EloraTZP Results Explained: Eloralintide + Tirzepatide Phase 2b Data

Back in August, in my eloralintide research guide, I said the biggest open question wasn't how eloralintide works alone. It was what happens when Lilly pairs it with tirzepatide.

On September 30, 2026, we got the answer. The headline number is big: 23.3% average weight loss in 48 weeks. That beat tirzepatide alone by a wide margin.

But there's a catch that most headlines skipped. More people quit the combo because of side effects. I'll break down the good, the bad, and what it all means in plain English.

Quick Facts (TL;DR)

• What it is: EloraTZP is Eli Lilly's investigational combination of eloralintide (an amylin agonist) and tirzepatide (a GIP/GLP-1 agonist).
• Best result: 23.3% average weight loss (54.1 lbs) at the highest dose combo.
• Tirzepatide alone: 14.8% (34.4 lbs) at its highest dose.
• Who was studied: 367 adults with obesity or overweight AND type 2 diabetes.
• The catch: Up to 27% of people in some combo groups quit because of side effects, compared to 2.9% on tirzepatide alone.
• Status: Not approved. Phase 3 trials are planned to start by the end of 2026.

What Is EloraTZP?

EloraTZP is two compounds used together. The name is just the two names mashed up: "Elora" for eloralintide and "TZP" for tirzepatide.

Eloralintide copies a hormone called amylin. Your pancreas releases amylin at the same time as insulin after you eat. One of its jobs is telling your brain you're full.

Tirzepatide is the compound in Zepbound and Mounjaro. It copies two gut hormones, GIP and GLP-1. These hormones also help control hunger and blood sugar.

Put them together, and you're hitting three hunger and fullness signals at once: amylin, GIP, and GLP-1. Lilly also designed eloralintide to mostly skip a related receptor (the calcitonin receptor) that's linked to nausea in older amylin compounds.

Want the full science on how eloralintide works by itself? Read my eloralintide research guide.

Why Combine Amylin With Tirzepatide?

Think of hunger like a group chat with your brain. Tirzepatide sends two "I'm full" messages. Amylin sends a third, through a totally different route.

The idea is simple: more fullness signals from different directions should mean less eating and more weight loss than any one compound alone.

Novo Nordisk is betting on the same idea with CagriSema (cagrilintide + semaglutide). So this is really Lilly's answer to CagriSema.

How the Study Worked

Here's the setup, in plain terms:

• Phase 2b: This is a mid-stage trial. It tests different doses to find the best ones before the big, final Phase 3 trials.
• Who: 367 adults in the U.S. and Argentina. Every person had obesity or overweight and type 2 diabetes.
• How long: 48 weeks (about 11 months).
• Double-blind and placebo-controlled: Neither the participants nor the researchers knew who got what. Some people got a placebo (a fake shot with no active drug) for comparison.
• Groups: People were split into 10 groups: placebo, eloralintide alone, tirzepatide alone, or different EloraTZP dose combos. That's only about 37 people per group, which matters later.
• Two shots: The compounds were given as separate injections, not one combined shot.
• Slow start: Everyone started on a low dose, and the dose went up every 4 weeks until they reached their target.

At the start, the average person weighed 232.4 lbs and had an A1C of 8.1%.

Quick note on A1C: A1C shows your average blood sugar over the past 2 to 3 months. Under 5.7% is considered normal. 6.5% or higher is the range for diabetes. So 8.1% means blood sugar was running high.

The Results: EloraTZP Phase 2b Data

Here are the numbers Lilly reported at 48 weeks.

Source: Eli Lilly, September 30, 2026. Results presented at EASD 2026 in Milan, Italy. These are "efficacy estimand" numbers (explained below).

What Stands Out

1. The combo beat tirzepatide alone by about 20 pounds

The top EloraTZP dose averaged 54.1 lbs lost. Tirzepatide at its max dose averaged 34.4 lbs. That's roughly 20 extra pounds over 11 months.

2. A lower tirzepatide dose did better with eloralintide added

This is the detail I find most interesting. Elora 6 mg + TZP 5 mg hit 19.4% weight loss. That beat tirzepatide 15 mg alone (14.8%), even though it used only one-third of the tirzepatide dose.

In simple terms: adding amylin seemed to do more than just tripling the tirzepatide dose.

3. Eloralintide alone looked weaker than last year. Here's why.

In last year's Phase 2 trial, eloralintide alone hit up to 20.1% weight loss. In this trial, it topped out at 12.3%. Did it stop working? No.

