Key facts
- The most common side effects were nausea and fatigue, mostly mild to moderate and more frequent at higher doses.[2]
- Phase 2 nausea: 11% at 1 mg, 64% at 6 mg and 33% at 9 mg, against 14% on placebo.[1]
- Fatigue reached 43% to 46% in the 9 mg and 6 to 9 mg arms, against 12% on placebo.[1]
- Slower dose escalation lowered side effects, and 1 mg and 3 mg were similar to placebo, per Lilly.[2]
- No deaths occurred in the phase 2 trial.[3]
Most Common Eloralintide Side Effects
In the 48-week phase 2 trial, the most common side effects were nausea and fatigue, with nausea affecting 11% to 64% of participants depending on dose, against 14% on placebo.[1]
| Arm | Nausea | Fatigue | Vomiting | Diarrhoea | Constipation |
|---|---|---|---|---|---|
| Placebo | 14% | 12% | 0/53 | 5/53 | 3/53 |
| 1 mg | 11% | 0% | 0/28 | 1/28 | 4/28 |
| 3 mg | 13% | 13% | 0/24 | 2/24 | 4/24 |
| 6 mg | 64% | 29% | 7/28 | 10/28 | 2/28 |
| 9 mg | 33% | 43% | 6/54 | 6/54 | 13/54 |
| 6 to 9 mg | 54% | 46% | 4/24 | 3/24 | 4/24 |
| 3 to 6 to 9 mg | 25% | 21% | 1/52 | 9/52 | 4/52 |
Source: Billings et al., The Lancet 2025.
Does Dose Escalation Reduce Side Effects?
Yes: in phase 2, nausea was 25% when eloralintide was escalated from 3 to 6 to 9 mg, against 64% when 6 mg was started directly, and Lilly says slower escalation lowered GI effects overall.[1][2]
Side Effects in Phase 1
In the 12-week phase 1 study, the most common events on eloralintide were decreased appetite (19%), headache (12%) and fatigue (11%), while nausea affected 8% and vomiting 4%.[4]
- 13 people left the study because of adverse events: 2 on placebo and 11 on eloralintide, 5 of them for COVID-19. None left because of nausea, vomiting or diarrhoea.[4]
- Three people on 12 mg had mood-related events and stopped treatment. The events resolved within 2 to 4 days.[4]
- In the single-dose study, 15 of 16 adverse events were mild.[5]
Eloralintide and Heart Rate
Heart rate went down, not up, in the 12-week phase 1 study, falling by 7.1 to 14.4 beats per minute at 3 to 12 mg against a 3.4 fall on placebo, with no symptomatic slow heart rate reported.[4]
Phase 2 heart rate data have not been published in the abstract or the registry results. Compare this with retatrutide, whose phase 2 showed dose-dependent heart rate increases that peaked at week 24. See eloralintide vs retatrutide.[6]
Is Eloralintide Safe?
Eloralintide’s safety is still being studied: phase 2 showed mostly mild to moderate GI effects and fatigue with no deaths, but larger phase 3 trials of 800 to 3,000 people each are needed before any regulator can judge it.[2][3][8]
Withdrawals from the phase 2 study because of adverse events were low: 2 on placebo and 0 to 2 per eloralintide arm.[3]
Side Effects With Tirzepatide (EloraTZP)
Combining eloralintide with tirzepatide raised discontinuation due to adverse events to 10.8% to 27.0%, against 2.9% with tirzepatide alone, in the 48-week EloraTZP phase 2b.[7]
Frequently Asked Questions
What are the side effects of eloralintide?
The most common were nausea and fatigue, plus vomiting, diarrhoea and constipation at higher doses. They were mostly mild to moderate and lower with slower dose escalation.
Does eloralintide cause nausea?
Yes, at higher doses. In phase 2, nausea affected 64% at 6 mg and 33% at 9 mg, but only 11% at 1 mg and 13% at 3 mg, against 14% on placebo.
Does eloralintide raise heart rate?
In the 12-week phase 1 study it lowered heart rate, by up to 14.4 beats per minute at 12 mg. Phase 2 heart rate data have not been published.
Is eloralintide safe?
It is still investigational. Trials so far reported mostly mild to moderate side effects and no deaths in phase 2, but phase 3 is needed to establish safety. Nothing here is medical advice.
Sources
- Billings LK, et al. Eloralintide phase 2, 48-week trial. The Lancet 2025;406:2631-2643. DOI 10.1016/S0140-6736(25)02155-5
- Eli Lilly press release, 6 Nov 2025: eloralintide phase 2 results
- ClinicalTrials.gov NCT06230523, eloralintide phase 2 posted results
- Bhattachar S, et al. Eloralintide 12-week multiple-dose phase 1. Diabetes, Obesity and Metabolism 2026;28(4):2651-2660. DOI 10.1111/dom.70439
- Briere DA, et al. Discovery and first-in-human study of eloralintide. Molecular Metabolism 2025;102:102271. DOI 10.1016/j.molmet.2025.102271
- Jastreboff AM, et al. Retatrutide phase 2. N Engl J Med 2023;389:514-526. DOI 10.1056/NEJMoa2301972
- Eli Lilly press release, 30 Sep 2026: EloraTZP (eloralintide + tirzepatide) phase 2b results
- ClinicalTrials.gov NCT07321886, ENLIGHTEN-1
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