Oxyntomodulin

Oxyntomodulin is produced by intestinal L-cells from proglucagon and consists of the full glucagon sequence plus an eight-amino-acid C-terminal extension. It binds both GLPR and GCGR with relatively low affinity - roughly 10 to 100-fold weaker than the native ligands at their own receptors - but the dual action is what matters: appetite suppression from the GLP-1 arm and increased energy expenditure and hepatic fat oxidation from the glucagon arm. Human infusion studies in the mid-2000s showed both reduced food intake and, unusually, increased activity-related energy expenditure, which established the principle that a dual agonist could lose weight from both sides of the energy balance equation. Its native form is useless as a drug because DPP-4 destroys it within minutes; every dual agonist in this class is an attempt to make oxyntomodulin last.

Targets: GLP-1 receptor, Glucagon receptor

• · The classic Imperial College studies dosed 400 nmol/kg subcutaneously three times daily for four weeks, producing about 2.3 kg weight loss. That is a body-weight-scaled molar dose, not a fixed milligram figure, and no standardised mass-based protocol exists.

Work out your exact syringe units →

• commonNausea— Milder than modern analogues because exposure is so brief.
• commonInjection-site reaction— Three injections a day.
• uncommonIncreased heart rate— Glucagon-arm effect.

• Pregnancy.
• Phaeochromocytoma or insulinoma - glucagon-receptor caution.
• No modern safety database exists; human exposure has been limited to small short trials.

• redundantsurvodutide — Survodutide is essentially a stabilised, weekly version of this molecule.
• redundantmazdutide — Mazdutide is a lipidated oxyntomodulin analogue.

• · Weight.
• · Heart rate.
• · Glucose.

Not approved anywhere; sold as a research chemical.

• Wynne et al. 2005, subcutaneous oxyntomodulin reduces body weight in overweight and obese subjects, Diabetes (trial)
• Wynne et al. 2006, oxyntomodulin increases energy expenditure, International Journal of Obesity (trial)

Oxyntomodulin is the natural experiment that created the dual-agonist class. It is glucagon with eight extra residues on the end, and that extension shifts its receptor profile so that it activates both GCGR and GLP1R - weakly at both, but at both. The Imperial College group's human studies in the mid-2000s showed that subcutaneous oxyntomodulin three times daily reduced food intake, increased energy expenditure and produced about 2.3 kg of weight loss over four weeks, and critically that it did both sides of the energy balance equation rather than only suppressing intake. That result is the direct intellectual origin of cotadutide, survodutide, mazdutide, pemvidutide, efinopegdutide and the glucagon arm of retatrutide. The reason oxyntomodulin itself never became a drug is entirely pharmacokinetic: a 12-minute half-life requires three injections a day for a fraction of the effect that a weekly engineered analogue delivers, and its receptor potency is low enough that large doses are needed. There is a genuinely important point here for anyone buying research-grade oxyntomodulin: this is not a novel or exotic compound that the pharmaceutical industry overlooked. It is the weak, short-acting prototype of drugs that now exist in dramatically better form, and choosing it over a modern dual agonist is choosing the version that failed.

The main failure is expectation. People buy research-grade oxyntomodulin because the mechanism sounds sophisticated - a natural dual agonist that raises energy expenditure - and then discover that three injections a day produces about 2.3 kg over a month. That is what the published data says, and it is the honest number. The second issue is that it is a research chemical with no identity verification, and a 37-residue peptide is not something you can confirm at home.

• GLP-1 receptor (GLP1R) — Roughly two orders of magnitude weaker than native GLP-1, commonly cited but not re-verified here

  Satiety, delayed gastric emptying and glucose-dependent insulin secretion, at a magnitude limited by the low potency and 12-minute half-life.

• Glucagon receptor (GCGR) — Weaker than native glucagon

  Increased energy expenditure and hepatic fatty-acid oxidation. This is the arm that made oxyntomodulin interesting - it demonstrated in humans that a glucagon component could raise energy expenditure without causing hyperglycaemia when paired with GLP-1 activity.

• Subcutaneous oxyntomodulin in overweight and obese subjects Randomised controlled human study · n=26 · 4 weeks · 2005

  Mean weight loss of 2.3 kg over four weeks with three-times-daily subcutaneous oxyntomodulin versus 0.5 kg with placebo.

• Oxyntomodulin and energy expenditure Randomised controlled human study · n=15 · 1 weeks · 2006

  Increased activity-related energy expenditure in addition to reduced energy intake - the finding that made the glucagon arm worth engineering into drugs.

Acute effects on appetite within the hour of an injection or infusion. Effects last a few hours at most. Cumulative weight effects over four weeks in the published studies, at about 2.3 kg.

There is no good reason to stack oxyntomodulin with anything. It contains a weak GLP-1 arm, so it is redundant with every incretin, and its glucagon arm is too weak and too short-acting to add anything to a proper dual agonist. If the appeal is the glucagon mechanism, survodutide, mazdutide, pemvidutide and retatrutide all deliver it with a week-long half-life and actual trial data.

Against survodutide, mazdutide, pemvidutide and efinopegdutide: they are all engineered oxyntomodulin descendants with week-long half-lives, and every one of them is dramatically more effective. Against semaglutide: not remotely comparable - 2.3 kg over four weeks versus 15% over 68. The value of oxyntomodulin is entirely historical and mechanistic. It is the compound that proved glucagon agonism could add energy expenditure to appetite suppression in humans, and that proof is why the modern dual agonists exist.

$50–$200/month. Research chemical pricing, and three injections a day makes the effective cost higher than the vial price suggests. Market observation, not verified pricing.

• ?Receptor affinity values relative to native GLP-1 and glucagon are commonly cited but were not verified in this session.
• ?The sequence given is the standard published oxyntomodulin sequence and was not verified against a primary structural source.
• ?Participant numbers for the two Wynne studies are as commonly reported and were not individually re-verified against the papers.
• ?There is no pharmacokinetic package because there was never a product.
• ?Cost figures are market observations, not verified pricing.

• Subcutaneous oxyntomodulin reduces body weight in overweight and obese subjects: a double-blind, randomized, controlled trial Wynne K et al., Diabetes, 2005 · PMID 16046306

  The four-week weight-loss study. This is essentially the entire human efficacy evidence base for oxyntomodulin itself.

• Oxyntomodulin increases energy expenditure in addition to decreasing energy intake in overweight and obese humans: a randomised controlled trial Wynne K et al., Int J Obes (Lond), 2006 · PMID 16619056

  The energy expenditure finding that justified building the entire GLP-1/glucagon dual agonist class.