Tirzepatide is injected under the skin in one of three places: the abdomen, the front of the thigh, or the back of the upper arm. The label says to rotate sites and does not rank one as best. You can inject at any time of day, with or without food, once a week. Pens and vials use the same three sites. If you are new to the drug, start with our tirzepatide guide, then follow the steps below.
Key takeaways
- Labeled sites: abdomen, thigh, upper arm. Subcutaneous only, never into muscle or a vein.
- Rotate. The label says to use a different site each week, and if you reuse an area, not the same spot.
- No trial in the Sources compared weight loss by injection site, so there is no "best place for weight loss." Pick the site you can reach and rotate.
- Injection site reactions are a listed common adverse reaction on the Zepbound label; most are mild.
- Storage matters as much as site: 2 to 8 C in the fridge, up to 21 days unrefrigerated for brand product, pharmacy label for compounded vials.
Tirzepatide injection sites: the three labeled options
| Site | Where exactly | Practical notes |
|---|---|---|
| Abdomen (stomach) | The soft area of the belly, away from the navel, scars and the waistband line | Easiest to see and reach; plenty of area to rotate across |
| Thigh | The front or outer part of the upper leg, between the knee and the hip crease | Easy to reach seated; alternate legs week to week |
| Upper arm | The fleshy back of the arm between the shoulder and the elbow | Hard to reach on yourself; many people need someone else to give this one |
Source: Zepbound and Mounjaro prescribing information, Dosage and Administration (subcutaneous injection in the abdomen, thigh or upper arm; rotate sites).
Avoid skin that is bruised, tender, red, hard, scarred or currently reacting from a previous shot. If your usual site is unavailable, any of the other two is fine. The label does not describe injecting anywhere else, so do not.
Best place to inject tirzepatide
There is no best place on the label, and the trials did not test sites against each other. What matters is that the injection is subcutaneous, into the fatty layer just under the skin, and that you rotate. People often find the abdomen easiest for a self-injection and the thigh easiest when sitting. The upper arm usually needs a helper. Choose by reach and comfort, and change it each week. Searches for the "best place to inject tirzepatide for weight loss" have an honest answer: the one you can rotate through reliably.
Check your GLP-1 eligibility
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Try the BMI Calculator →Rotation: how to move between sites
The label says to rotate. It does not prescribe a pattern, so here is a simple one that covers a month.
| Week | Site | Side |
|---|---|---|
| 1 | Abdomen | Left of the navel |
| 2 | Thigh | Right leg |
| 3 | Abdomen | Right of the navel |
| 4 | Thigh | Left leg |
Source: an example pattern applied to the label's instruction to rotate sites. Any rotation across the three labeled sites is acceptable.
If you only use the abdomen, move around it: left, right, higher, lower. Write the site on your calendar with the date so you do not repeat a spot.
How to inject tirzepatide at home, step by step
Brand Zepbound and Mounjaro pens have a hidden needle and a fixed dose. Zepbound also comes in single-dose vials. Compounded tirzepatide usually comes in a multi-dose vial you draw with a U-100 insulin syringe. The site and the skin prep are the same for all three.
| Step | Pen | Vial and syringe |
|---|---|---|
| 1. Prepare | Wash hands. Check the label for the right strength and the expiration date. Look at the liquid; it should be clear and free of particles. | Wash hands. Check the concentration (mg/mL) and beyond-use date. Look at the liquid for clarity. |
| 2. Choose and clean the site | Pick abdomen, thigh or upper arm. Wipe with alcohol and let it dry. | Same. |
| 3. Get the dose | Uncap the pen. The dose is fixed. | Wipe the vial top. Draw air equal to your units, inject it into the vial, turn the vial upside down, draw your units, tap out large bubbles. |
| 4. Inject | Place the pen flat on the skin, unlock, press and hold until the pen signals it is done. | Pinch a fold of skin if your pharmacy advises, insert the needle straight in, push the plunger fully, wait a few seconds, withdraw. |
| 5. Finish | Drop the used pen in a sharps container. | Drop the syringe in a sharps container without recapping. Return the vial to the fridge. |
Source: general subcutaneous technique consistent with the Zepbound and Mounjaro prescribing information; follow the Instructions for Use in your box or your pharmacy's directions where they differ.