The big difference is who was studied. This trial only included people with type 2 diabetes. People with type 2 diabetes usually lose less weight on these compounds than people without it. That's been true for tirzepatide and semaglutide too.

Also, the 9 mg group (11.1%) did slightly worse than the 6 mg group (12.3%). With only about 37 people per group, small differences like that can just be noise.

4. Blood sugar dropped a lot

The top combo dropped A1C by 2.9 points on average, compared to 2.4 for tirzepatide alone. Starting from 8.1%, that puts the average close to the normal range.

The Catch: Side Effects and Dropouts

Here's the part most headlines buried.

Side effects were mostly stomach-related. Think nausea, vomiting, and diarrhea. Lilly says they were mostly mild or moderate and happened mainly while the dose was going up. But they happened more often in the combo groups than with either compound alone.

More people quit. Here's how many people stopped because of side effects:

So in the worst combo group, about 1 in 4 people quit. That's a real problem. A compound only works if people can stay on it.

The 16.7% placebo dropout rate is weirdly high, since placebo has no active drug. That's another sign these groups were small, and the numbers can jump around.

The "efficacy estimand" fine print. Lilly's headline numbers are based on what would happen if everyone had stayed on treatment the whole time. When up to a quarter of a group quits, the real-world average is usually lower. Keep that in mind when you see "23.3%."

Two shots, not one. In this trial, the compounds were separate injections. A single combined shot hasn't been tested yet.

What Happens Next: EloraTZP Phase 3

Lilly says it will start Phase 3 trials of EloraTZP by the end of 2026. Two important changes:

1. One shot. Phase 3 will test a co-formulation, meaning both compounds in a single injection.
2. A slower dose ramp. Lilly says it will use an "optimized escalation schedule." My read: they're raising the dose more slowly to cut down on the stomach side effects and dropouts we saw here.

Eloralintide by itself is already in Phase 3. That program is called ENLIGHTEN. It includes trials in people with and without type 2 diabetes, people with sleep apnea, and people already on a weekly GLP-1-type treatment who still have excess weight.

Phase 3 trials usually take a couple of years. Approval, if it ever happens, is realistically years away.

EloraTZP vs CagriSema vs Retatrutide

These are the three big next-generation compounds people are searching about. Here's how they differ:

• EloraTZP (Lilly): amylin + GIP + GLP-1. Two compounds combined. Phase 2b done, Phase 3 starting.
• CagriSema (Novo Nordisk): amylin (cagrilintide) + GLP-1 (semaglutide). Two compounds combined. Further along in development.
• Retatrutide (Lilly): GIP + GLP-1 + glucagon in one molecule. Phase 3 done, with a regulatory filing planned for early 2027. See my retatrutide guide.

Important: None of these have been tested head-to-head. Their trials used different people, different lengths, and different doses. So you can't fairly say one "beats" another yet. Anyone who tells you otherwise is guessing.

Honest Gaps: What We Still Don't Know

• Only Phase 2 data. 367 people split into 10 groups is small. Phase 3 will be much bigger.
• Only people with type 2 diabetes. We don't have EloraTZP data in people without diabetes yet.
• Only 48 weeks. We don't know about long-term safety or what happens to weight after stopping.
• No single-shot data. Phase 3's combined injection hasn't been tested.
• Not fully published yet. These results came from a press release and a conference presentation. A full peer-reviewed paper with all the details hasn't come out yet.
• Real-world numbers will likely be lower. The headline numbers assume everyone stayed on treatment.

A Note on Availability

EloraTZP isn't a product you can buy. It's an investigational combination that only exists inside Lilly's clinical trials. If you see eloralintide or tirzepatide listed by research vendors, they're sold separately as Research Use Only (RUO) materials. Seeing two RUO compounds listed separately does not recreate a clinical trial. Trials use verified purity, controlled dosing, and medical oversight that a lab listing doesn't provide.

Frequently Asked Questions

Sources

• Eli Lilly and Company. "Lilly's EloraTZP (combination of eloralintide and tirzepatide) delivered greater weight loss and A1C reduction vs. tirzepatide 15 mg in adults with obesity and type 2 diabetes." September 30, 2026. investor.lilly.com
• ClinicalTrials.gov, NCT06603571 (EloraTZP Phase 2b study). clinicaltrials.gov/study/NCT06603571
• Research Pep Hub. Eloralintide Research Guide: Amylin-Agonist Mechanism & Phase 2 Trial Data

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Tags: EloraTZP, eloralintide, tirzepatide, amylin, Eli Lilly, weight loss research, obesity research, CagriSema comparison, EASD 2026