Where to Inject Semaglutide: Sites, Pens and Units

"Where to inject semaglutide" is answered in one line by both labels: abdomen, thigh or upper arm. What makes the search worth a page is what surrounds that line — two products from one maker with different missed-dose rules, pens that deliver different volumes for the same molecule, and the vial-and-syringe case the labels do not cover at all. This page reports the Ozempic and Wegovy labels (read 2026-10-02) side by side and converts the doses to syringe units. It describes what the labels say; it gives no instruction.

General subcutaneous technique for any peptide — needle length, angle, the nursing references — is on the peptide injection guide; the tirzepatide equivalent of this page is where to inject tirzepatide, and its labels differ in ways listed below. The dose ladders themselves are on the semaglutide dosage page.

The sites, as the two labels name them

One small difference from tirzepatide is worth noticing. The Zepbound and Mounjaro labels reserve the back of the upper arm for an injection given by another person; the semaglutide labels list the upper arm without that qualifier. Neither family ranks its sites — both state similar exposure at all three — so a page claiming that "the stomach works faster" for semaglutide is reporting something the label contradicts.

Rotation is written as a rule about spots within a region rather than about regions: the Ozempic label directs a different injection site each week when the same body region is used. Its one further site rule concerns insulin — separate injections, never mixed, the same region allowed but not adjacent spots.

Timing and missed-dose rules: where Ozempic and Wegovy differ

The two products share a molecule, a half-life and a maker, so the difference is in how the rule is written rather than in the pharmacology. Five days after a missed Ozempic dose and "more than 2 days before the next" for Wegovy describe the same window from opposite ends of a seven-day week. The Wegovy rule on consecutive missed doses is new to its 2026 label and has no Ozempic counterpart in the text read. Why a weekly molecule tolerates these windows — maximum concentration 1 to 3 days after the dose, half-life about one week, still in the circulation about 5 weeks after the last dose on the Ozempic label and 5 to 7 weeks on Wegovy's — is set out on the semaglutide half-life page.

What each pen delivers

The pens are dialled in milligrams; the volume is set by the pen's concentration. From the label strengths:

So a Wegovy maintenance injection is three-quarters of a millilitre, half again the volume of a Zepbound single-dose pen (0.5 mL). How the Ozempic dial counts clicks — and why counting them to split a dose is unsupported by the label — is on Ozempic pen clicks. The general conversion from milligrams to volume is on mg to mL.

The label doses in units, research vials

Semaglutide doses are small, so on a research vial the question is less whether the dose fits and more whether it can be read. Units on a U-100 syringe = mg ÷ mg/mL × 100. A 5 mg vial with 2 mL is 2.5 mg/mL; with 1 mL, 5 mg/mL; a 10 mg vial with 1 mL, 10 mg/mL. Water volumes per vial size are on semaglutide reconstitution.

At 10 mg/mL the first step is 2.5 units — a quarter of the way between two marks on most 100-unit barrels, which is why the FDA's 2024 bulletin on compounded semaglutide encouraged prescribers and compounders to provide "the appropriate syringe size for the intended dose". That bulletin's record of patients drawing five to 20 times the intended amount, and the unit confusion behind it, is summarised on the semaglutide dosage page. The milligram-to-units conversion sets out the formula, reading an insulin syringe the marks, and the calculator's semaglutide setting any vial.

What is not established

The labels describe the approved solutions in their pens. No label covers a lyophilised research vial of semaglutide, and the site and exposure statements above come from the approved product. Compounded vials, including those with added B12 or glycine, are a separate case set out on semaglutide or tirzepatide with B12. Storage and the general mixing procedure are covered on Medibact's how to store peptides and how to reconstitute peptides pages, and the compound itself in Medibact's Semaglutide guide. Nothing on this page is an instruction; technique and dose belong with the prescriber.

Sources and dates

Opened 2026-10-02: the OZEMPIC injection label via openFDA (Novo Nordisk, effective 2026-07-30) — section 2.1 (administration, missed dose, day change, insulin), section 3 (strengths) and section 12.3 (pharmacokinetics); the WEGOVY injection and tablet label via DailyMed (set id ee06186f-2aa3-4990-a760-757579d8f77b, effective 2026-06-18) — sections 2, 3 and 12.3; the ZEPBOUND and MOUNJARO labels via openFDA for the comparison of site wording; the FDA MedWatch bulletin of 2024-07-29 on dosing errors with compounded semaglutide. Volumes and units are arithmetic by this site. Corrections go to the contact page.