The Zepbound pen video shows the pen steps on camera. For the vial route, including the unit math, go to how to inject with a syringe.
Needle and syringe basics
You do not choose a needle for a brand pen; it is built in. For a compounded vial, the pharmacy supplies syringes, usually U-100 insulin syringes where 1 mL equals 100 units. Your dose in units depends on the vial's concentration: at 10 mg/mL, 2.5 mg is 25 units and 5 mg is 50 units. Insulin syringes are designed for subcutaneous injection, which is why they are used here. Gauge and length options are covered on tirzepatide needle size; we do not list numbers here because the pharmacy's supplied syringe is the one to use.
Storage before and after injecting
| Rule | Brand pens and vials (label) | Compounded vials |
|---|---|---|
| Refrigerate | 2 to 8 C (36 to 46 F) | Per pharmacy label, usually refrigerated |
| Out of the fridge | Up to 21 days at up to 30 C (86 F) | Per pharmacy label; may be shorter |
| Freezing | Do not freeze; discard if frozen | Do not freeze |
| Light | Protect from light | Protect from light |
Source: Zepbound and Mounjaro prescribing information, How Supplied/Storage and Handling; compounded storage from the dispensing pharmacy.
See what happens if tirzepatide gets warm if a shipment or a trip went wrong.
Injection site reactions
The Zepbound label lists injection site reactions among the most common adverse reactions, meaning they occurred in at least 5% of participants and more often than with placebo. Redness, itching or a small bump at the site that fades over a day or two is the usual picture. A spreading rash, hives, swelling of the face or throat, or trouble breathing is a different problem: the label warns about serious hypersensitivity reactions, and those need care right away. Details are on tirzepatide injection site reactions.
What this means for compounded tirzepatide
The sites, the rotation and the storage principles are the same; the delivery is a syringe instead of a pen. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro; a licensed provider decides whether it is appropriate. At FormBlends, injection supplies are included with every shipment, medication ships cold-chain from state-licensed 503A compounding pharmacies, and compounded tirzepatide is $149 for the first month, then $239 a month, or $214 a month with Subscribe & Save, at any dose. See pricing or begin at start.
Frequently Asked Questions
Where do you inject tirzepatide?
Under the skin of the abdomen, the front of the thigh, or the back of the upper arm. Rotate sites each week. Those are the only three sites on the label.
What is the best place to inject tirzepatide?
The label does not rank the sites and no trial compared them for weight loss. The abdomen is easiest for most self-injections, the thigh is easy seated, and the upper arm usually needs a helper.
Where do you inject tirzepatide in the thigh?
The front or outer part of the upper leg, between the knee and the hip crease, away from the inner thigh. Alternate legs from week to week.
How do you inject tirzepatide in the stomach?
Choose a soft area away from the navel, scars and the waistband, clean it with alcohol, and inject straight into the fatty layer under the skin. Move to a different part of the abdomen next time.
Can you inject Zepbound in the arm?
Yes. The back of the upper arm is a labeled site. Because it is hard to reach on yourself, most people have someone else give arm injections.
How do I inject tirzepatide at home for the first time?
Wash your hands, check the label, clean the site, then use the pen or draw your units from the vial and inject under the skin. Dispose of the needle in a sharps container. Your prescriber or pharmacy can walk you through the first one.
Sources
- Zepbound (tirzepatide) prescribing information, Eli Lilly via DailyMed, revised 08/2026.
- Mounjaro (tirzepatide) prescribing information, Eli Lilly via DailyMed, revised 08/2026.
- Zepbound US prescribing information (PDF), Eli Lilly, 2026.
- Mounjaro US prescribing information (PDF), Eli Lilly, 2026.
- FormBlends pricing, Form Blends LLC, verified September 5, 2026.
Next steps
Read how to inject with a syringe for the vial route and injection site reactions for what is normal afterward. Browse the tirzepatide hub for every other tirzepatide question. Talk to a clinician or pharmacist if you are unsure about any step. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro; a licensed provider decides whether it is appropriate for you.
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