Is oxyntomodulin the same as glucagon?

No, but it contains the glucagon sequence plus an eight-residue C-terminal extension, which is why it retains glucagon receptor activity.

Is oxyntomodulin available as a medicine?

No. Its short half-life and modest potency at each receptor mean engineered analogues were developed instead.

Why do GLP-1 and glucagon agonism combine usefully?

Glucagon increases energy expenditure and hepatic lipid oxidation; sufficient GLP-1 signalling offsets its glucose-raising effect. Oxyntomodulin shows the body already uses this combination.

GLP-1 & Incretin Science

What Is Oxyntomodulin? Nature's Dual Agonist

JMWritten & reviewed by Jack Muncaster · Founder, UK PeptidesLast reviewed 2026-08-233 cited sources

Oxyntomodulin is a naturally occurring 37-residue gut peptide produced from proglucagon that activates both the GLP-1 and glucagon receptors. It is the endogenous proof that combined GLP-1 and glucagon agonism is physiologically coherent, and the precedent behind survodutide and mazdutide.

Key facts

Type: Endogenous gut peptide
Length: 37 residues
Molecular weight: ~4,422 Da
Molecular formula: C192H295N59O60S
PubChem CID: 16144019
Precursor: Proglucagon
Receptors: GLP-1R and glucagon receptor
Drugs built on it: Survodutide, mazdutide

Where it comes from

Oxyntomodulin is produced by post-translational processing of proglucagon in intestinal L cells — the same precursor protein that yields GLP-1. Which peptides emerge depends on which processing enzymes are present, which is why the pancreas and the intestine generate different products from identical genetic material. Oxyntomodulin is released after meals alongside GLP-1.

Why it activates two receptors

Its sequence contains the full glucagon sequence with an eight-residue C-terminal extension. That shared ancestry means it retains meaningful affinity for the glucagon receptor while also engaging GLP-1R, though with lower potency at each than the dedicated ligands. It is not a strong agonist at either — it is a moderate agonist at both.

Why that combination is interesting rather than contradictory

Glucagon raises blood glucose, so pairing it with GLP-1 looks self-defeating. Physiologically it is not: glucagon also increases energy expenditure and drives hepatic lipid oxidation, and sufficient concurrent GLP-1 signalling offsets the glycaemic effect. Oxyntomodulin demonstrates that the body itself deploys this combination, which is the strongest possible argument that the pharmacology is coherent.

What was built on it

Survodutide and mazdutide are engineered GLP-1/glucagon dual agonists, with mazdutide derived from oxyntomodulin directly. Retatrutide extends the same logic by adding GIP on top, making a triple agonist. Every glucagon-containing incretin drug traces its rationale to this peptide.

Why oxyntomodulin itself is not a drug

It has a very short half-life, being subject to DPP-4 and rapid clearance like other native gut peptides, and its potency at each receptor is modest. Engineering was required on both counts — protease resistance and albumin binding for duration, and sequence optimisation to tune the balance of activity between the two receptors deliberately rather than accepting what physiology provides.

Extended research context

The GLP-1 & Incretin Science deep dive

Deep dive: the two routes to a bigger effect

Every compound trying to beat GLP-1 alone has taken one of two routes. The first adds more receptors from the same hormone family — GIP in tirzepatide, GIP and glucagon in retatrutide. The second adds a non-incretin satiety hormone, which in practice means amylin: CagriSema combines cagrilintide with semaglutide, and amycretin engages both receptors from one molecule. Both routes work, because they recruit signalling pathways that do not fully overlap. Neither has escaped the constraint that binds all of them, which is that gastrointestinal tolerability worsens as effect size grows.

Deep dive: why a percentage is not a result

The most-quoted numbers in this field are the least comparable. REDEFINE 1 reported 22.7% and 20.4% for the same compound in the same trial — the first among participants who adhered to treatment, the second across everyone randomised. TRIUMPH-1 reported 28.3% in an uncomplicated obesity population while TRIUMPH-3 reported up to 22.6% in adults with established cardiovascular disease, using the same compound. Before any two figures can be compared they have to match on estimand, population, duration, comparator and whether the number is placebo-adjusted. Most published comparisons match on none of them.

Deep dive: what happens after the trial stops

Every headline figure describes weight while treatment continues. The STEP-1 extension found that a year after semaglutide was stopped, participants had given back roughly two-thirds of what they lost, moving from 17.3% mean reduction to a net 5.6% — though average weight remained below baseline and nearly half stayed at least 5% down. Meta-analysis puts regain at around 0.8 kg per month. This is why maintenance studies such as TRIUMPH-6 matter more to the field's future than another two points of peak reduction.

Research applications

▸Comparing incretin and amylin compounds on a like-for-like basis
▸Interpreting estimands, thresholds and placebo-adjusted figures in trial reports
▸Tracking the obesity pipeline across sponsors and jurisdictions
▸Understanding receptor pharmacology behind GLP-1, GIP, glucagon and amylin
▸Distinguishing licensed medicines from investigational compounds

Handling checklist

✓Identify which estimand a quoted percentage comes from before citing it
✓Check the trial population and baseline BMI against the comparison you are making
✓Confirm the duration and whether the reduction curve had plateaued
✓Read discontinuation rates alongside efficacy figures
✓Verify every NCT identifier against ClinicalTrials.gov rather than secondary reporting

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Comparing headline percentages across different trials

Fix: Population, duration, estimand and comparator all differ; the numbers are not interchangeable.

✗ Quoting the larger of two figures from the same trial

Fix: Name the estimand. Efficacy and treatment-policy answer different questions.

✗ Treating peak reduction as a durable outcome

Fix: Substantial regain follows cessation across the class; peak figures describe a maintained state.

✗ Assuming an oral route means a weaker mechanism

Fix: Route and receptor count are independent. Orforglipron is weaker because it hits one receptor, not because it is a tablet.

✗ Reading investigational compounds as available treatments

Fix: Most of this pipeline holds no authorisation anywhere; mazdutide is approved only in China.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Frequently asked questions

Is oxyntomodulin the same as glucagon?: No, but it contains the glucagon sequence plus an eight-residue C-terminal extension, which is why it retains glucagon receptor activity.
Is oxyntomodulin available as a medicine?: No. Its short half-life and modest potency at each receptor mean engineered analogues were developed instead.
Why do GLP-1 and glucagon agonism combine usefully?: Glucagon increases energy expenditure and hepatic lipid oxidation; sufficient GLP-1 signalling offsets its glucose-raising effect. Oxyntomodulin shows the body already uses this combination.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

Written and reviewed by

Jack Muncaster · Founder, UK Peptides

Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.

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