Colulintide
An Eli Lilly obesity peptide built on a calcitonin-like backbone with a fatty side chain, meant to act on both amylin and calcitonin receptors. One phase 1 trial in 206 people finished in 2024 with no published result, and the programme is reported stopped.
Colulintide (LY3541105) is a 32-amino-acid peptide from Eli Lilly, classed as a dual amylin and calcitonin receptor agonist (DACRA) for obesity. Its chain matches salmon calcitonin at 21 of 32 positions and carries a 20-carbon fatty-acid chain (FDA GSRS UNII KX23AY2A39). Its only trial, a phase 1 study in 206 healthy adults and adults with overweight (NCT05380323), was completed in August 2024 with no results posted or published, and AdisInsight lists the programme as discontinued. No paper on PubMed names it, so nothing about how it works in people can be stated yet.
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Recommended Dosing
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Mechanism of action
Classed as a dual amylin and calcitonin receptor agonist by AdisInsight and in a 2024 review's table of obesity drugs (PMID 39676791, full text); its INN stem marks amylin mimics (ChEMBL). Amylin is a hormone released with insulin that slows stomach emptying and adds to the feeling of fullness (see the amylin entry), and the calcitonin receptor is its close relative; cagrilintide and petrelintide are other peptides made to act on both. No paper reports colulintide's receptor potency, half-life or effect on appetite or weight; the registry lists body weight as a phase 1 outcome but has no results (NCT05380323).
Primary uses
- Investigational: obesity and overweight (phase 1 completed 2024; reported discontinued)
Typical dosing
No dose in any paper, label or posted result. The phase 1 registry record describes single ascending, multiple ascending and escalating doses injected under the skin without giving any amount (NCT05380323), and Lilly has published nothing from it, so no figure is given here.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Regulatory status
Not approved anywhere: Drugs@FDA and the openFDA label endpoint hold no record for colulintide or LY3541105 (searched November 4, 2026), and ChEMBL records a highest clinical phase of 1 (CHEMBL6068472). Eli Lilly's only registered study is NCT05380323, a three-part phase 1 trial in 206 healthy adults and adults with overweight, completed August 27, 2024 with no results posted. AdisInsight lists development as discontinued (profile updated June 28, 2025), and Fierce Biotech reported that Lilly removed the DACRA listed as DACRA QW II and LY3541105 from its phase 1 pipeline in a fourth-quarter update; Lilly has published no result.
Status as of this entry's last review, November 4, 2026. Approvals, compounding rules and sport rules change; the regulatory tracker is checked more often.
What the studies show
No paper on PubMed names colulintide or LY3541105 (searched November 4, 2026). The one human study is the phase 1 trial below, known only from its registry record. A 2024 review that lists the drug in a table is in References.
Registry · 2022
Phase 1 in healthy adults and adults with overweight, completed, no results
Eli Lilly's first trial gave colulintide or placebo under the skin in three parts: single rising doses in healthy adults with a BMI from 18.5 to under 32, then repeated rising doses and an escalating schedule in adults with a BMI from 27 to under 40, none with diabetes. It enrolled 206 people at two US clinics between May 2022 and August 2024. The main measure was drug-related side effects over up to 26 weeks, with blood levels and, in the repeated-dose part, weight change as secondary measures. The record gives no dose amounts and no results.
NCT05380323 · ClinicalTrials.gov record
References
- [pubmed] Sidrak WR, et al. "Approved and Emerging Hormone-Based Anti-Obesity Medications: A Review Article." Indian J Endocrinol Metab, 2024;28(5):445-460. PMID: 39676791.
- [clinicaltrials] ClinicalTrials.gov NCT05380323: "A Phase 1, Randomized, Placebo-Controlled, Dose-Escalation Study to Evaluate the Safety, Tolerability, and PK of LY3541105 Following Single Doses in Healthy/Overweight Participants and Multiple Doses in Overweight Participants" Eli Lilly and Company. Randomised, double-masked, placebo-controlled, three parts (A: single ascending doses, BMI 18.5 to under 32; B: multiple ascending doses, BMI 27 to under 40; C: escalating doses, BMI 27 to under 40), all under the skin; adults 21 to 65 without diabetes; 206 enrolled at two US sites (Lenexa, Kansas and San Antonio, Texas), May 10, 2022 to August 27, 2024, completed. Primary outcome drug-related adverse events up to 26 weeks; secondary outcomes blood levels and, in part B, body weight change. No dose amounts in the record and no results posted (last update June 2025). Registry record read November 4, 2026.
- [other] FDA Global Substance Registration System, Colulintide, UNII KX23AY2A39 (protein; INN 13510, CAS 2891912-36-8, NCI Thesaurus C213404; codes LY3541105 and LY-3541105), read November 4, 2026: a 32-residue chain ASHLSTAVLGKLSXELHKLEDYPRTDVGAESP with an acetylated N-terminal alanine, 2-aminoisobutyric acid at position 14, a C-terminal prolinamide, and lysine 11 carrying an icosanedioic acid (C20 diacid) chain on a gamma-glutamyl and two aminoethoxy-ethoxy-acetyl linkers. https://gsrs.ncats.nih.gov/ginas/app/beta/substances/KX23AY2A39
- [other] ChEMBL molecule CHEMBL6068472 (COLULINTIDE), read November 4, 2026: molecule type Protein; synonyms Colulintide, LY-3541105, LY3541105; USAN 2024, stem -tide defined as 'peptides: amylin derivatives or mimics'; highest clinical phase 1; no mechanism record. https://www.ebi.ac.uk/chembl/compound_report_card/CHEMBL6068472/
- [other] AdisInsight (Springer Nature) drug profile 800068553, Colulintide, read November 4, 2026: a synthetic peptide originated by Eli Lilly and Company; alternative names DACRA QW II and LY-3541105; mechanism amylin receptor agonist and calcitonin receptor agonist; development status discontinued, highest phase phase 1 in obesity; last event June 28, 2025, no recent reports of development for the phase 1 programme in the USA. https://adisinsight.springer.com/drugs/800068553
- [other] Fierce Biotech, "Eli Lilly lops Alzheimer's and obesity assets from pipeline in Q4 update", read November 4, 2026: reports that Lilly removed a dual amylin calcitonin receptor agonist (DACRA), listed as DACRA QW II and LY3541105, from its phase 1 obesity pipeline in a fourth-quarter pipeline update, and that Lilly entered the DACRA field through a 2017 partnership with KeyBioscience. The page as read prints no publication date. https://www.fiercebiotech.com/biotech/eli-lilly-lops-alzheimers-and-obesity-assets-pipeline-q4-update
- [other] US FDA, Drugs@FDA and the drug label endpoint (openFDA), searched November 4, 2026: no application and no label record for colulintide or LY3541105.
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This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.