What Is GLP-2? The Gut-Growth Hormone That Is Not GLP-1

Guides · Gut hormones

GLP-2 is a 33-amino-acid gut hormone cut from the same precursor protein as GLP-1 — and almost everything else about it is different. Where GLP-1 became the backbone of modern metabolic medicine, GLP-2 produced exactly one approved drug, for a rare form of intestinal failure, and its job is to make the bowel grow rather than to suppress appetite.

What is GLP-2?

Glucagon-like peptide-2 is a 33-residue peptide released by the L cells of the distal small intestine and colon in response to nutrients arriving in the gut. It was identified in the mid-1980s as a predicted product of the glucagon gene, but it sat unexplained for a decade until 1996, when a Toronto group showed it was the proglucagon-derived peptide responsible for the striking bowel growth seen in certain tumour-bearing mice.

Its defining biological action is trophic: GLP-2 increases villus height and crypt depth, expands the absorptive surface of the small intestine, and improves how much fluid and energy the gut can take up. That single property is what turned it into a drug for short bowel syndrome — and it is also why it carries safety obligations that no appetite hormone does.

One gene, four hormones — and why the names mislead

GLP-2 comes from proglucagon, the product of the GCG gene. The same precursor is processed differently depending on which cell it is made in. In pancreatic alpha cells, prohormone convertase 2 dominates and the main output is glucagon. In intestinal L cells, prohormone convertase 1/3 dominates instead, and the outputs are GLP-1, GLP-2, glicentin and oxyntomodulin.

So GLP-1 and GLP-2 are co-secreted from the same cell, in roughly parallel amounts, after the same meal. That shared origin is the source of most of the confusion online. It does not make them interchangeable: they act on two entirely separate receptors, expressed on entirely different tissues.

One structural detail carries over directly from GLP-1 biology. Native GLP-2 has an alanine at position 2, which makes it a substrate for DPP-4 — the same enzyme that clips GLP-1. Native GLP-2 therefore has a circulating half-life of only about seven minutes. Substituting glycine at position 2 produces a DPP-4-resistant analogue, and that analogue is teduglutide.

How GLP-2 works: a signal that gets relayed

The GLP-2 receptor is a class B G protein-coupled receptor, in the same structural family as the receptors for glucagon, GLP-1, GIP and secretin. The surprising part is where it sits. According to the teduglutide label, GLP2R is found on enteroendocrine cells, subepithelial myofibroblasts and the enteric neurons of the submucosal and myenteric plexus — not on the enterocytes and crypt stem cells that actually proliferate.

The growth signal is therefore indirect. Receptor activation triggers local release of mediators including IGF-1, keratinocyte growth factor and nitric oxide, plus a set of ErbB receptor ligands (amphiregulin, epiregulin and HB-EGF). Two mouse experiments make the case: removing the IGF-1 receptor from intestinal epithelium blocks the response, and a pan-ErbB inhibitor abolishes GLP-2-driven crypt proliferation altogether.

What GLP-2 does in humans

The human data are narrower than the rodent literature but consistent. In adults with short bowel syndrome, dosing across a range of levels produced roughly 750 to 1,000 mL per day of extra intestinal fluid absorption together with measurable increases in villus height and crypt depth. An earlier study using native GLP-2 in eight patients without a colon improved nutrient and energy absorption over 35 days.

Beyond mucosal growth, controlled human infusions show GLP-2 inhibits gastric acid secretion, slows antral emptying (though far more weakly than GLP-1 does), increases mesenteric blood flow in a dose-dependent way, and strengthens epithelial barrier function.

This matters because GLP-2 is increasingly marketed on the coattails of semaglutide and tirzepatide. The shared precursor is real; the shared pharmacology is not.

Teduglutide, and the two analogues that did not make it

Teduglutide (Gattex in the US, Revestive in Europe) is the glycine-2 analogue of GLP-2, molecular weight 3,752 daltons, approved in the US in December 2012 for adults and children aged one year and older with short bowel syndrome who depend on parenteral support. Its terminal half-life is about two hours in healthy subjects and 1.3 hours in patients with short bowel syndrome, and it is cleared largely by the kidney.

The trial history is worth stating plainly, because most summaries skip the first half. The earlier pivotal study did not achieve statistical significance on its prespecified primary endpoint for the high dose; the widely quoted 46%-versus-6% figure comes from a post hoc responder analysis. It was the later STEPS trial that delivered a clean result — 63% of teduglutide patients versus 30% on placebo achieved at least a 20% reduction in weekly parenteral support at both weeks 20 and 24. In the open-label extension, 10 patients came off intravenous nutrition entirely.

Since then, nothing. Glepaglutide received an FDA Complete Response Letter in December 2024 after its once-weekly regimen failed to reach significance. In April 2025, Ironwood disclosed that the FDA required a confirmatory Phase 3 for apraglutide, and that its own analysis found exposure in the completed trial had been lower than planned. As of mid-2026, teduglutide remains the only approved GLP-2 analogue.

Safety: what the label actually requires

A hormone whose function is to make epithelium proliferate carries an obvious concern, and the label addresses it directly. Because of tumour findings in rodent carcinogenicity studies, teduglutide is described as having the potential to cause hyperplastic changes including neoplasia, and colorectal, gastric and small intestinal polyps have been reported. Adults must have a colonoscopy and upper GI endoscopy within six months before starting, a repeat at one year, and then every five years.

The other labelled warnings are intestinal obstruction, biliary and pancreatic disease (with bilirubin, alkaline phosphatase, lipase and amylase monitored at least every six months), fluid overload and congestive heart failure caused by the enhanced absorption itself, and increased absorption of concomitant oral medications — the label records a patient on prazepam who progressed to coma in the first week of treatment.

Frequently asked questions

Is GLP-2 the same thing as GLP-1?

No. They are cut from the same proglucagon precursor in the same intestinal L cells and released together, but they bind different receptors on different tissues. GLP-1 acts on the pancreas, brain and stomach to lower glucose and appetite; GLP-2 acts on cells surrounding the intestinal epithelium to expand absorptive surface.

How long does GLP-2 last in the body?

Native GLP-2 is cleaved by DPP-4 at its position-2 alanine and has a circulating half-life of roughly seven minutes. The glycine-2 analogue teduglutide resists that cleavage and has a terminal half-life of about two hours.

Does GLP-2 help with leaky gut or general digestion?

The barrier-function work is largely preclinical, and the human absorption data come from patients with surgically shortened bowel. There is no controlled human evidence that GLP-2 improves digestion or intestinal permeability in otherwise healthy people, and no approved use outside short bowel syndrome.

Why do the newer GLP-2 analogues keep failing?

For different reasons in each case. Glepaglutide’s once-weekly regimen missed statistical significance while the twice-weekly arm did not, and the FDA asked for another trial. Apraglutide’s sponsor found that the dose actually delivered in its Phase 3 was lower than intended. Neither outcome says the biology is wrong — both say the dosing and trial design are hard.

Informational only — not medical advice · 21+. Nothing here is a recommendation to obtain or use any peptide. Teduglutide is a prescription medicine with mandatory endoscopic surveillance requirements; decisions about it belong with a qualified healthcare professional.