For vendorsJoin free
For vendorsSign inSign up free
← Back to Blog
Compound Deep-Dive

Eloralintide vs Retatrutide: Mechanism, Trial Data and Price

By , co-founder & editorial lead · Published  · 11-minute read

Share
Summarize this article with AIOpens the assistant in a new tab with the article link and PeptidePrices as the source.
ChatGPTPerplexityGrokGoogle AI ModeClaude
Quick referenceEloralintide
View live prices & vendors
In this article

Eloralintide and retatrutide are both Eli Lilly obesity candidates, both given as once-weekly subcutaneous injections in clinical trials, and both unapproved. They act on different hormone systems. Eloralintide is a selective amylin receptor agonist whose one completed efficacy trial, a 263-person Phase 2 study published in The Lancet, produced up to 20.1% mean weight loss at 48 weeks. Retatrutide is a GIP, GLP-1 and glucagon receptor triple agonist with peer-reviewed Phase 3 data: up to 25.0% mean weight loss at 80 weeks in the 2,339-person TRIUMPH-1 trial, published in The New England Journal of Medicine on September 29, 2026.

On PeptidePrices, as of October 21, 2026, the lowest research-listing price per 10 mg is $85.00 for eloralintide across 10 vendors and $20.70 for retatrutide across 247 vendors. Live figures are on the eloralintide price page and the retatrutide price page, where retatrutide is listed under its PeptidePrices label, GLP-3R.

Eloralintide vs Retatrutide at a glance

Eloralintide Retatrutide
Lilly code LY3841136 LY3437943
Class Selective amylin receptor agonist GIP / GLP-1 / glucagon receptor triple agonist
Receptor targets Amylin receptors, with AMY1R preferred over the calcitonin receptor in human cell assays GIP receptor, GLP-1 receptor, glucagon receptor
Development stage (Oct 21, 2026) Phase 3 (ENLIGHTEN program, first trial started December 2025); not approved Phase 3 readouts complete in obesity and type 2 diabetes; Lilly plans a U.S. filing in Q1 2027; not approved
Headline trial result Up to -20.1% body weight at 48 weeks vs -0.4% placebo (Phase 2, n=263, efficacy estimand) Up to -25.0% at 80 weeks vs -3.9% placebo (Phase 3 TRIUMPH-1, n=2,339, treatment-regimen estimand)
Dosing frequency in trials Once weekly, subcutaneous Once weekly, subcutaneous
Most common adverse events Nausea and fatigue Nausea, diarrhea, constipation and vomiting
PeptidePrices lowest price per 10 mg $85.00 (after vendor coupon) $20.70 (after vendor coupon)
PeptidePrices median price per 10 mg $155.70 $63.99
Vendors tracked 10 247
COA coverage 90% of vendors publish COAs; 2 vendors have an issuer-verified COA on the listing 99% of vendors publish COAs; 164 vendors have an issuer-verified COA on the listing

Prices and vendor counts are PeptidePrices observations as of October 21, 2026. Trial figures are from the sources linked in each section below. "Up to" refers to the best-performing study arm.

Mechanism: one hormone system versus three

Eloralintide targets amylin receptors

Amylin is a peptide hormone released from pancreatic beta cells alongside insulin after a meal. It signals satiety through receptors in the brain. Amylin receptors are built from the calcitonin receptor paired with a receptor activity-modifying protein, which is why amylin drugs can also touch the calcitonin receptor itself.

Lilly's design goal for eloralintide is selectivity within that family. Lilly's medical-information summary reports about 12-fold greater potency at the human amylin-1 receptor (AMY1R) than at the calcitonin receptor in cell assays, citing the company's Molecular Metabolism discovery paper. The same summary states that the functional significance of this selectivity in humans still needs research. Lilly's Phase 2 press release frames it as a class bet: the company believes "molecule specificity is important" for amylin drugs.

Eloralintide does not act on GLP-1, GIP or glucagon receptors. That makes it a candidate to stack on top of an incretin drug, and Lilly is testing exactly that: ENLIGHTEN-6 (NCT07392190) enrolls people with persistent obesity who already take a weekly incretin, and the AMPLIFY-1 and AMPLIFY-2 Phase 3 trials (NCT07881432, NCT07881458) test EloraTZP, a combination with GLP-2T. Our EloraTZP Phase 2 write-up covers that combination's 48-week data.

Retatrutide targets GIP, GLP-1 and glucagon receptors

Retatrutide is a single peptide that activates three receptors. The 2023 Phase 2 paper describes it as an agonist of the glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon receptors. GLP-1 and GIP receptor activity is the same dual-incretin base used by GLP-2T. The added glucagon receptor activity is Lilly's stated rationale for going further: glucagon signalling is associated with energy expenditure and liver fat metabolism, on top of the appetite effects of the incretin pathways.

The practical difference: retatrutide stacks three receptor actions into one molecule, while eloralintide hits one receptor family and is being developed both alone and paired with incretin drugs.

