Eloralintide Research, Specifications & Scientific Information

Introduction

Eloralintide is an amylin analogue, and the argument for it is selectivity rather than potency.

Amylin's receptors are not free-standing proteins. They are the calcitonin receptor in complex with receptor activity-modifying proteins, and the different complexes — AMY1R, AMY3R — behave differently from each other and from the bare calcitonin receptor. Existing amylin analogues activate all of them. The hypothesis behind eloralintide is that some of what makes a non-selective amylin analogue unpleasant comes from the receptors it hits incidentally, and that a molecule confined to the amylin 1 receptor would behave differently.

That hypothesis has been tested in cells, in rats, and now in a 48-week randomised trial in people ^{[1, 2]}. What the published record does not yet contain is a phase 3 result or a head-to-head trial against a non-selective comparator, and this page says so rather than implying otherwise.

This page is a reference record. It sets out what has been published about eloralintide's structure, its receptor pharmacology, and the preclinical and clinical literature, with every source resolved against PubMed, Crossref or ClinicalTrials.gov at the time the page was built. It describes research. It does not describe use in people or animals, and it carries no guidance of any kind on handling the material.

What Is Eloralintide?

Eloralintide is an investigational synthetic peptide analogue of amylin, developed by Eli Lilly and Company under the code LY3841136 ^[1]. It is not an approved medicine in the United States and has not been approved by the U.S. Food and Drug Administration for any indication.

It sits in a different peptide family from most of the compounds around it in this category. The GLP-1, GIP and glucagon receptor agonists belong to the glucagon–secretin superfamily; amylin belongs to the calcitonin family, and its receptors are built from the calcitonin receptor plus accessory proteins. An amylin analogue is not an incretin analogue, and the two are not variations on a theme.

Functionally, eloralintide is described as an amylin 1 receptor-selective agonist — an agonist that is deliberately not equipotent across the receptor family it belongs to ^[1].

Eloralintide Specifications

The FDA/NCATS Global Substance Registration System records eloralintide under UNII 73G3354J8W as a substance with two subunits: the 36-residue chain written above, and a single glutamic acid residue recorded separately. The letter X in the main chain is the register's placeholder for a residue with no single-letter representation. The two cysteines at positions 1 and 6 of that string correspond to the disulfide-bridged loop that defines the amylin family — human amylin carries the same bridge — and a linear reading of the sequence therefore misses the cyclic structure entirely. The register also carries structural modifications for this substance, and its own calculated mass for the recorded backbone is approximately 3547 g/mol against the approximately 4526 g/mol carried by PubChem CID 175663130 for the complete molecule; the difference of roughly 980 daltons is the modification chemistry, consistent with the reported once-weekly pharmacokinetics. Any figure on this page is a reference value: the certificate of analysis supplied with a laboratory order is the record for a given lot.

Values that a public register does not carry are shown as not publicly characterised rather than estimated. Identifiers are reference values; the certificate of analysis supplied with a laboratory order is the record for a given lot.

How Does Eloralintide Work?

Amylin is co-secreted with insulin from pancreatic beta cells. Its signalling reaches hindbrain circuits that participate in the regulation of food intake — a different route from the incretin receptors, which is why amylin analogues and GLP-1 receptor agonists are studied both separately and together.

The receptor architecture is what makes selectivity possible at all. The calcitonin receptor alone responds to calcitonin. When it associates with receptor activity-modifying protein 1 it becomes AMY1R; with RAMP3, AMY3R. The same receptor protein therefore presents several different pharmacologies depending on what it is bound to, and a ligand can in principle discriminate between them.

The design claim for eloralintide is that discriminating in favour of AMY1R changes the tolerability profile rather than the mechanism — that activity at the other complexes contributes to aversive signalling without contributing proportionally to the effect being sought. That claim is testable in rodents and has been tested; whether it holds in people is a question the published human trials describe but do not settle, since none of them includes a non-selective comparator arm.

Eloralintide Mechanism of Action

In vitro research

The receptor characterisation was performed in cell lines expressing rat or human amylin 1 receptor, amylin 3 receptor, or calcitonin receptor individually — the arrangement that makes a selectivity claim measurable rather than inferred.

