content rather than HPLC area alone.
- Test AMY1, AMY2, AMY3, and calcitonin-receptor potency separately.
- Confirm the claimed receptor-selectivity ratio.
- For injectable products, require sterility, endotoxin, particles, fill accuracy, container closure, and stability.
- Do not infer clinical equivalence: A generic COA cannot prove equivalence to Lilly’s clinical-trial drug.
📊 Eloralintide vs Cagrilintide vs Pramlintide vs Petrelintide
| Feature | Eloralintide | Cagrilintide | Pramlintide | Petrelintide |
|---|---|---|---|---|
| Main target | Selective amylin receptors | Amylin and calcitonin receptors | Amylin receptors | Long-acting amylin analogue |
| Dosing concept | Weekly | Weekly | With meals | Weekly |
| Public sequence | Not disclosed | Publicly described | Publicly described | Limited public chemistry |
| FDA approved? | No | No | Yes, diabetes adjunct | No |
Eloralintide vs GLP-1 and GIP/GLP-1 Therapies
| Feature | Eloralintide | Semaglutide | Tirzepatide |
|---|---|---|---|
| Primary receptors | Amylin receptors | GLP-1R | GIPR + GLP-1R |
| Primary appetite mechanism | Satiation and fullness | Appetite and reward suppression | Dual incretin appetite and metabolic signaling |
| Route | Weekly injection | Weekly injection | Weekly injection |
| FDA approved? | No | Yes, specific products | Yes, specific products |
Eloralintide vs Eloralintide + Tirzepatide
| Attribute | Eloralintide alone | Combination |
|---|---|---|
| Targets | Amylin receptors | Amylin + GIP + GLP-1 pathways |
| Potential benefit | Alternative to incretin therapy | Greater additive weight loss |
| Main concern | Unknown long-term safety | Additive GI and metabolic effects |
| Status | Phase 3 | Phase 2 |
Eloralintide Raw Material vs Clinical-Trial Drug Product
| Quality attribute | Raw material | Clinical drug product |
|---|---|---|
| Identity | Requires proprietary reference | Sponsor-controlled identity |
| Potency | Full receptor panel required | Validated release specifications |
| Microbiology | Bioburden as applicable | Sterility, endotoxin, particles |
| Exposure | Not established by COA | Supported by clinical PK |
| Clinical equivalence | Cannot be established independently without full disclosure | Defined by sponsor manufacturing and trials |
🖼️ Original Diagram Specifications
Diagram 1: Public versus proprietary identity
Show a generic modified amylin peptide silhouette with labels for known features and question marks for undisclosed sequence and modification chemistry.
Diagram 2: Selective receptor mechanism
Show strong AMY1 signaling, lower AMY3 signaling, and much lower calcitonin-receptor activity.
Diagram 3: Appetite pathway
Show area postrema, brainstem, hypothalamus, reward system, reduced meal size, and prolonged fullness.
Diagram 4: Phase 1 and phase 2 results
Show up to 11.3% loss at 12 weeks and 20.1% at 48 weeks.
Diagram 5: Pharmacokinetic profile
Show slow absorption, approximately 14-day half-life, and flat once-weekly exposure.
Diagram 6: Eloralintide versus cagrilintide
Compare selective amylin-receptor activity with broader amylin/calcitonin-receptor activation.
Diagram 7: COA verification workflow
Show proprietary reference standard, sequence disclosure, HRMS, MS/MS, receptor-selectivity panel, aggregation, sterility, and stability.
❓ Frequently Asked Questions
Is eloralintide a peptide?
Yes. It is a synthetic long-acting analogue of human amylin.
What is its development code?
LY3841136.
What is its exact sequence?
The complete authentic sequence has not been publicly disclosed in the primary sources reviewed.
What is its molecular formula?
No authoritative public molecular formula has been confirmed.
What is its molecular weight?
No authoritative public molecular weight has been confirmed.
Is eloralintide FDA approved?
No.
How much weight loss did phase 2 report?
Up to approximately 20.1% at 48 weeks at the highest fixed dose.
How much weight loss occurred in phase 1?
Up to approximately 11.3% at 12 weeks across evaluated dose groups.
What receptors does it activate?
It is more potent at amylin receptors than at the calcitonin receptor, with reported preferential activity at AMY1.
How is it administered in trials?
Once-weekly subcutaneous injection.
What is its half-life?
Approximately two weeks.
What are the most common side effects?
Reduced appetite, fatigue, headache, nausea, diarrhea, vomiting, and injection-site reactions.
How is it different from cagrilintide?
Eloralintide is designed to be more selective for amylin receptors and less active at the calcitonin receptor.
Can a vendor prove eloralintide identity with HPLC?
No. HPLC purity alone cannot prove identity, especially when the authentic sequence and modifications are not publicly disclosed.
Final Thoughts
Eloralintide is an investigational, once-weekly selective amylin-receptor agonist with unusually strong early weight-loss data. Phase 1 produced up to 11.3% mean weight reduction at 12 weeks, while phase 2 reported approximately 20.1% at the highest fixed dose over 48 weeks.
Its main scientific differentiator is receptor selectivity. Lilly researchers report greater potency at amylin receptors, especially AMY1, than at the calcitonin receptor, together with a slow absorption profile and an approximately two-week half-life. These characteristics may contribute to strong efficacy with less persistent gastrointestinal intolerance, although this remains to be confirmed in phase 3.
