Eloralintide: The Amylin Analogue Entering the Weight-Management Race

Eloralintide is an investigational once-weekly peptide from Eli Lilly that selectively activates the amylin receptor, a different pathway from the GLP-1 and GIP receptors targeted by semaglutide, tirzepatide and retatrutide. In a 48-week phase 2 trial published in The Lancet in 2025, participants on eloralintide lost between 9.5% and 20.1% of body weight compared with 0.4% on placebo, with gastrointestinal side effects at the lower doses similar to placebo. It has no MHRA marketing authorisation and is available in the UK only as a laboratory research chemical. This article explains what amylin does, what eloralintide showed, and how it fits alongside the incretin class.

What is amylin and why does it matter?

Amylin is a 37-amino-acid hormone secreted by the beta cells of the pancreas alongside insulin. It acts mainly in the brainstem and hypothalamus, where it is studied for slowing gastric emptying, suppressing glucagon release after meals and promoting satiety. In people with type 1 diabetes it is largely absent; in obesity, the amylin signalling pathway appears to be intact but under-stimulated.

Native amylin has two problems as a drug candidate: it aggregates into amyloid fibrils, and it has a half-life of minutes. The first amylin analogue, pramlintide, solved the aggregation issue and was approved in the United States in 2005 as an adjunct to insulin, but it still required injection with every meal and produced modest weight effects. The modern amylin analogues, including cagrilintide and eloralintide, add lipid side chains for once-weekly pharmacokinetics.

The amylin receptor itself is a complex: the calcitonin receptor combined with one of three receptor activity-modifying proteins (RAMP1, 2 or 3). Many amylin analogues also activate the calcitonin receptor on its own. Eloralintide is described by Lilly as a selective amylin receptor agonist, meaning it favours the amylin receptor complex over the bare calcitonin receptor, which is thought to be relevant to its tolerability profile.

Eloralintide phase 2 results

Lilly's phase 2 trial enrolled 263 adults with obesity, or overweight with at least one weight-related comorbidity, and without type 2 diabetes. Participants were randomised to one of several weekly eloralintide doses, with and without dose escalation, or placebo, for 48 weeks. Results were presented at ObesityWeek in November 2025 and published simultaneously in The Lancet.

Every eloralintide arm met the primary endpoint. Mean weight reduction ranged from 9.5% at the lowest dose to 20.1% at the highest, versus 0.4% on placebo. The most common adverse events were mild to moderate gastrointestinal symptoms and fatigue, concentrated in the higher-dose arms. At the 1 mg and 3 mg doses, gastrointestinal adverse events occurred at rates similar to placebo, and slower escalation reduced their incidence at higher doses.

The 20.1% figure at 48 weeks is notable because it sits in the same range as tirzepatide's 72-week SURMOUNT-1 result, achieved through a mechanism that does not touch the GLP-1 receptor at all. As with any cross-trial comparison, the populations and durations differ, and phase 3 will be the real test.

How eloralintide compares with other amylin analogues

The amylin class has become one of the most active areas of metabolic research. The table below summarises the main compounds and the published figures, all of which come from separate trials and should be read as indicative.

The distinguishing feature of eloralintide is selectivity. Cagrilintide is often characterised as a dual amylin and calcitonin receptor agonist (DACRA), while eloralintide is engineered to favour the amylin receptor. Whether that selectivity translates into a meaningfully better tolerability profile at equivalent efficacy is one of the questions the phase 3 programme is designed to answer.

Why researchers are combining amylin with incretins

Amylin and GLP-1 act on overlapping but distinct pathways. Both reduce food intake, but amylin does so partly through the area postrema in the brainstem, while GLP-1 receptor agonists act more broadly across hypothalamic and reward circuits. Preclinical work suggests the effects are additive, which is why Novo Nordisk built CagriSema and why Lilly has announced trials of eloralintide alongside tirzepatide.

There is also a tolerability rationale. If a comparable weight effect can be reached with a lower dose of each agent, the gastrointestinal burden may fall. Early evidence for that idea comes from the eloralintide phase 2, where the lower-dose arms produced meaningful weight reduction with placebo-level gastrointestinal events. Researchers are additionally interested in body composition: some amylin-class data suggest a higher proportion of fat loss relative to lean mass, though this remains to be confirmed in larger trials.

Eloralintide UK legal status

Eloralintide has no marketing authorisation from the MHRA, the EMA or the FDA. It cannot be prescribed in the UK and is not available through the NHS or private clinics. Any seller offering it to UK consumers as a weight-loss product is supplying an unlicensed medicine contrary to the Human Medicines Regulations 2012.

It is not a controlled drug under the Misuse of Drugs Act 1971, so supplying, buying and possessing eloralintide as a research chemical is lawful, provided it is labelled and sold strictly for laboratory research. That is the basis on which Calibre supplies its 20 mg eloralintide pen. Our article on whether peptides are legal in the UK explains the framework.

Evaluating research-grade eloralintide

Eloralintide is a newer compound than retatrutide or tirzepatide, and the research supply chain is correspondingly less mature. That makes independent verification essential.

• A batch-specific certificate of analysis from an independent laboratory. Calibre eloralintide batches are tested by Janoshik Analytical and the COAs are published on the site's COA page.
• HPLC purity above 99% and a mass spectrometry result consistent with the compound's theoretical mass.
• Measured quantity close to the labelled 20 mg.
• Storage guidance: as a lipidated peptide in solution, eloralintide should be refrigerated and protected from light, as with other pens in this class.
• A supplier that does not publish protocols, dosing or benefit claims. Eloralintide has no approved use anywhere, so any such claims are both unlawful and unsupported.

What happens next

Lilly moved eloralintide into phase 3 following the 2025 phase 2 data, and the first pivotal trials are recruiting. Readouts are expected over the next two to three years, alongside combination studies with tirzepatide. For the amylin class as a whole, the CagriSema REDEFINE programme and the amycretin trials will provide additional context.

For UK laboratories, eloralintide offers something the incretin class does not: a well-characterised, potent research tool for the amylin receptor pathway, with published human pharmacology to anchor in-vitro and comparative work. As with retatrutide, its regulatory status will not change until phase 3 completes and a marketing authorisation is granted, which is some years away.