Eloralintide trial data

Phase 2 (NCT06230523): peer-reviewed

The Phase 2 trial (NCT06230523) randomized 263 adults at 46 U.S. sites. Participants had a BMI of 30 or higher, or 27 or higher with a weight-related condition, and no type 2 diabetes. Mean baseline weight was 109.1 kg, mean BMI was 39.1 and 78% were female. Treatment ran 48 weeks, with once-weekly subcutaneous injections across six active arms and placebo. The results were presented at ObesityWeek 2025 and published in The Lancet (Billings et al., 2025; funded by Eli Lilly).

Every eloralintide arm beat placebo on the primary endpoint. Mean weight change at 48 weeks ranged from -9.5% in the lowest-dose arm to -20.1% in the best-performing arm, versus -0.4% on placebo (efficacy estimand), per Lilly's November 6, 2025 release. The Lancet authors describe the reductions as dose-dependent.

Per the Lancet abstract, nausea ranged from 11% to 64% across eloralintide arms versus 14% on placebo, and fatigue from 0% to 46% versus 12% on placebo. Both were more frequent in the higher-exposure arms.

Three details matter when reading these results:

  • The 20.1% is an efficacy estimand. It models results as if participants stayed on treatment. Lilly's release did not report a treatment-regimen figure, the more conservative analysis Lilly leads with for retatrutide's Phase 3 data.
  • Arms were small. Group sizes ran from 24 to 54 participants, and Lilly's release notes that some reported endpoints were not adjusted for multiplicity.
  • Escalation changed tolerability. Nausea ranged from 64% in one fixed-level arm to 25% in the most gradual escalation arm. Lilly links slower escalation to lower adverse-event rates.

Phase 3: ENLIGHTEN, under way

ClinicalTrials.gov lists five ENLIGHTEN Phase 3 trials as recruiting on October 21, 2026, with no results yet:

  • ENLIGHTEN-1 (NCT07321886): about 1,980 adults with obesity or overweight without type 2 diabetes; primary endpoint is percent weight change at week 64; started February 6, 2026; estimated primary completion March 2028.
  • ENLIGHTEN-2 (NCT07282600): about 1,035 adults with type 2 diabetes; started December 15, 2025.
  • ENLIGHTEN-3 (NCT07369011): about 800 adults with obstructive sleep apnea.
  • ENLIGHTEN-4 (NCT07353931): about 900 adults with knee osteoarthritis pain.
  • ENLIGHTEN-6 (NCT07392190): about 900 adults with persistent obesity on a weekly incretin.

Retatrutide trial data

Phase 2 (2023): the 48-week benchmark

The Phase 2 trial in The New England Journal of Medicine enrolled 338 adults with obesity or overweight. At 48 weeks, least-squares mean weight change ranged from -8.7% in the lowest-dose arm to -24.2% in the highest-dose arm, versus -2.1% on placebo. This is the closest like-for-like comparison to eloralintide's Phase 2: same sponsor, same duration and a similar population without diabetes.

TRIUMPH-1 (NCT05929066): peer-reviewed Phase 3

TRIUMPH-1 (NCT05929066) randomized 2,339 adults with obesity and no diabetes to one of three once-weekly retatrutide arms or placebo for 80 weeks. Per the NEJM paper, mean weight change under the treatment-regimen estimand was -17.6%, -23.7% and -25.0% across the three arms, versus -3.9% on placebo. In the 574-participant knee osteoarthritis subgroup, pain scores improved more than with placebo, and in the 243 participants with obstructive sleep apnea, the top arm had 32.1 fewer events per hour versus 9.6 on placebo (intention-to-treat).

Lilly's May 21, 2026 topline release reported the efficacy-estimand figure for the top arm as 28.3%, and its adverse-event rates versus placebo: nausea 42.4% vs 14.8%, dysesthesia (abnormal skin sensation) 12.5% vs 0.9%, and discontinuation due to adverse events 11.3% vs 4.9%.

TRIUMPH-2 (NCT05929079): peer-reviewed, type 2 diabetes

TRIUMPH-2 (NCT05929079) randomized 1,152 adults with obesity and type 2 diabetes for 80 weeks. The Lancet paper reports treatment-regimen weight change of -11.9%, -16.8% and -18.8% across the three retatrutide arms, versus -5.1% on placebo. Nausea occurred in up to 28% of retatrutide participants versus 8% on placebo. Permanent discontinuation for adverse events or death ranged from 4% to 12% across retatrutide arms, versus 5% on placebo.

TRIUMPH-3 (NCT05882045): topline, pending peer review

Lilly reported on July 23, 2026 that TRIUMPH-3 (NCT05882045), in adults with severe obesity and established cardiovascular disease, reached up to 22.6% weight loss at 80 weeks versus 3.2% in the control group, with discontinuation for adverse events up to 13.5% versus 4.8%, per pharmaphorum's report of the announcement. These are company-reported topline figures, pending peer review. In the same announcement Lilly said it plans to file for U.S. approval in the first quarter of 2027.

