Short answer: GLP-1 weight-loss injections are given into subcutaneous tissue, just under the skin. There are three main approved injection areas: the abdomen, at least 5 cm (about 2 inches) away from the belly button; the front-middle of the thigh; and the outer back part of the upper arm.

Key takeaways

  • 3 main areas: the abdomen (right/left), thigh (right/left) and upper arm (right/left), giving 6 rotation points.
  • Injecting into the same spot repeatedly leads to tissue hardening (lipohypertrophy) and disrupts absorption of the medication.
  • The Haftra app remembers the previous site every week and visually shows the next rotation point.
  • Never inject into a muscle or a vein; the medication goes only into the fat tissue under the skin.

GLP-1 injections are given under the skin (subcutaneously). The areas listed in the product information are the abdomen, the front of the thigh and the outer upper arm. Choosing a different spot for each injection is recommended: this is called site rotation.

This page is for general information only and does not replace medical advice. Injection site, dose and duration are decisions for your doctor alone. The package leaflet for your own medication takes priority over the general information on this page.

Which areas are used?

  • Abdomen: as long as you stay about five centimeters (about 2 inches) away from the belly button.
  • Front of the thigh: the middle area, away from the knee and groin.
  • Outer upper arm: usually easier when someone else gives the injection.

The product information does not state that any of the three areas is more effective than the others. The choice is mostly about which area you can reach comfortably.

Why is rotation needed?

Injecting into the same spot again and again can cause hardening and tissue changes under the skin. Absorption of the medication can vary in changed tissue, which means the same dose may behave differently from week to week. Rotation is there to prevent this.

Injection site reactions such as redness, bruising and tenderness also become more noticeable when the same spot is used constantly.

How do you plan rotation?

A common method is to move through the three areas in turn and choose a different spot within each area as well. For example, moving from the upper right quarter of the abdomen to the upper left quarter the next week lets a few weeks pass before you return to the same area.

If you are not logging your injections somewhere, it gets hard after a few weeks to remember which spot you used and when. This is exactly where rotation breaks down in practice.

What to watch for

  • Do not inject into an area that is red, swollen, hard, tender or injured.
  • The area should be clean before the injection.
  • Use a new, sterile needle for every injection.
  • Mild redness at the injection site usually goes away on its own; see a doctor for lasting hardening or spreading swelling.

Tracking the site

Haftra shows how many days have passed since each of the six sites was last used and reminds you of the next site. It does not decide which site is healthiest; it makes it easier to follow the rotation instructions in the product information. It is free and can be used without an account.

iPhone, iPad and Apple Watch. Free.

Frequently asked questions

Where is a weight-loss injection given?

The areas listed in the product information are the abdomen, the front of the thigh and the outer upper arm. The injection goes under the skin. On the abdomen, you need to stay about five centimeters (about 2 inches) away from the belly button.

Why is it given in a different spot each time?

Injecting into the same spot again and again can cause hardening and tissue changes under the skin. Absorption of the medication can vary in changed tissue, which means the same dose may behave differently from week to week. Rotation keeps absorption consistent from dose to dose.

Can I use the same area two weeks in a row?

A common method is to move through the three areas in turn and choose a different spot within each area as well. The aim is for a few weeks to pass before you return to the same area.

Which area is more effective?

The product information does not state that any of the three areas is more effective than the others. The choice is mostly about which area you can reach comfortably.

Where does a weight-loss injection hurt the least?

For most users, the abdomen hurts the least because it usually has the most fat tissue.

Can you inject into your own arm?

An arm injection is usually easier with someone else's help; if you are injecting alone, the abdomen or thigh is preferable.

Sources

  • EMA - Mounjaro (tirzepatide)
  • EMA - Ozempic (semaglutide)
  • EMA - Wegovy (semaglutide)
  • NHS - Obesity treatment
  • U.S. Food and Drug Administration (FDA)

Last reviewed: August 4, 2026