At the human receptors, eloralintide preferentially activated AMY1R: 12-fold over the calcitonin receptor and 11-fold over AMY3R ^[1].

At the rat receptors, the pattern was different. Both amylin receptors were activated more potently than the calcitonin receptor, without the AMY1R-over-AMY3R preference seen at the human receptors ^[1].

That species difference deserves more attention than it usually gets, because the behavioural evidence for the selectivity hypothesis comes from rats — an animal in which the compound is not, by this measurement, AMY1R-selective in the way it is at human receptors. The rodent finding described in the preclinical section below is therefore evidence that eloralintide differs behaviourally from a non-selective comparator; it is not, on its own, evidence that AMY1R selectivity is the reason.

Analytical characterisation of supplied material is a separate exercise from receptor pharmacology and relies on liquid chromatography with mass spectrometric detection against a reference standard rather than on any biological assay.

What Is Eloralintide Being Researched For?

Registered clinical research on eloralintide has covered:

• Obesity and overweight — a phase 1 single-ascending trial, a 12-week multiple-ascending trial, and a 48-week phase 2 trial, all reported ^{[1, 3, 2]}.
• Combination with an incretin receptor agonist — a completed phase 1 trial of eloralintide alone and with tirzepatide, not reported in the sources cited here ^[6].
• A respiratory disorder in the context of obesity, and osteoarthritis knee pain in the context of obesity — registered phase 3 trials, recruiting, with no results published ^{[8, 7]}.

Each of those is research into a pharmaceutical product candidate, conducted by its sponsor under a registered protocol. None of it is research into, or evidence about, research-grade material supplied for laboratory use.

Human Research on Eloralintide

Human clinical research

Results from pharmaceutical clinical trials describe the investigational material and populations used in those studies and should not be interpreted as establishing the effects of research-grade materials offered for laboratory use.

Phase 2 — 48 weeks in obesity or overweight

Population. 263 participants from 46 research centres in the United States, aged 18–75, with a body-mass index of 30 kg/m² or higher, or 27 kg/m² or higher with at least one weight-related comorbidity, and without type 2 diabetes. Mean age 49.0 years, mean body mass 109.1 kg, mean body-mass index 39.1 kg/m²; 78% female and 78% White ^{[2, 5]}.

Endpoint and duration. Primary endpoint the percent change in body mass from baseline after 48 weeks. Randomised 2:1:1:1:2:1:2 to placebo, or eloralintide at 1, 3, 6 or 9 mg once weekly, or escalation regimens of 6–9 mg or 3–9 mg ^[2].

Result. Mean percent change in body mass at 48 weeks on the efficacy estimand was −9% at 1 mg (95% CI −12.6 to −6.3), −12% at 3 mg (−14.9 to −9.8), −18% at 6 mg (−20.7 to −14.5), −20% at 9 mg (−22.7 to −17.5), −20% on the 6–9 mg escalation (−22.7 to −17.0) and −16% on the 3–9 mg escalation (−18.6 to −14.1), against −0.4% (−2.2 to 1.4) for placebo ^[2].

Adverse events. Nausea was reported by 11% (1 mg), 13% (3 mg), 64% (6 mg), 33% (9 mg), 54% (6–9 mg) and 25% (3–9 mg) of participants against 14% on placebo. Fatigue was reported by 0%, 13%, 29%, 43%, 46% and 21% against 12% on placebo ^[2].

Limitations. The adverse event figures do not follow the amount administered in an orderly way — 64% nausea at 6 mg against 33% at 9 mg — which in arms of 24 to 54 participants is what small numbers look like, and which should caution against reading any single percentage as a property of a regimen. Seventy-eight percent of participants were female and 78% were White. Phase 2, 48 weeks, with an anthropometric primary endpoint and no active comparator, so the trial does not test the selectivity hypothesis that motivates the compound.

Phase 1 — 12-week multiple-ascending study

Population. 100 participants with obesity or overweight at three centres in the United States, enrolled between March 2022 and January 2024. Mean age 44 years, 29% female, mean body-mass index 32.6 kg/m² ^[3].

