# Where to inject semaglutide and tirzepatide: sites and rotation

Canonical page: https://bodienvi.com/blog/semaglutide-tirzepatide-injection-sites

Published October 28, 2026. Updated October 28, 2026. By Bodi Envi Clinical Content Team.

Where the Wegovy® and Zepbound® labels say to inject, how to rotate sites each week, what injection site reactions look like, and what changes with a vial.

## The three areas the labels name

Both medications are injected subcutaneously, into the fatty layer just under the skin, never into a muscle or a vein. The labels name the same three areas.

| Area | Wegovy® (semaglutide) | Zepbound® (tirzepatide) |
| --- | --- | --- |
| Stomach (abdomen) | Yes, the lower stomach, at least 2 inches from the belly button | Yes, at least 2 inches from the belly button |
| Thigh | Yes, the front of the thigh | Yes |
| Upper arm | Yes | The back of the upper arm, injected by another person |

The one real difference is the arm. The Zepbound® instructions say the back of the upper arm should be injected by someone else. Both labels report that the medication reaches similar levels in the blood whichever of the three areas is used, so the choice comes down to comfort and what you can reach.

This pertains to the brand name only. You cannot compare the personalized compounded version to this study because it is a different product entirely. For personalized compounds, the medical provider should be consulted.

## Rotating sites every week

Both labels say to rotate the injection site with each dose. Rotating does not mean changing body area every week. The Zepbound® medication guide says you may use the same area, as long as you choose a different spot within it each time. The Wegovy® label adds that the injection site and the time of day can change without any change to the dose.

The Zepbound® instructions also say not to inject where the skin is tender, bruised, scaly or hard, or into scars or damaged skin. A simple habit helps: keep a note of where the last dose went, and move a few inches over, or to the other side, for the next one.

This pertains to the brand name only. You cannot compare the personalized compounded version to this study because it is a different product entirely. For personalized compounds, the medical provider should be consulted.

## What injection site reactions look like

Redness, itching, bruising, mild pain or a small firm area where the needle went in are the reactions the labels describe. How often they were reported in the trials:

| Trial group | Medication | Placebo |
| --- | --- | --- |
| Wegovy®, adults in the weight trials | 1.4% | 1% |
| Zepbound® 5 mg to 15 mg | 6% to 8% | 2% |

Most settle on their own. Tell your care team about a reaction that keeps coming back or does not settle. The labels list the signs of a serious allergic reaction, which need medical help right away: swelling of the face, lips, tongue or throat, problems breathing or swallowing, severe rash or itching, fainting or feeling dizzy, and a very rapid heartbeat.

## Pens, vials and syringes

Branded pens hide the needle and fix the dose. A vial is drawn up with a syringe, and the labels are firm about one rule: use a new syringe and needle for every injection, and never share them, because shared needles can spread serious infections. The Zepbound® vial instructions describe a 1 mL syringe chosen with your healthcare provider.

Personalized compounded medications come in a vial, and for a vial the pharmacy’s instructions on drawing up the dose apply, not the instructions written for a branded pen. Your care team can answer questions before your first injection.

## If you also inject insulin

The Mounjaro® label, which covers tirzepatide for type 2 diabetes, says that when it is used with insulin the two should be given as separate injections and never mixed. They can go in the same body area, but not right next to each other.

This pertains to the brand name only. You cannot compare the personalized compounded version to this study because it is a different product entirely. For personalized compounds, the medical provider should be consulted.

## What this means for a compounded prescription

The sites, rotation and reaction rates above come from the Wegovy®, Zepbound® and Mounjaro® labels, which describe the FDA-approved products. Personalized compounded semaglutide and tirzepatide are not FDA-approved and were not studied in these trials.

Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations.

At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

## Frequently asked questions

### Which injection site works best?

Both labels report similar medication levels from the stomach, thigh and upper arm, so the best site is the one you can reach comfortably and rotate around. Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations. At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

### Can I inject in the same spot every week?

No. Both labels say to rotate with each dose. You can stay in the same area, as long as each injection goes in a different spot within it. Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations. At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

### Can I inject into my own arm?

The Wegovy® label lists the upper arm as a self-injection site. The Zepbound® instructions say the back of the upper arm should be injected by another person. Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations. At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

### I have a red, itchy bump where I injected. Is that normal?

Injection site reactions such as redness, itching and bruising were reported in the trials and usually settle on their own. Tell your care team if one keeps coming back, and get medical help right away for any sign of a serious allergic reaction. Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations. At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

### Can I change my injection site or time of day?

Yes. The Wegovy® label says both can change without a change to the dose. Personalized compounded medications differ from commercially available brand-name products in formulation, concentration, excipients, preparation methods, and other characteristics. Accordingly, clinical data from studies involving brand-name products should not be assumed to apply to personalized compounded formulations. At this time, the studies referenced above have not evaluated the specific personalized compounded formulations being provided. Therefore, no claims of equivalence in safety, efficacy, quality, or clinical outcomes should be inferred from these studies.

## Sources

- Wegovy® (semaglutide) injection prescribing information, DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b (checked October 2026)
- Zepbound® (tirzepatide) injection prescribing information, DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b (checked October 2026)
- Mounjaro® (tirzepatide) injection prescribing information, DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0 (checked October 2026)