# Glucagon > Insulin’s counter-hormone — a 29-amino-acid peptide that raises blood glucose, the emergency rescue for severe lows, and the "G" in the new triple agonists. - Also known as: GlucaGen, Baqsimi, Gvoke - Class: Metabolic - FDA approved: Yes - Canonical page: https://www.americanpeptide.com/catalog/glucagon ## Overview Glucagon is the metabolic mirror image of insulin. Released by the pancreatic alpha cells when blood sugar falls, this 29-amino-acid peptide tells the liver to break down glycogen and make new glucose, pushing blood sugar back up. It is the body’s primary defense against hypoglycemia, the basis of emergency rescue products, and — in a development that has put it back at the center of metabolic drug design — one of the three receptors the newest weight-loss agonists deliberately engage. Glucagon and insulin are a push-pull pair: insulin lowers blood glucose, glucagon raises it, and health depends on their balance. When blood sugar drops dangerously — most often in insulin-treated diabetes — glucagon is the rescue, which is why it is sold as emergency kits: the classic reconstituted injection (GlucaGen), a nasal powder (Baqsimi, 2019), and a ready-to-use autoinjector (Gvoke). It is also used in radiology and endoscopy to relax smooth muscle. As a molecule it is a 29-residue peptide derived from the same precursor (preproglucagon) that gives rise to GLP-1 and GLP-2 — a family relationship that matters more than it first appears. For decades glucagon was framed only as the hormone you suppress in diabetes. The reframing came from drug design: adding glucagon-receptor agonism to incretin drugs increases energy expenditure and fat mobilization, and the glucagon receptor is the "G" in the GIP/GLP-1/glucagon triple agonists (such as retatrutide) now posting the largest weight-loss numbers in trials. That is the forward-looking turn — the same hormone that, unopposed, worsens diabetic hyperglycemia becomes, when balanced against incretin signaling, a lever for greater fat loss and metabolic rate. It is a clean example of how a "bad" hormone in one context is a deliberate design ingredient in another. ## Mechanism Binds the glucagon receptor on hepatocytes, raising cAMP and driving glycogenolysis and gluconeogenesis to increase blood glucose. It opposes insulin in the moment-to-moment regulation of blood sugar. ## Chemistry | Property | Value | | --- | --- | | Molecular formula | C153H225N43O49S | | Molecular weight | 3485 Da | | CAS number | 16941-32-5 | ## Sequence ``` HSQGTFTSDYSKYLDSRRAQDFVQWLMNT ``` ## Research areas Studied in: Severe hypoglycemia, Glucose counter-regulation, Triple-agonist metabolic drugs. Guides on this site: - [Weight Loss & Metabolic Health](https://www.americanpeptide.com/research-areas/weight-loss): Incretin and metabolic peptides studied for glycemic control and fat loss. ## Key research - Severe hypoglycemia rescue — the approved use; raises blood glucose fast via hepatic glycogenolysis. - Insulin counter-regulation — the opposing arm of moment-to-moment glucose control. - Triple-agonist drugs — glucagon-receptor agonism is the "G" in GIP/GLP-1/glucagon agonists studied for large weight loss. - Procedural use — relaxes GI smooth muscle for imaging and endoscopy. - Preproglucagon family — shares a precursor with GLP-1 and GLP-2. ## Storage, handling & synthesis **Storage.** Older glucagon kits are stored as lyophilized powder + diluent and reconstituted immediately before use; ready-to-use and nasal products follow their own label storage. The peptide is unstable in solution and is not kept reconstituted. **Handling.** Reconstituted glucagon should be used promptly — it can aggregate/fibrillate in solution. Emergency products are designed for immediate single use. **Synthesis.** Glucagon is a 29-residue peptide produced by chemical synthesis or recombinant expression. It is prone to aggregation and fibrillation in aqueous solution, which is why traditional products are lyophilized and reconstituted at the point of use, and why newer formulations engineered for ready-to-use stability were a meaningful advance. ## FAQs ### What does glucagon do? Glucagon raises blood sugar — it is the counter-hormone to insulin. The pancreas releases it when glucose falls, signaling the liver to release stored glucose. As a drug it is the emergency rescue for severe hypoglycemia. ### Why is glucagon in weight-loss drugs? Glucagon-receptor agonism increases energy expenditure and fat mobilization. It is the "G" in the GIP/GLP-1/glucagon triple agonists (like retatrutide) that show the largest weight-loss effects in trials. ### How is it related to GLP-1? Both come from the same precursor protein, preproglucagon. Glucagon raises blood sugar; GLP-1 lowers it and curbs appetite — different products of one parent molecule. ### Is this medical advice? No — this is a research and educational reference, not dosing guidance. ## Latest research Recent trials and publications mentioning Glucagon, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [Tirzepatide's Role in Postmenopausal HR+ Breast Cancer Survivors](https://clinicaltrials.gov/study/NCT07257484) — RECRUITING · PHASE4 · NCT07257484 - [A Study to Evaluate the Effect of Maridebart Cafraglutide on Insulin Sensitivity and β-cell Function in Participants With Type 2 Diabetes Mellitus](https://clinicaltrials.gov/study/NCT07160257) — ACTIVE_NOT_RECRUITING · PHASE1 · NCT07160257 - [Tirzepatide to Reduce rEcurrence And Burden After Ablation of Atrial Fibrillation](https://clinicaltrials.gov/study/NCT07382024) — NOT_YET_RECRUITING · NA · NCT07382024 - [A Study to Evaluate ALN-2232 in Participants With Obesity](https://clinicaltrials.gov/study/NCT07463846) — RECRUITING · PHASE1, PHASE2 · NCT07463846 - [A Study to Investigate Effectiveness of Tirzepatide Following Initiation of Ixekizumab in Participants With Active Psoriatic Arthritis and Overweight or Obesity in Clinical Practice (TOGETHER AMPLIFY-PsA)](https://clinicaltrials.gov/study/NCT06864026) — RECRUITING · PHASE4 · NCT06864026 - [Acute Microbial Switch](https://clinicaltrials.gov/study/NCT05764200) — COMPLETED · NA · NCT05764200 --- Source: AmericanPeptide.com — https://www.americanpeptide.com/catalog/glucagon Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.