Eloralintide

What is Eloralintide?

Eloralintide (development code LY3841136) is an experimental drug from the pharmaceutical company Eli Lilly. It is a selective amylin receptor agonist, which means it activates a specific receptor in the body. The drug is being developed to treat obesity and overweight. As a synthetic peptide hormone, it mimics the body's own satiety hormone, amylin. In a 48-week phase 2 study, eloralintide as a monotherapy achieved weight loss of up to 20.1% without any additional drug combination [2].

Structurally, the eloralintide peptide consists of 37 amino acids and is based on the native amylin molecule. It has been optimized in two ways: a C20 fatty acid side chain binds to the blood protein albumin, extending the half-life to about 13-15 days. In addition, a methylene thioacetal bridge replaces the unstable disulfide bridge of natural amylin for increased chemical stability [1]. This molecular design allows for a once-weekly subcutaneous injection.

Receptor selectivity is the central pharmacological feature of eloralintide: the drug activates the human amylin-1 receptor (AMY1R) about 12 times more strongly than the calcitonin receptor (CTR) and 11 times more strongly than the amylin-3 receptor (AMY3R) [1]. This targeted AMY1R preference is considered the primary reason for its improved tolerability profile compared with non-selective amylin analogs.

How is Eloralintide used?

In all clinical studies, eloralintide is administered exclusively as a subcutaneous injection once a week. There are no scientific data on oral, nasal, or alternative forms of administration. The subcutaneous injection is typically given into the subcutaneous fat tissue of the abdomen, thigh, or upper arm, similar to established peptide hormone therapies for weight loss.

As an investigational drug in clinical development, eloralintide does not yet have market approval from agencies such as the FDA or EMA, and it is not regularly available by prescription. In clinical trials, Eli Lilly provides the drug as a ready-to-use injection solution, so no reconstitution of freeze-dried powder (lyophilisate) is needed [3][5].

No documented gray market trade is currently known for eloralintide. Hypothetically obtaining it through unregulated online channels carries significant risks due to a lack of quality controls, unverified purity levels, and missing data on safe use. For more well-founded tips on minimizing risks, see the section Protection when ordering.

From vial to use: What does that mean in practice?

Since eloralintide is not commercially available, there is no documented reconstitution protocol for home use. In studies, Eli Lilly uses ready-to-use dissolved preparations for direct injection [3][5]. All information here describes only the methodology of the clinical study drugs and is not a guide for self-administration.

The doses of eloralintide studied in clinical trials range from 0.04 mg to 12 mg per injection. The concentration of the study solutions is designed so that the respective dose can be given in a typical injection volume of 0.5 to 1.0 ml. The exact concentration parameters of the investigational drugs are not fully disclosed in the public approval documents.

For general handling of peptide vials, as well as their proper reconstitution and storage, a step-by-step guide to mixing and storing is available in the tools section.

How does Eloralintide work?

The body's own peptide hormone amylin is produced together with insulin in the beta cells of the pancreas and is released after meals to control energy intake through three key physiological mechanisms:

• Satiety: Amylin signals to the brain that the stomach is full, thereby reducing the feeling of hunger.
• Stomach emptying: It slows down gastric emptying, which prolongs the feeling of fullness after a meal.
• Blood sugar: It suppresses the release of glucagon after eating, thereby stabilizing blood sugar levels.

Eloralintide mimics these amylin effects with a prolonged half-life of 13-15 days and selective AMY1R binding. Since activation of the calcitonin receptor is thought to be responsible for side effects like taste disturbances, the 12-fold AMY1R selectivity reduces unwanted reactions [1]. In a preclinical model, eloralintide caused significantly less taste aversion than the non-selective amylin agonist cagrilintide [1].

Unlike pure GLP-1 receptor agonists such as semaglutide or multi-receptor agonists like retatrutide, eloralintide targets the amylin signaling pathway in isolation. This distinct mechanism of action allows for use both as a monotherapy and in complementary combinations with incretin mimetics.

What does clinical research on Eloralintide show?

The clinical evidence for eloralintide is based on phase 1 and phase 2 studies on dose finding, safety, and weight loss in obesity:

Phase 1: Initial safety data

In the phase 1 dose-escalation study (NCT05295940), 48 healthy volunteers received single doses of eloralintide ranging from 0.04 mg to 12 mg. The drug was well tolerated; 15 of 16 documented adverse events were classified as mild [1].

