Where GLP-1 pens are injected, per the label

The site rule in each label

Tablets such as Rybelsus®, Wegovy® tablets and Foundayo™ have no injection site, so they are not in the table. For the seven weekly or daily injections, the administration section is short and the wording is close. The table keeps each label’s own nuance and the section where you can read it in full.

The upper arm: who gives the injection

The back of the upper arm is hard to reach and hard to pinch with one hand, and several documents say so in their own way. The Mounjaro® and Zepbound® labels place it with another person ^[1][2]. The Ozempic® prefilled syringe instructions list it with the words “only with help from someone else”, and the Victoza® pen instructions allow the upper arm only if a caregiver gives the dose ^[3][6].

The other labels are less specific. The US Wegovy®, Saxenda® and Trulicity® labels name the upper arm without a condition ^[4][5][7], while the EU Trulicity® leaflet names the stomach and the thigh for self-injection and the upper arm when someone else injects ^[11]. In Canada, the professional section of the Zepbound® monograph lists the upper arm plainly, while its patient information says another person should inject there ^[15]. If you inject alone, the leaflet in your own pack is the one to follow.

Is one area better than another?

No label ranks the areas. Each clinical pharmacology section (12.3) looks at how much medicine reaches the blood from each site: similar exposure from the abdomen, thigh and upper arm for semaglutide and tirzepatide, exposures considered similar for liraglutide, and no statistically significant effect of the site for dulaglutide ^{[1][2][3][4][5][7]}. The Victoza® label gives the detail behind its conclusion: exposure from the thigh was 22% lower than from the abdomen, yet the three sites were still judged comparable ^[6].

The Wegovy®, Saxenda® and Victoza® labels, and the EU Ozempic® document, say the site can be changed without adjusting the dose ^[4][5][6][8]. In practice the choice comes down to comfort, reach, clothing and what you were shown at the start. What the labels do care about is that the same spot is not used again and again.

Choosing the exact spot within an area

The Instructions for Use and patient leaflets go further than the prescribing information. Their advice overlaps, but each adds something:

• Distance from the navel: the Ozempic® prefilled syringe and Wegovy® pen instructions keep injections in the stomach area at least 2 inches (5 cm) from the belly button ^[3][4].
• Which part of the leg: the Wegovy® pen instructions point to the front of the thighs and the lower stomach ^[4].
• Skin to skip: tender, bruised, red or hard skin, scars and stretch marks in the Wegovy® instructions ^[4]; in the Canadian Mounjaro® and Zepbound® patient information also scaly or damaged skin, skin with pits, thickening or lumps, and a spot used for another medicine ^[14][15].
• Same area, new spot: the Wegovy® instructions allow the same body area each week as long as the spot changes, and the Ozempic® syringe instructions ask you to avoid the exact spot used last time ^[3][4].
• Cleaning: the Wegovy® instructions allow an alcohol swab or soap and water, then the skin should dry before the injection ^[4].
• General guidance: MedlinePlus, for subcutaneous injections of any medicine, asks for healthy skin without redness, swelling or scarring and spaces each injection at least 1 inch (about 2.5 cm) from the previous one ^[13].

Why the labels keep asking for rotation

What the labels support: the US Saxenda® and Victoza® labels link rotation within a region to a lower risk of cutaneous amyloidosis, a skin change listed among their postmarketing reports (section 6.2) ^[5][6]. The EU Saxenda® document words it as injection site amyloid deposits ^[12]. The Canadian Mounjaro® vial instructions name two conditions that changing the spot helps to avoid, lipodystrophy (pits or thickened skin) and localised cutaneous amyloidosis (lumps), and the Canadian Zepbound® patient information speaks of thinning, thickening or lumps ^[14][15].

What is general knowledge: MedlinePlus explains that moving the site keeps the skin healthy and helps the body absorb the medicine well ^[13]. Whether a particular lump came from one spot is for a clinician to judge, which is one reason a site record helps.

Two injections on the same day

The Ozempic®, Mounjaro®, Victoza® and Trulicity® labels cover insulin in the same way: two separate injections, never mixed in one syringe, and if they go in the same body region they should not be next to each other ^[1][3][6][7]. The EU Mounjaro® document is stricter in wording and asks for a different injection site when insulin is also injected ^[10], and the Canadian patient information says not to use a spot that was used for other medicines ^[14][15].

In Europe, the Wegovy® 7.2 mg dose can be given as one injection or as three 2.4 mg injections depending on the device; the leaflet allows the same body area for all three, at least 5 cm apart ^[9]. If your prescription involves more than one injection, ask your pharmacist how the spots should be spaced.

How often the skin reacted in trials

Section 6.1 of each label counts injection site reactions against placebo, and the numbers vary by product and trial pool: 0.2% with Ozempic® ^[3]; 1.4% with Wegovy® versus 1% with placebo ^[4]; 3.2% with Mounjaro® versus 0.4% ^[1]; 6% to 8% across Zepbound® doses versus 2% ^[2]; 13.9% with Saxenda® versus 10.5% ^[5]; and about 2% with Victoza® ^[6]. Those figures come from different trials and are not a comparison of the products. Redness, itching, bruising and discomfort are the usual examples, and our article on injection site reactions covers them in detail.

Ozempic®, Wegovy®, Rybelsus®, Saxenda® and Victoza® are registered trademarks of Novo Nordisk A/S. Mounjaro®, Zepbound® and Trulicity® are registered trademarks and Foundayo™ is a trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company.

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