No — Ozempic, Mounjaro, Wegovy, Zepbound and the other GLP-1 drugs are not insulin. They copy a different hormone, made in a different organ, and they lower blood glucose by a different route: they prompt the pancreas to release more of its own insulin, and only when glucose is high. Insulin lowers glucose directly, whatever the level. That difference is why the two behave differently on their own and why the labels warn about using them together.
This page sets out the two hormones from the protein registers, the mechanism from the current labels, and what the labels report when a GLP-1 drug is added to insulin. All sources were read on 3 October 2026.
Two different hormones
| Insulin | GLP-1 | |
|---|---|---|
| Made by | Beta cells of the pancreas | Enteroendocrine L cells throughout the gut (also some brain neurons) |
| Structure | Two chains: B chain 30 amino acids, A chain 21 — 51 in all | One chain: 30 or 31 amino acids |
| Made from | Proinsulin (110 amino acids) | Proglucagon (180), which also yields glucagon and GLP-2 |
| What it does to glucose | Lowers it directly | Increases insulin release and lowers glucagon release when glucose is high |
| Drug versions | Many insulins (glargine, degludec, lispro and others) | Semaglutide, liraglutide, dulaglutide, exenatide; tirzepatide acts on GLP-1 and GIP receptors |
Structure and source: UniProt P01308 (insulin) and P01275 (proglucagon), read 3 October 2026. Mechanism: Ozempic prescribing information, section 12.1.
The two do share one thing that adds to the confusion: both are peptides — chains of amino acids — and so both are injected, because a peptide swallowed is mostly digested. Whether a GLP-1 drug counts as a peptide at all is less simple than it sounds, and is covered on is GLP-1 a peptide?. The tablet forms of semaglutide get around digestion with an absorption enhancer, which is on oral GLP-1s.
What a GLP-1 drug does instead
Ozempic's label puts it in one sentence: semaglutide "reduces blood glucose through a mechanism where it stimulates insulin secretion and lowers glucagon secretion, both in a glucose-dependent manner. Thus, when blood glucose is high, insulin secretion is stimulated, and glucagon secretion is inhibited." The label adds a minor delay in stomach emptying after meals.
The phrase that matters is glucose-dependent. The drug amplifies the body's own response to high glucose rather than adding insulin regardless of need, which is why the label can also report that, with semaglutide, the insulin secretion rate in people with type 2 diabetes was similar to that of healthy subjects. It also means the drug relies on beta cells that can still make insulin. The fuller mechanism, appetite included, is on how GLP-1 works, and the second hormone in Mounjaro and Zepbound is on GIP and GLP-1.
What the labels show when the two are combined
Because a GLP-1 drug's action fades as glucose falls, it causes little hypoglycaemia by itself. Insulin has no such brake. Ozempic's label reports both situations from its placebo-controlled trials:
| 30-week trial | Placebo | Ozempic 0.5 mg arm | Ozempic 1 mg arm |
|---|---|---|---|
| Alone (monotherapy) — documented symptomatic hypoglycaemia, ≤70 mg/dL | 0% | 1.6% | 3.8% |
| Alone — severe, or confirmed ≤56 mg/dL | 1.6% | 0% | 0% |
| Added to basal insulin — documented symptomatic hypoglycaemia, ≤70 mg/dL | 15.2% | 16.7% | 29.8% |
| Added to basal insulin — severe, or confirmed ≤56 mg/dL | 5.3% | 8.3% | 10.7% |
| Added to basal insulin — severe (needing another person's help) | 0% | 0% | 1.5% |
Ozempic prescribing information, Table 2. The arms are the trials' fixed doses, reported as the label reports them; this is not a dosing table.
Read across a row and the pattern is plain. On its own, Ozempic's hypoglycaemia rate was in single figures and the most serious category was no higher than placebo's. Added to insulin, every rate rose — including in the placebo group, because the insulin was still there — and the 1 mg arm roughly doubled the placebo-with-insulin figure for documented episodes (29.8% vs 15.2%). (Comparison across the label's rows; glp1ledger reading.)
The trial itself had already allowed for this: people whose HbA1c was 8.0% or below at screening reduced their insulin dose by 20% at the start "to reduce the risk of hypoglycemia". The warning section of the label says the same thing in general terms — use with insulin or a sulfonylurea "may have an increased risk of hypoglycemia, including severe hypoglycemia", and the risk "may be lowered by a reduction in the dose" of the insulin. Any such change is the prescriber's to make.