Why the headline numbers do not compare directly

No trial has tested eloralintide against retatrutide. On October 21, 2026, ClinicalTrials.gov listed no study that includes both drugs. Every comparison here is cross-trial, and four differences drive most of the gap between 20.1% and 25.0%:

  1. Duration. Eloralintide's figure is at 48 weeks; TRIUMPH-1's is at 80 weeks. At 48 weeks, retatrutide's best arm produced -24.2% in its own Phase 2 trial.
  2. Estimand. Eloralintide's 20.1% is an efficacy estimand. TRIUMPH-1's 25.0% is the stricter treatment-regimen estimand; its efficacy-estimand counterpart is 28.3%.
  3. Scale. The largest eloralintide Phase 2 arm had 54 participants. Each TRIUMPH-1 arm had roughly 585.
  4. Phase. Phase 2 results often shift in Phase 3. ENLIGHTEN-1 will report at 64 weeks, not 48.

Within those limits, the published data show retatrutide producing more weight loss in its best-performing arms in both its Phase 2 and Phase 3 trials, and eloralintide producing about 20% weight loss at 48 weeks from a single non-incretin pathway. The tolerability profiles differ in kind: eloralintide's leading signals were nausea and fatigue, while retatrutide's were gastrointestinal events (nausea, diarrhea, constipation and vomiting) plus a dysesthesia signal.

Research-market prices: eloralintide vs retatrutide

PeptidePrices tracks research listings for both compounds daily and normalizes prices to a 10 mg standard unit. The lowest price applies any coupon the vendor offers through PeptidePrices.

As of October 21, 2026 Eloralintide Retatrutide
Vendors tracked 10 247
Lowest price per 10 mg $85.00 $20.70
Median price per 10 mg $155.70 $63.99
Vendors publishing COAs 90% 99%
Vendors with an issuer-verified COA on the listing 2 164

The market structure explains the price gap. Retatrutide has 247 competing vendors, and its median 10 mg price is less than half of eloralintide's. Eloralintide has 10, and four of them list only a 5 mg vial. At these figures, the lowest eloralintide listing costs about four times the lowest retatrutide listing per 10 mg.

Certificate evidence is also thinner for eloralintide. Nine in ten of its vendors publish certificates of analysis, but only two had an issuer-verified certificate matched to the exact eloralintide listing on October 21. Check the batch, laboratory and listed strength before relying on any certificate; our COA checker helps verify one against the issuing lab.

The live tables, sorted by price, rating and certificate status, are on the eloralintide price comparison and the retatrutide price comparison.

Frequently asked questions

What is the difference between eloralintide and retatrutide?
Eloralintide is a selective amylin receptor agonist (Lilly code LY3841136). Retatrutide is a triple agonist of the GIP, GLP-1 and glucagon receptors (LY3437943). Both are investigational Eli Lilly obesity drugs given as once-weekly subcutaneous injections in trials, and neither is approved.

Which caused more weight loss in trials, eloralintide or retatrutide?
Retatrutide, in its best-performing arms, though no head-to-head trial exists. Eloralintide produced up to 20.1% mean weight loss at 48 weeks in Phase 2 (efficacy estimand). Retatrutide produced up to 24.2% at 48 weeks in its Phase 2 trial and up to 25.0% at 80 weeks in the Phase 3 TRIUMPH-1 trial (treatment-regimen estimand).

What phase is each drug in?
As of October 21, 2026, eloralintide is in Phase 3: five ENLIGHTEN trials are recruiting, with ENLIGHTEN-1 due to complete its primary phase in March 2028. Retatrutide has peer-reviewed Phase 3 results from TRIUMPH-1 (NEJM) and TRIUMPH-2 (The Lancet), and Lilly has said it plans to file for U.S. approval in the first quarter of 2027.

What were the main side effects?
For eloralintide in Phase 2, nausea and fatigue; nausea ranged from 11% to 64% across arms versus 14% on placebo, and was lower with gradual escalation. For retatrutide's top arm in TRIUMPH-1, Lilly reported nausea in 42.4% versus 14.8% on placebo, dysesthesia in 12.5% versus 0.9%, and adverse-event discontinuation of 11.3% versus 4.9%.

How much do eloralintide and retatrutide cost on PeptidePrices?
As of October 21, 2026, the lowest research-listing price per 10 mg was $85.00 for eloralintide across 10 vendors and $20.70 for retatrutide across 247 vendors, after vendor coupons. Median prices per 10 mg were $155.70 and $63.99. Live prices are on the PeptidePrices eloralintide and retatrutide price pages.

Do eloralintide listings have COAs?
On October 21, 2026, 90% of the 10 eloralintide vendors published certificates of analysis, but only 2 had an issuer-verified certificate matched to the exact eloralintide listing. For retatrutide, 99% of 247 vendors published COAs and 164 had an issuer-verified certificate on the listing.

Has eloralintide been tested together with retatrutide?
No. On October 21, 2026, ClinicalTrials.gov listed no trial that includes both drugs. Lilly is testing eloralintide with GLP-2T (EloraTZP, in the AMPLIFY Phase 3 trials) and in people already taking a weekly incretin (ENLIGHTEN-6).

Continue your research

Sources

Keep researching