Guides / Mixing and syringes
GLP-1 injection sites and how to rotate them
Stomach, thigh and upper arm all work equally well for semaglutide and tirzepatide. Changing the exact spot each week is what the labels ask for.
[00] Short answer
- Ozempic, Wegovy, Mounjaro and Zepbound are injected under the skin of the stomach, thigh or upper arm1–4. Mounjaro and Zepbound labels say another person should give the upper-arm injection3–4.
- In the stomach, stay at least 2 inches (5 cm) from the belly button2,4–5.
- The labels say exposure to the medicine is similar in all three sites1–4.
- Rotate: use a different spot each dose. Staying in the same body area is fine1–3.
- Injection site reactions in trials: 0.2% on Ozempic, 1.4% on Wegovy, 3.2% on Mounjaro and 6 to 8% on Zepbound1–4.
Where can you inject Ozempic, Wegovy, Mounjaro and Zepbound?
All four go under the skin (subcutaneously) of the abdomen, thigh or upper arm1–4. The labels differ on who should give the arm injection and on how they word rotation.
| Medicine | Sites | Upper arm | Rotation wording |
|---|---|---|---|
| Ozempic (semaglutide) | Abdomen, thigh, upper arm1 | Back of the arm, only with help, in the prefilled syringe instructions1 | A different site each week when using the same body region1 |
| Wegovy (semaglutide) | Abdomen, thigh, upper arm2 | Allowed. Some device instructions say with help from someone else2 | Rotate injection sites with each dose2 |
| Mounjaro (tirzepatide) | Abdomen, thigh, back of upper arm3 | Another person should inject3 | Rotate injection sites with each dose3 |
| Zepbound (tirzepatide) | Abdomen, thigh, back of upper arm4 | Another person should inject4 | Rotate injection sites with each dose4 |
UK note: the UK Mounjaro KwikPen leaflet lists the same three areas, says someone else should help with the back of the upper arm, and says to use a different site if you also inject insulin6.
Does the injection site change how well a GLP-1 works?
No, according to the labels. Similar exposure was seen with semaglutide and with tirzepatide injected in the abdomen, thigh or upper arm1–4. The Wegovy label adds that the injection site can be changed without changing the dose2.
So pick the area you can reach, see and rotate within. You can do your own stomach and thigh. For Mounjaro and Zepbound, the labels say the upper arm needs a second person3–4.
How do you rotate GLP-1 injection sites?
Use a new spot each dose. You can stay in the same body area, as long as it's not the exact spot you used last time1–3.
- Choose an areaStomach, thigh or upper arm. In the stomach, keep at least 2 inches (5 cm) from the belly button2,4–5.
Why do you get a bruise or a drop of blood after a GLP-1 injection?
A drop of blood or liquid on the skin after the injection is normal, the Zepbound instructions say. Press a cotton ball or gauze on the spot, and don't rub it4. The Ozempic instructions say the same1.
In the Zepbound trials, bruising, redness, itching, pain and rash at the site were all counted as injection site reactions4. How often reactions happened depends on the medicine:
| Medicine | On the medicine | On placebo |
|---|---|---|
| Ozempic | 0.2%1 | Not given |
| Wegovy (adults, weight trials) | 1.4%2 | 1%2 |
| Mounjaro (adults) | 3.2%3 | 0.4%3 |
| Zepbound (5, 10 and 15 mg) | 6%, 8% and 8%4 | 2%4 |
With Zepbound, reactions were more common in people who made antibodies to tirzepatide: 11.3%, against 1% in those who didn't4.
What are lumps at the injection site?
Repeated injections in one spot can cause skin changes. The Mounjaro and Zepbound vial instructions say to rotate within an area to lower the risk of lipodystrophy (pits or thickened skin) and localized cutaneous amyloidosis (lumps)3–4.
