How to Inject GLP-1 Medications: Sites, Rotation and Timing

Weekly self-injection is the single biggest reason people hesitate to start a GLP-1 drug, and most of that hesitation is about not knowing the mechanics. The FDA-approved prescribing information for Wegovy and Zepbound is specific about where, how and when — this is that information, not general injection advice.

Where to inject

Both drugs are approved for subcutaneous (under-the-skin, not muscle) injection in the same three areas: the abdomen, the front of the thigh, or the back of the upper arm. If injecting the abdomen, stay at least 2 inches from the navel. The back of the upper arm is difficult to self-inject accurately and is generally the site a caregiver or partner administers rather than the patient. The FDA labeling for both drugs states there is no clinically meaningful difference in absorption between the three approved sites when proper technique is used — so site choice is about comfort and access, not efficacy.

Rotating sites correctly

The instructions call for rotating the injection site each week — not necessarily to a different body area, but to a different exact spot within it. Using the abdomen every week is fine as long as you are not injecting the same square inch repeatedly. Skin that is tender, bruised, scarred, damaged, pitted, thickened or lumpy should be avoided regardless of which area it's in — those are signs of tissue that hasn't recovered from a previous injection or isn't suited for one.

Timing: same day, once a week

Both drugs are dosed once weekly, on the same day each week, with or without food, at any time of day. If you need to change your chosen day, both labels allow it as long as the minimum spacing rule for that drug is respected — see the missed-dose rules below, which are really the same spacing rule read from the other direction.

If a dose is late

- **Wegovy:** at least 48 hours must separate any two injections. Take a late dose as soon as you remember if your next scheduled one is more than 48 hours away; otherwise skip it and resume your normal day. - **Zepbound:** you have up to 4 days (96 hours) to take a late dose. Beyond that, skip it. Never take two Zepbound doses within 3 days (72 hours) of each other.

The full escalation schedule both drugs follow before reaching these weekly maintenance doses is in GLP-1 dosage and titration schedules.

Storage and pen handling

Both pens are shipped and stored refrigerated, and both labels allow a defined period at room temperature once removed from the fridge — check the specific number of days on the pen's own package insert, since it has changed across label revisions and differs slightly by product. Never inject through clothing, and inspect the medication through the pen's viewing window before injecting; both labels direct patients not to use a pen if the liquid looks cloudy, discolored, or contains particles.

When this becomes a provider question, not a technique one

Persistent injection-site pain, spreading redness, or a lump that doesn't resolve after a couple of weeks is a reason to contact your provider rather than switch injection sites and hope. For the drug's broader side-effect picture beyond the injection site itself, see GLP-1 side effects. And if the needle itself — not the schedule or the technique — is the real barrier, injections vs oral GLP-1 covers what changes and what evidence you give up by switching to a needle-free route.