Wegovy, Ozempic, Zepbound and Mounjaro all permit the same three places: the belly, the thigh at the front, and the upper arm from behind. All four also give the same instruction — move the site every time.
The reason is worth understanding, because it is the difference between following a rule and knowing why you would not break it. Inject into the same patch repeatedly and the fat beneath it thickens into rubbery tissue. Drug delivered there is absorbed unpredictably — sometimes slower than normal, sometimes faster. Appetite suppression turns erratic, progress stalls, and the dose gets blamed for what the technique caused.
The three sites
| Site | Where exactly | Worth knowing |
|---|---|---|
| Abdomen | Anywhere across the front of the belly, keeping two inches clear of the navel in every direction. Stay off the waistband line. | The one most people use. Easy to reach one-handed, absorbs consistently. Avoid old surgical scars. |
| Front of thigh | The middle third, between knee and hip crease, toward the outer front rather than the inner thigh. | A good alternative when the abdomen is tender. Sit down and let the leg go slack. Some people find it absorbs a little slower. |
| Back of upper arm | The soft area over the triceps, midway between shoulder and elbow. | Realistically needs another person — pinching your own arm one-handed does not work well. If you live alone, plan around it rather than fighting it. |
An eight-week rotation
Two goals: never reuse the same spot inside four weeks, and keep two inches between consecutive injections even within one region. Abdomen is an area, not a target.
| Week | Site | Spot |
|---|---|---|
| 1 | Abdomen | Upper right, two to three inches out from the navel |
| 2 | Thigh | Right leg, mid-thigh |
| 3 | Upper arm | Right triceps |
| 4 | Abdomen | Upper left |
| 5 | Thigh | Left leg, mid-thigh |
| 6 | Upper arm | Left triceps |
| 7 | Abdomen | Lower right |
| 8 | Abdomen | Lower left |
Then start again. If the arms are out because nobody is around to help, use both thighs each cycle and spread across more of the abdomen — just keep the two-inch gap. What you must not do is quietly collapse the whole rotation onto one comfortable patch of belly.
Why the same spot is a genuine problem
- The lump absorbs unreliably. This is the main event. Thickened fat delivers the drug at a rate nobody can predict, so your dose stops meaning what it says.
- Site reactions compound. Red, itchy, raised skin is a listed reaction on all four labels. Rotating gives each spot time to recover.
- Bruises and hard nodules accumulate. Puncturing one square inch repeatedly breaks capillaries faster than they mend.
- At the extreme, skin breaks down. Reported in long-term insulin users with severe thickening who kept going into the same place — a plausible endpoint for any chronic injection.
- The trials rotated. Everyone in STEP, SURMOUNT, SUSTAIN and SURPASS followed a rotation protocol. Reusing one spot is not the technique the results came from.
Technique
- Let the pen warm up for fifteen to thirty minutes. Cold fluid stings considerably more going in. Never microwave it or hold it under hot water.
- Pinch a fold of skin and go straight in at ninety degrees. The pinch lifts the fat clear of the muscle underneath.
- Count to ten before withdrawing. Pull out early and some of it stays behind in the needle and on your skin.
- Do not rub afterwards. It speeds absorption unevenly and bruises you. Light pressure with cotton wool is fine.
- New needle every time on multi-dose pens. A blunt tip tears rather than pierces.
- Write it down — date, site, quadrant, on the box or in your phone. People who do not log it drift back to favorites without noticing, which is exactly how the lump forms.
Mistakes that are easy to make
- Injecting through clothing. Even thin fabric carries bacteria into the puncture and can knock the needle off angle. Bare, clean skin.
- Choosing stretch marks, tattoos, moles or scars. The blood supply there is not normal and neither is the absorption.
- Reusing needles to economise. It hurts more, damages tissue, and concentrates that damage wherever you already favor.
- Injecting straight from the fridge. Stings sharply, achieves nothing.
- Dropping the arm site and over-using the belly. Understandable, and the reason most rotations quietly fail. Substitute properly rather than just skipping.
Where to go next
- All cheat sheets — the full reference library.
- Where to inject, in more depth — the anatomy and the absorption evidence behind these three sites.
- Wegovy dose ladder — the titration this rotation runs alongside.
- Sick-day guide — when to hold a dose entirely.