Subcutaneous injection sites and how to rotate them

The usual subcutaneous (subQ) injection sites are the belly (at least 2 inches, or 5 cm, from the belly button), the outer upper thighs and the back or side of the upper arms; some guidance also includes the buttocks. Rotate so that each injection is at least 1 inch (2.5 cm) from the last, because injecting the same spot again and again can cause lumpy fatty tissue, called lipohypertrophy, that absorbs medicine unevenly. Before you inject, the syringe reader shows where your draw sits on a 30, 50 or 100-unit syringe.

The sites

Sources: MedlinePlus for the belly, thighs and upper arms; Embecta’s injection technique guide for the buttocks. The Zepbound and Ozempic labels list the abdomen, thigh and upper arm, and Zepbound’s label notes that the back of the upper arm should be injected by another person (Zepbound, Ozempic).

Skip any spot that is red, swollen, scarred, bruised or lumpy. The Egrifta WR instructions also rule out the belly button and “any hard bumps from previous injections” (Egrifta WR).

How to rotate

Embecta’s guide suggests dividing a site into four sections (or two halves for a thigh or buttock), using one section for a week and moving at least one finger’s width from the last injection each time. Ozempic’s label says to use a different injection site each week when injecting in the same body region.

A simple plan for a weekly injection:

1. Picture your belly as four squares around the belly button: upper left, upper right, lower left, lower right.
2. Use a different square each week, so each square gets one injection every 4 weeks.
3. Within a square, move at least a finger’s width (about 1 in) from where you went last time.
4. Write down where you injected, in a notebook or an injection log.

For daily injections, you’ll cover more ground, so use more than one body area and keep each new spot at least an inch from the last.

Why rotation matters: lipohypertrophy

Lipohypertrophy is a build-up of fatty tissue under skin that’s injected repeatedly. You may not see it, but you can often feel it as a soft or firm lump. The best evidence comes from insulin:

• In a study of 430 people injecting insulin, 64% had lipohypertrophy. It was strongly linked to not rotating sites, and the risk rose when needles were reused more than 5 times. Of those who rotated correctly, only 5% had it (Blanco et al., 2013).
• Insulin injected into these lumps was absorbed less, and far less predictably, than insulin injected into normal tissue (Famulla et al., 2016).
• International injection recommendations say not to inject into these lesions, and that correct site rotation helps prevent them (Frid et al., 2016).

These studies are about insulin. Whether other injected peptides behave the same way hasn’t been studied as well, but rotating and using a new needle each time are simple habits that protect your skin either way.

Giving the injection

1. Clean your hands and the site

   Wash your hands with soap and running water. Wipe the skin with an alcohol pad, moving outward from the spot, and let it dry.

2. Pinch up the skin

   Gently pinch about an inch of skin and fat, not muscle, between your fingers.

3. Insert the needle

   Insert it quickly, all the way in, at 90 degrees. Use 45 degrees if there’s very little fat at that spot.

4. Inject and withdraw

   Release the pinch, push the plunger all the way, then pull the needle straight out. Press with clean gauze if there’s a little blood.

5. Dispose of it

   Put the syringe straight into a sharps container. Never reuse or share needles.

These steps follow MedlinePlus. Follow your product’s own instructions where they differ.

The volume going in

Unit numbers tell you how much liquid you’re injecting under the skin. On a U-100 syringe, 20 units = 0.2 mL and 80 units = 0.8 mL. If a 10 mg vial is mixed with 2 mL (5 mg/mL), a prescribed amount of 1 mg is 0.2 mL, or 20 units. The same 1 mg from a vial mixed with 4 mL is 0.4 mL, or 40 units: twice the liquid. (Numbers for illustration only, not a dose.) The reconstitution calculator shows the volume for any vial. If your draws feel large, ask your pharmacist whether a different mix is appropriate.

Common mistakes

• Always using the same “easy” spot.
• Injecting into a lump, scar or bruise.
• Injecting too close to the belly button. Stay at least 2 inches away.
• Reusing needles. Reuse is linked to lipohypertrophy as well as infection.
• Not letting the alcohol dry, which can sting.

Questions people ask