Because Lilly has not publicly disclosed the full reference sequence, molecular formula, molecular weight, or modification architecture, independent authentication is unusually difficult. A credible COA would require access to an authentic proprietary reference standard and complete structural disclosure, followed by sequence mapping, stereochemical analysis, impurity characterization, receptor-selectivity testing, aggregation testing, and finished-injectable quality controls.
📚 References
- Billings LK, et al. Eloralintide, a selective amylin receptor agonist for the treatment of obesity: a 48-week phase 2 trial. Lancet. 2025.
- Briere DA, et al. Eloralintide (LY3841136), a novel amylin receptor agonist for the treatment of obesity: from discovery to clinical proof of concept. Molecular Metabolism. 2025.
- Bhattachar S, et al. Eloralintide, a selective, long-acting amylin receptor agonist for treatment of obesity: Phase 1 proof of concept. Diabetes, Obesity and Metabolism. 2026.
- Eli Lilly and Company. What to know about eloralintide. November 2025.
- Eli Lilly and Company. Eloralintide demonstrated meaningful weight loss in phase 2. November 6, 2025.
- ClinicalTrials.gov. NCT06230523, phase 2 eloralintide obesity trial.
- ClinicalTrials.gov. NCT07321886, phase 3 obesity trial without type 2 diabetes.
- ClinicalTrials.gov. NCT07282600, phase 3 obesity trial with type 2 diabetes.
- ClinicalTrials.gov. NCT07353931, obesity and knee osteoarthritis studies.
- ClinicalTrials.gov. NCT06916065, eloralintide plus tirzepatide study.
- ClinicalTrials.gov. NCT07215559, macupatide and eloralintide combination study.
- Briere DA, et al. Eloralintide reduced food intake and body weight primarily through fat-mass loss in obese rats. Molecular Metabolism. 2025.
- Bhattachar S, et al. Phase 1 pharmacokinetic and tolerability analysis of eloralintide. Diabetes. 2025.
- Boyle CN, Zheng Y, Lutz TA. Mediators of amylin action in metabolic control. Journal of Clinical Medicine. 2022.
- Mathiesen DS, et al. Amylin and calcitonin as therapeutic strategies for body weight and liver fat. Frontiers in Endocrinology. 2020.
- Hay DL, et al. Amylin receptors: molecular composition and pharmacology. Pharmacological Reviews.
- Poyner DR, et al. International Union of Pharmacology recommendations for calcitonin-family receptors. Pharmacological Reviews.
- Lutz TA. The role of amylin in the control of energy homeostasis. American Journal of Physiology.
- Mietlicki-Baase EG. Amylin-mediated control of energy balance. Physiology & Behavior.
- Hayes MR, et al. Amylin and energy balance: brainstem and reward pathways. Endocrinology.
- Roth JD, et al. Amylin receptor agonism and body-weight regulation. Endocrinology.
- Young AA. Amylin’s physiology and role in diabetes. Current Opinion in Endocrinology.
- Aronne L, et al. Progressive reduction in body weight after pramlintide treatment. Journal of Clinical Endocrinology and Metabolism. 2007.
- Smith SR, et al. Sustained weight loss with pramlintide. Diabetes Care. 2008.
- Lau DCW, et al. Once-weekly cagrilintide for weight management. Lancet. 2021.
- Garvey WT, et al. Cagrilintide and semaglutide in adults with obesity. New England Journal of Medicine. 2025.
- Frias JP, et al. Cagrilintide plus semaglutide in type 2 diabetes. Lancet. 2023.
- Drucker DJ. Mechanisms of action and therapeutic application of GLP-1. Cell Metabolism.
- Müller TD, et al. GLP-1 molecular physiology and therapeutic applications. Nature Reviews Drug Discovery.
- Jastreboff AM, et al. Tirzepatide once weekly for obesity. New England Journal of Medicine.
- Wilding JPH, et al. Semaglutide in adults with overweight or obesity. New England Journal of Medicine.
- Heymsfield SB, Wadden TA. Mechanisms and management of obesity. New England Journal of Medicine.
- Morton GJ, et al. Neurobiology of food intake. Nature Reviews Neuroscience.
- Kenny PJ. Reward mechanisms in obesity. Neuron.
- International Council for Harmonisation. ICH Q1A(R2): Stability Testing.
- International Council for Harmonisation. ICH Q2(R2): Validation of Analytical Procedures.
- International Council for Harmonisation. ICH Q3A and Q3B: Impurities.
- International Council for Harmonisation. ICH Q3C: Residual Solvents.
- International Council for Harmonisation. ICH Q6B: Specifications for Biotechnological Products.
- International Council for Harmonisation. ICH M10: Bioanalytical Method Validation.
- United States Pharmacopeia General Chapter <621>: Chromatography.
- United States Pharmacopeia General Chapter <71>: Sterility Tests.
- United States Pharmacopeia General Chapter <85>: Bacterial Endotoxins Test.
- United States Pharmacopeia General Chapter <788>: Particulate Matter in Injections.
Identity limitations, receptor pharmacology, phase 1 and phase 2 findings, phase 3 development, safety, pharmacokinetics, and analytical recommendations were reviewed in July 2026.