The multi-dose phase 1b study over 12 weeks showed a placebo-adjusted weight loss of 11.3% after three months at the highest 12 mg dose [4]. Gastrointestinal side effects occurred at a low frequency.

Phase 2: The Lancet study

The 48-week phase 2 study (NCT06230523) with 263 participants (average BMI 39.1, without type 2 diabetes) was published in The Lancet in November 2025 [2]. The study examined once-weekly subcutaneous administration of various doses of eloralintide compared with placebo.

The study results on weight loss are summarized in the table below:

* In the publication summaries, the exact percentage values for the intermediate dose arms were not reported in isolation; the overall range of dose-dependent weight loss spanned from 9.5% to 20.1% [2].

All dose arms achieved a statistically significant weight reduction compared with placebo, with no apparent plateau in effect at the highest doses [2]. A gradual dose escalation from 3 mg to 9 mg significantly reduced the therapy discontinuation rate to 21%, compared with 43% for an initial 9 mg dose, highlighting the clinical importance of slow dose titration.

Discontinuations due to side effects occurred in 43-46% of those treated in the 9 mg cohorts (placebo: 12%), primarily driven by nausea and fatigue [2]. The reported reduction values are based on the efficacy estimand, assuming full therapy adherence.

Combination with Tirzepatide

Eli Lilly is testing eloralintide in combination with the dual GIP/GLP-1 agonist tirzepatide to synergistically link amylin and incretin signaling pathways. After the phase 1 combination study (NCT06916065) was completed, phase 2 testing is currently underway in type 2 diabetes (NCT06603571) [5].

Phase 3 and outlook

Eli Lilly plans to start phase 3 registration studies for eloralintide as a monotherapy between late 2025 and early 2026. In parallel, combination regimens with incretin mimetics are being further developed [2].

What side effects are known for Eloralintide?

The side effect profile of eloralintide in clinical trials is largely characterized by gastrointestinal symptoms and fatigue:

• Nausea: The most common side effect, occurring in a dose-dependent manner, with a focus at higher doses.
• Fatigue: Frequently documented, especially during the initial treatment phase.
• Vomiting: Occurs less often than nausea and is concentrated at the highest dose levels.
• Injection site reactions: Local skin irritation at the injection site is occasionally reported.

Due to its selective AMY1R binding, eloralintide shows a lower incidence of gastrointestinal complaints (up to 10% in phase 1) than non-selective amylin agonists like cagrilintide [1][4].

However, discontinuation rates of up to 46% at the 9 mg dose in phase 2 demonstrate dose limitations with rapid escalation, which is why a gradual dose increase is necessary to optimize tolerability [2].

Open research questions and knowledge gaps on Eloralintide

• Long-term safety: Reliable safety data beyond the maximum studied 48-week horizon are currently completely lacking.
• Phase 3 results: Phase 3 studies to confirm efficacy and safety in large populations are still pending.
• Cardiovascular and renal effects: Specific data on organ protection for the heart and kidneys are not yet available for eloralintide.
• Body composition: Selective fat mass loss was observed preclinically [1], but detailed human data on body composition are missing.
• Muscle mass preservation: The exact ratio of fat to lean mass loss at the highest doses is insufficiently characterized.
• Specific patient groups: Clinical data on geriatric patients, pregnancy, adolescents, or severe pre-existing conditions are lacking.

Eloralintide vs. Cagrilintide: What is the difference?

Despite belonging to the same drug class, eloralintide and cagrilintide differ fundamentally in receptor selectivity, half-life, and stage of development:

A direct head-to-head comparison of the two substances does not exist, so differences in weight loss may also be due to differing study designs and treatment durations.

Conclusion on Eloralintide as an amylin agonist

With up to 20.1% weight loss in phase 2, eloralintide marks a milestone among monotherapy amylin agonists and achieves effectiveness in the range of established GLP-1 therapies through a distinct receptor pathway. Its pronounced AMY1R selectivity offers pharmacological advantages regarding gastrointestinal side effects, but at high target doses it requires a strict titration schedule to reduce discontinuation rates.

Confirming the clinical benefit-risk profile rests with the phase 3 studies scheduled for 2025/2026, ahead of any potential approval. For further analyses of related peptide drugs, see the Peptide Library.