GLP-1 Injection Guide: Sites, Technique, and Pen Instructions by Brand

Every FDA-approved GLP-1 — Ozempic, Wegovy, Mounjaro, and Zepbound — is injected the same basic way: subcutaneously, once weekly, with a prefilled pen. The mechanics are simple once you've done it a few times, but the questions people actually have (where exactly, how to rotate, what if I'm nervous about needles) deserve a straight answer pulled from the label rather than a forum guess. This guide covers technique for all four brands and applies the same way to a compounded version of either molecule.

Approved injection sites

All four labels approve the same three general locations: the abdomen, the thigh, or the upper arm¹²³⁴. If someone else is giving you the injection, the back of the upper arm is the site used for that; self-injection is typically done in the abdomen or thigh, which are easier to reach and see. The abdomen is the most commonly chosen site because it's flat, accessible, and has a consistent fat layer, but all three approved sites work equally well pharmacologically — pick whichever is easiest for you to reach comfortably and consistently.

Rotate your site every time

Every label instructs rotating the injection site with each dose, and using a different spot within the same body region week to week if you keep injecting in that region¹²³⁴. Rotation matters for two practical reasons: it reduces the buildup of local irritation, redness, or small lumps (lipohypertrophy) that repeated injections in the exact same spot can cause, and it keeps absorption consistent. A simple system — abdomen this week, thigh next week, other side of the abdomen the week after — is easier to stick to than trying to remember an exact spot from a month ago. Some people keep a small note or a rotation chart on their phone for the first few months.

How to actually give the injection

The core steps are the same across all four pens, though exact device mechanics differ slightly by brand (some are single-dose disposable pens, others require a twist-and-click dose selection) — always follow the specific instructions-for-use booklet that ships with your prescription:

Wash your hands and let the pen come to room temperature if it's been refrigerated (cold medication can sting more).

Clean the injection site with an alcohol swab and let it air-dry — injecting through wet alcohol can sting.

Pinch a fold of skin if instructed by your specific pen's instructions (not all require it), insert the needle at the angle your device specifies, and press to deliver the full dose — most pens have an audible click or a window that confirms a complete dose.

Don't rub the site afterward; a light press with a clean cotton ball or tissue is enough if there's a drop of blood.

Dispose of the needle in a sharps container, never loose in household trash.

Common technique questions

A little bruising, redness, or a small bump at the injection site is common and usually resolves in a few days — see our side effects guide for when a reaction is worth calling your provider about instead of waiting out. If you're switching between the brand-name pen and a compounded vial-and-syringe version of the same molecule, the injection sites and rotation principle are identical; only the device mechanics change, and a good telehealth provider will walk you through the specific technique for what they dispense as part of your onboarding — worth weighing when you compare providers, since hands-on support at this stage is exactly what separates a program you can actually follow from one you're left to figure out alone.

If needles make you anxious

This is common and worth naming rather than pushing through silently. Smaller, thinner pen needles than people expect, a numbing option (an ice cube on the site for a few seconds before cleaning it), and simply not watching the needle go in all help. If anxiety is a real barrier, tell your prescriber — some providers can walk you through your first injection on a video visit, which is one more reason clinician support is worth weighing when you choose a GLP-1 provider, not just price.

The mechanics are genuinely simple once you've gone through the motion a few times: pick one of three approved sites, rotate every dose, and follow your specific pen's instructions for use. What matters more for your results is consistency week to week — not which of the three sites you happen to use.