Endpoint and duration. Safety, tolerability, pharmacokinetics and pharmacodynamics over 12 weeks of once-weekly subcutaneous administration without escalation, across five multiple-ascending cohorts, randomised against placebo ^[3].

Result. At week 12, exposure and maximum concentration were proportional to the amount administered, with ratios of amount-normalised geometric means of 1.1 and 1.0. Least-squares mean percent reduction in body mass across the groups ranged from 2.6% to 11.3% ^[3].

Adverse events. The most common treatment-emergent events were decreased appetite (19% of participants), headache (12%), fatigue (11%) and COVID-19 (11%). Gastrointestinal events were infrequent: diarrhoea 10%, nausea 8%, vomiting 4%. Most events were mild. There were no deaths, and one serious adverse event, in the 6 mg cohort, unrelated to the compound ^[3].

Limitations. A phase 1 study of 100 participants over 12 weeks, administered without escalation, and not designed to measure efficacy. The gastrointestinal rates here are much lower than those reported in the 48-week phase 2 trial above, which is the expected consequence of shorter exposure at lower amounts rather than a contradiction.

Phase 1 — single-ascending study in healthy participants

Population. 48 healthy participants with a mean body-mass index of 27.5 kg/m², within a randomised, placebo-controlled, participant- and investigator-blinded trial ^{[1, 4]}.

Endpoint and duration. Safety and tolerability of single administrations across a range from 0.04 to 12 mg ^[1].

Result. Nine participants in the eloralintide cohorts reported 16 adverse events, 15 of them mild. Two participants reported four gastrointestinal events, including one moderate vomiting event. In the cohorts receiving single administrations of 4 or 12 mg, mean percent change in body mass from baseline at week 4 was −2.5% (p < 0.01) and −4.4% (p < 0.001) against +0.6% for placebo. The pharmacokinetic profile was reported as supporting once-weekly administration ^[1].

Limitations. Forty-eight healthy participants receiving a single administration each. A four-week anthropometric change after one administration is a pharmacodynamic observation in a safety study, not an efficacy result.

Preclinical Research on Eloralintide

Animal research

The rodent work is where the selectivity hypothesis is actually tested, and the test is behavioural rather than biochemical.

Conditioned taste avoidance is the standard rodent assay for whether a compound produces an aversive internal state: an animal that associates a novel flavour with feeling unwell subsequently avoids it. In lean rats, eloralintide induced significantly less conditioned taste avoidance than cagrilintide, described in the same paper as a non-selective amylin receptor agonist, p < 0.05 ^[1].

In diet-induced obese rats, eloralintide reduced food intake and lowered body mass in proportion to the amount administered, with the reduction reported as primarily attributable to fat mass rather than to other tissue ^[1].

Pharmacokinetics were characterised in both rats and monkeys and reported as favourable, which is the basis on which a once-weekly human schedule was proposed ^[1].

Two limits on the central result. As noted in the mechanism section above, eloralintide's measured selectivity at rat receptors is not the same as its selectivity at human receptors, so a behavioural difference in rats does not by itself attribute that difference to AMY1R selectivity. And conditioned taste avoidance in a rat is a model of aversion, not a measurement of nausea in a person; the two have been correlated across compounds often enough to be informative and not often enough to be predictive.

Findings described in this section were observed in animals. Nothing in them establishes anything about humans.

Current Research Status

Status as of September 22, 2026. This block is rendered from maintained fields, not from prose, so it cannot go stale in one place and stay current in another.

Eloralintide vs Related Compounds

The distinctions between eloralintide and the compounds it is usually set beside are which receptor family each engages and how selectively, and nothing else is stated here.

Receptor family

Eloralintide and cagrilintide act at the amylin receptors — complexes of the calcitonin receptor with receptor activity-modifying proteins. Semaglutide, tirzepatide and retatrutide act at incretin and glucagon-family receptors. These are separate receptor families, not variants of one.

Selectivity within the family

Eloralintide is reported as 12-fold selective for human AMY1R over the calcitonin receptor and 11-fold over AMY3R ^[1]. Cagrilintide is described in the same paper as non-selective. No clinical trial has compared the two directly.

