Metabolic and Diabetes Peptide Medicines: Insulin, GLP-1, Dual Agonists and Amylin Analogues

What this page covers

Several prescription medicines for diabetes and weight are made of amino acids and act like the body's own hormones. This page sorts them into four groups: insulin and insulin analogues, GLP-1 receptor agonists, the dual GIP and GLP-1 agonist tirzepatide, and the amylin analogue pramlintide. Each is a different molecule with its own approved uses and risks. Having a peptide-type structure does not mean two products share benefits, warnings or indications.

This page gives no amounts, no injection or storage instructions, and no advice to start, stop or switch a medicine. Diabetes care is managed by a clinician. For background on the condition see prediabetes, type 2 diabetes and metabolic syndrome.

Evidence labels: approved medicine means the named regulator has approved the product for the stated use. All label statements below come from the US FDA labels on DailyMed, read 2026-10-22; label dates are given in the sources. Other countries were not checked for most products. Laws and labels change.

The four groups at a glance

Insulin and insulin analogues

Insulin is the body's own blood-sugar hormone. Lantus and Humalog contain lab-made analogues, meaning insulin with a small change to its amino acid chain. The Lantus label says insulin glargine differs from human insulin by one amino acid swap plus two arginines added at one end, and describes it as long-acting. [1] The Humalog label says insulin lispro differs from human insulin at positions B28 and B29 and is rapid-acting. [2] Insulin and its analogues lower blood sugar by helping muscle and fat take up glucose and by reducing glucose release from the liver. [1]

Safety points from the labels:

• Both are contraindicated during an episode of low blood sugar, and in people allergic to the drug or its ingredients. [1][2]


• Low blood sugar is described as the most common adverse reaction to insulins; severe low blood sugar can cause seizures and can be life-threatening. [1]


• Accidental mix-ups among insulin products have been reported, and the label says to check the insulin label each time. [1]


• A change in insulin type, strength, maker or injection site can change blood sugar control. [1]


• Insulins can lower potassium, and the label says potassium should be monitored in people at risk. [1]


• Pens and needles must never be shared between people, even if the needle is changed, because of blood-borne infection risk. [1]


• For Humalog, pump or infusion-set failure can lead rapidly to high blood sugar and ketoacidosis. [2]

"Insulin" on a label is not one product: different insulins act for different lengths of time, and mixes exist. The label-based facts above do not describe any particular person's plan. Insulin-specific details are in insulin and insulin analogues.

GLP-1 receptor agonists

These copy the gut hormone GLP-1. The liraglutide label says it activates the GLP-1 receptor, which increases insulin release when blood sugar is high; the label notes that this release subsides as blood sugar falls. [3] The labels for liraglutide, dulaglutide and semaglutide all carry a boxed warning about thyroid C-cell tumors seen in rodents, with unknown relevance to humans, and are contraindicated with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2. [3][4][5] Full class details, trial results and the brand-versus-molecule table are in the GLP-1 class overview.

Tirzepatide, the dual agonist

Tirzepatide activates both GIP and GLP-1 receptors. [6] In the US it is sold as Mounjaro for type 2 diabetes and as Zepbound for weight and sleep apnea, which are separate approvals. [9] In SURPASS-2, 1,879 adults with type 2 diabetes were randomly assigned for 40 weeks, open-label, to tirzepatide at three study strengths or to a semaglutide comparator; average HbA1c fell by 2.01, 2.24 and 2.30 percentage points with tirzepatide versus 1.86 with semaglutide, and Eli Lilly funded the trial. [10] HbA1c is a lab measure of average blood sugar, not a health outcome such as a heart attack. Evidence label: established for lowering HbA1c in the studied group; the trial's reported outcomes were HbA1c, weight and adverse events, not long-term complications. See semaglutide vs tirzepatide for a fuller comparison.

Pramlintide, the amylin analogue

Amylin is a hormone released with insulin after meals. The Symlin label says pramlintide is an analogue of human amylin that slows gastric emptying and reduces glucagon release after meals, based on non-clinical studies. [7] It carries a boxed warning: used with insulin it raises the risk of severe low blood sugar, especially in type 1 diabetes, usually within 3 hours of an injection. [7] It is contraindicated in people with hypoglycemia unawareness or confirmed gastroparesis, and the label says proper patient selection is critical and the review should include HbA1c, recent blood sugar data and the current insulin plan. [7] The label read here is dated 2019, so a newer version may exist elsewhere. See pramlintide.

Fixed combination: insulin degludec plus liraglutide

Xultophy is one product with two active ingredients. Its label carries the same thyroid C-cell boxed warning as liraglutide, contraindicates use during low blood sugar, and says use with any other liraglutide product or GLP-1 receptor agonist is not recommended. [8] This is why the molecule, the brand and the combination must be kept apart.

What approval does and does not mean here

Approval is specific to a product, a group of people and a use. A GLP-1 weight-loss approval does not make every GLP-1 product, compounded copy or related research peptide approved. See approved, investigational and unapproved peptides and compounded and unapproved GLP-1 products.

Professional-care context

All products here are prescription medicines. Starting, changing or stopping any of them, including insulin, is a decision for the prescriber who knows your history. Review other medicines with them too; see medication interactions and talking with a health professional.