The two products that are both
There is one place where the answer to "is it insulin?" is partly yes. Two US products put an insulin and a GLP-1 receptor agonist into the same pen:
| Product | Insulin | GLP-1 receptor agonist | Maker | Approved |
|---|---|---|---|---|
| Soliqua 100/33 | Insulin glargine | Lixisenatide | Sanofi | 21 November 2016 |
| Xultophy 100/3.6 | Insulin degludec | Liraglutide | Novo Nordisk | 21 November 2016 |
Drugs@FDA, BLA 208673 and BLA 208583, read 3 October 2026; both listed as prescription products. Soliqua's current label (effective 2026-03-18) is indicated for glycaemic control in adults with type 2 diabetes and states that use "with any other product containing a GLP-1 receptor agonist is not recommended".
These are fixed-ratio combinations: each dial of the pen delivers both drugs in a set proportion. Both labels are for glycaemic control in adults with type 2 diabetes; neither is approved for weight management. Ozempic, Mounjaro, Wegovy and Zepbound contain no insulin. The full register of what is and is not a GLP-1 is on which drugs are GLP-1s.
Type 1 diabetes, and a line that left the label
Insulin is essential in type 1 diabetes, where the beta cells no longer make it. A GLP-1 drug, which works through those cells, is not a substitute, and no GLP-1 drug is approved for type 1 diabetes — every brand's indications are for type 2 diabetes, weight management or conditions linked to them.
The labels used to say so in as many words. Ozempic's first label, in December 2017, carried a Limitations of Use line: "Not indicated for use in type 1 diabetes mellitus or treatment of diabetic ketoacidosis." The current Ozempic label has no Limitations of Use section, and the phrase "type 1 diabetes" does not appear in it. The same is true of the current Mounjaro, Trulicity and Rybelsus labels. Of the eight current GLP-1 labels read for this page, only Wegovy's mentions type 1 diabetes, to say that use "in patients with type 1 diabetes mellitus or in combination with insulin has not been evaluated". (glp1ledger search of the eight manufacturer labels on DailyMed, 3 October 2026.)
The removal does not widen anything. An indication is what a label says a drug is for, and type 1 diabetes is not among them; the missing sentence is a change in how labels are written, not a new use. Which supplement removed it is not stated in the approval letters read for this page, so this page does not date it.
What this page does not cover
It does not cover whether anyone should add, reduce or stop insulin, or switch between treatments — those are decisions for the prescriber. It reports what the protein registers and the labels state. The molecule itself is described in Peptide Lexicon's semaglutide entry, and what a GLP-1 is, in general, on what is a GLP-1?.
Sources
- UniProt, P01308 (Insulin, human) — chain positions, tissue specificity, function, rest.uniprot.org, read 3 October 2026.
- UniProt, P01275 (Pro-glucagon, human) — GLP-1(7-36) and GLP-1(7-37) positions, tissue specificity, rest.uniprot.org, read 3 October 2026.
- Novo Nordisk, OZEMPIC (semaglutide) injection, prescribing information, DailyMed set ID adec4fd2-6858-4c99-91d4-531f5f2a2d79, effective 2026-06-01 — sections 5, 6.1 (Table 2), 12.1, 12.2, 14.1, dailymed.nlm.nih.gov, read 3 October 2026.
- Novo Nordisk, OZEMPIC prescribing information as approved 12/2017, accessdata.fda.gov, read 3 October 2026.
- Novo Nordisk, WEGOVY prescribing information, DailyMed set ID ee06186f-2aa3-4990-a760-757579d8f77b, effective 2026-06-18, dailymed.nlm.nih.gov; Mounjaro (set ID d2d7da5d-…, effective 2026-08-27), Trulicity (463050bd-…, 2026-06-16), Rybelsus/Ozempic tablets (27f15fac-…, 2026-01-30), Zepbound, Foundayo and Saxenda, all on DailyMed, read 3 October 2026.
- Novo Nordisk, XULTOPHY 100/3.6 prescribing information, effective 2025-10-14 — indication (type 2 diabetes), via open.fda.gov, read 3 October 2026.
- Sanofi-Aventis U.S., SOLIQUA 100/33 prescribing information, effective 2026-03-18, via open.fda.gov, read 3 October 2026.
- US Food and Drug Administration, Drugs@FDA records for BLA 208673 (Soliqua 100/33) and BLA 208583 (Xultophy 100/3.6), via open.fda.gov, read 3 October 2026.