Combination

CagriSema pairs an amylin analogue with a GLP-1 receptor agonist as two separate peptides. A registered phase 1 trial has examined eloralintide with tirzepatide ^[6], with no published result.

Regulatory position

Eloralintide, cagrilintide, retatrutide and CagriSema are investigational. Semaglutide and tirzepatide are active ingredients of approved pharmaceutical products in the United States. Approval is specific to a finished product and an indication and does not extend across a pharmacological class.

No comparison of effect between these compounds is made on this page. Where head-to-head trials exist they are registered, and their results belong to the papers that report them.

Chemical & Molecular Characteristics

The FDA/NCATS Global Substance Registration System records eloralintide under UNII 73G3354J8W as a substance with two subunits: a 36-residue chain written CNTATCATGXLAEFLVRSSNNFGPKLPPTEVGSNTY, and a single glutamic acid residue recorded separately.

Three points qualify that record.

The molecule is cyclic, and the string is not. The cysteines at positions 1 and 6 of the recorded chain form the disulfide-bridged loop that defines the amylin family — human amylin carries the same bridge near its N-terminus. A linear reading of the sequence describes a different molecule from the one the register is describing, and the loop is not incidental: it is part of what the amylin receptors recognise.

The X is not an amino acid, and the second subunit is not a peptide chain. X is the register's placeholder for a residue with no single-letter representation. The separately recorded glutamic acid is characteristic of how these registers record an acylation linker rather than a second protein chain, and it should not be read as a second peptide.

The mass difference locates the modification. The register's calculated mass for the recorded backbone is approximately 3,547 g/mol; PubChem compound identifier 175663130 carries approximately 4,526 g/mol and the formula C201H319N49O65S2 for the complete molecule. The roughly 980-dalton gap is the modification chemistry, consistent with the once-weekly pharmacokinetics reported in rats, monkeys and humans ^[1]. CAS registry number 2883634-40-8 is carried by both registers.

Frequently Asked Questions

Scientific References

1. Briere DA, Qu H, Lansu K, et al.. Eloralintide (LY3841136), a novel amylin receptor agonist for the treatment of obesity: From discovery to clinical proof of concept Molecular metabolism; 2025. PMID 41109426 doi:10.1016/j.molmet.2025.102271
2. Billings LK, Hsia S, Bays H, et al.. Eloralintide, a selective amylin receptor agonist for the treatment of obesity: a 48-week phase 2, multicentre, double-blind, randomised, placebo-controlled trial Lancet (London, England); 2025. PMID 41207310 doi:10.1016/S0140-6736(25)02155-5
3. Bhattachar S, Tham LS, Tidemann-Miller B, et al.. Eloralintide, a selective, long-acting amylin receptor agonist for treatment of obesity: Phase 1 proof of concept Diabetes, obesity & metabolism; 2026. PMID 41559929 doi:10.1111/dom.70439
4. A Study of LY3841136 in Healthy and Overweight Participants 2022. NCT05295940
5. A Study of LY3841136 Compared With Placebo in Adult Participants With Obesity or Overweight 2024. NCT06230523
6. A Study of Eloralintide (LY3841136) and Eloralintide With Tirzepatide in Participants With Overweight or Obesity 2025. NCT06916065
7. Efficacy and Safety of Eloralintide (LY3841136) in Participants With Osteoarthritis Knee Pain and Obesity or Overweight 2026. NCT07353931
8. A Study of Eloralintide (LY3841136) in Participants With Obstructive Sleep Apnea and Obesity or Overweight 2026. NCT07369011

Every identifier above is resolved against PubMed, Crossref or ClinicalTrials.gov at build time, and the title returned by the register is compared with the title stored here. A page does not publish if a reference fails to resolve.

Research-Use Information

For in vitro research use only. This material is a laboratory reagent. It is not a drug, food, dietary supplement, or cosmetic and is not for human or veterinary use, including ingestion, injection, or any other administration. No information on this page describes or implies any effect in humans or animals. Sold only to researchers under our Terms of Sale.