Exendin 9-39 — developed as avexitide — is the inverse of the incretin story. Where semaglutide and tirzepatide activate the GLP-1 receptor, avexitide occupies it without triggering signalling. It is a truncated fragment of exendin-4, the same peptide scaffold that gave rise to exenatide, engineered to block the receptor rather than switch it on.
The rationale is mechanistic. In post-bariatric hypoglycaemia (PBH), an exaggerated postprandial GLP-1 response drives excessive insulin secretion, producing recurrent hypoglycaemic events. A competitive GLP-1 receptor antagonist is designed to blunt that GLP-1-driven insulin response at the pancreatic islet beta cell. The same mechanism has been explored in congenital hyperinsulinism, where insulin secretion is dysregulated by other routes.
Evidence. The published record is trial-stage, not licensed practice, and should be read as such. Two Phase 2 PBH trials reported statistically significant reductions in hypoglycaemic events. The PREVENT crossover trial (2021) reported reduced postprandial hyperinsulinaemia and neuroglycopenic symptoms under experimental conditions. A Phase 3 programme, LUCIDITY, reported positive topline results in participants with PBH following Roux-en-Y gastric bypass. Positive topline results are an early disclosure; the full peer-reviewed dataset is what would carry weight.
UK status. There is no MHRA marketing authorisation and no UK licence for avexitide. Under the Medicines Act 1968 and the Human Medicines Regulations 2012 it is an unlicensed investigational compound in the UK. In the US the regulator has granted it Breakthrough Therapy Designation for PBH and congenital hyperinsulinism — a designation that expedites review, not an authorisation, and one that has no effect on UK supply. Framing it as a licensed medicine in the UK would be wrong; framing the entire class by its agonists alone would miss the pharmacology.
Research use only. Nothing here is consumption or dosing guidance.
This article is AI-researched and editorially reviewed. It is provided for research and educational purposes only and is not medical advice. Research peptides are not licensed for human consumption in the UK.