Most of what's known comes from insulin, which people inject daily. In a 2013 study of 430 insulin users, 64.4% had lipohypertrophy, fatty lumps under the skin. Among those who rotated correctly, only 5% had it. Reusing needles more than 5 times also raised the risk7.
For weekly GLP-1 injections, we found no study measuring how often these lumps happen. There are single case reports. One describes a 75-year-old man on semaglutide who got firm, red, itchy, quarter-sized nodules after his dose went up to 1 mg. They lasted 2 to 4 days, kept appearing even after he rotated sites, and stopped when he switched to another GLP-18.
- Avoid lumpy, firm or numb spots until they settle. MedlinePlus calls these a common reason insulin doesn't work the way it should5.
- For pen needles, see needle sizes.
When should you call about an injection site reaction?
If a reaction keeps coming back or doesn't settle, tell your prescriber or pharmacist. In the case report above, the nodules stopped after a switch to a different GLP-18.
Other side effects are covered in GLP-1 side effects.
Questions
What is the best place to inject Ozempic or Mounjaro?
The labels treat the stomach, thigh and upper arm the same, with similar exposure at each. Choose the one you can reach and rotate within. Mounjaro's label says someone else should do the arm.
How far from the belly button should I inject?
At least 2 inches (5 cm), according to the Wegovy and Zepbound instructions and MedlinePlus.
Can I inject in the same spot every week?
The labels say to rotate with each dose. You can use the same area, such as your stomach, but pick a different spot from the one you used last time.
Is it normal to bruise after a GLP-1 injection?
It can happen. Injection site reactions, which in the Zepbound trials included bruising, affected 0.2% to 8% of people depending on the medicine. The labels say not to inject into bruised skin.
Does injecting in the stomach work better than the thigh?
No. The Ozempic, Wegovy, Mounjaro and Zepbound labels all say exposure was similar in the abdomen, thigh and upper arm.
Can I inject my GLP-1 next to my insulin?
The Ozempic label allows the same body region but not next to each other. Mounjaro and Zepbound say not to use the same site you use for other medicines.
Sources
Checked against US prescribing information and Instructions for Use for Ozempic, Wegovy, Mounjaro and Zepbound (2026), the UK Mounjaro KwikPen leaflet, MedlinePlus, and PubMed studies on lipohypertrophy and injection-site nodules. How we check
- 1Ozempic (semaglutide) injection, US prescribing information and Instructions for Use. Novo Nordisk, revised 05/2026; sections 2.1, 6.1, 12.3
- 2Wegovy (semaglutide) injection and tablets, US prescribing information and Instructions for Use. Novo Nordisk, revised 06/2026; sections 2, 6.1, 12.3
- 3Mounjaro (tirzepatide) injection, US prescribing information and Instructions for Use (DailyMed). Eli Lilly, Aug 2026; sections 2, 6.1, 12.3
- 4Zepbound (tirzepatide) injection, US prescribing information, Medication Guide and Instructions for Use (DailyMed). Eli Lilly, Aug 2026; sections 2, 6.1 (Table 1), 12.3
- 5MedlinePlus (US National Library of Medicine), Giving an insulin injection. reviewed 21 Jul 2024
- 6Mounjaro KwikPen, UK patient information leaflet (emc). revised Aug 2026; section 3
- 7Blanco M et al. Prevalence and risk factors of lipohypertrophy in insulin-injecting patients with diabetes. Diabetes Metab 2013;39(5):445-53. PMID 23886784
- 8Hearn EB, Sherman JJ. Injection-site nodules associated with once-weekly subcutaneous administration of semaglutide. Diabetes Spectr 2021;34(1):73-75. PMID 33627997; case report
This guide explains what labels and published studies say. It isn't medical advice and doesn't replace your prescriber or pharmacist.
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Read next
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- U-100 vs U-40 vs U-500 syringes, and needle sizesThe number after the U tells you how much liquid each unit line holds, so a syringe from the wrong scale gives the wrong dose even when you read it perfectly.