Subcutaneous injection sites are the areas of the body where an injection goes into the tissue just under the skin, rather than into muscle. This page is a reference for where those areas are, as public health sources describe them, and for the part of the job that is easy to lose track of: moving between them.
It is not a technique guide. Needle angle, skin pinching and preparation are shown in person by a healthcare professional or pharmacist, and the product labelling can override anything general written here.
Where are the subcutaneous injection sites?
MedlinePlus lists three areas: the upper arms, the outer side of the upper thighs, and the belly. Memorial Sloan Kettering adds the upper area of the buttocks as a fourth.
Commonly listed subcutaneous injection sites
| Area | Where it sits, per the references | Listed by |
|---|---|---|
| Belly | Below the ribs and above the hip bones, at least 5 cm from the belly button | MedlinePlus, Memorial Sloan Kettering, Royal Children's Hospital |
| Thigh | The front or outer side of the upper thigh, roughly halfway between the knee and the hip | MedlinePlus, Memorial Sloan Kettering, Royal Children's Hospital |
| Upper arm | The side or back of the upper arm, at least 7.6 to 8 cm below the shoulder and above the elbow | MedlinePlus, Royal Children's Hospital |
| Upper buttock | The upper area of the buttock | Memorial Sloan Kettering |
The measurements come from MedlinePlus, which gives 3 inches (7.6 cm) for the arm and 2 inches (5.1 cm) for the belly button, and from the Royal Children's Hospital guideline, which gives 8 cm and more than 5 cm. The NDSS gives a smaller belly button margin, 1 cm, for insulin, a reminder that product guidance can differ. Lists that count five or more sites divide the same areas differently; the references used here name four.
Memorial Sloan Kettering notes that the back of the upper arm is for when someone else is giving the injection, rather than for injections given alone.
Which skin is avoided?
Skin that is not healthy. MedlinePlus says the site should show no redness, swelling, scarring, bruising, or other damage to the skin or the tissue below it.
healthdirect adds scars, stretch marks and lumps to the list, and Memorial Sloan Kettering adds skin that is tender or hard. The belly button margin covered above is the other common exclusion.
Why are injection sites rotated?
To give the skin and the tissue under it time between uses. MedlinePlus advises changing the site from one injection to the next, at least 1 inch apart, to keep the skin healthy and help the body absorb the medicine.
Memorial Sloan Kettering is more direct about the alternative: using the same spot each time makes scar tissue form.
What is lipohypertrophy?
A firm, fatty lump under the skin at a spot that has been used repeatedly. An NHS diabetes service notes that not rotating injection sites can cause lipohypertrophy, and that the lumps can mean insulin is not absorbed properly.
The NDSS advises leaving an area with a fatty lump alone until the lump is gone. Most of what is published on lipohypertrophy comes from insulin care. How it applies to another product is a question for the prescriber, but the habit it asks for, a new spot each time, is the same.
A lump, a change in the skin, or anything unexpected at a site is worth raising with a healthcare professional rather than working around.
How do you keep track of injection site rotation?
Record the site with the dose. A rotation only works if the last site is known, and after a week of doses that is the detail memory drops first, which is why Memorial Sloan Kettering suggests a notebook or calendar to keep track.
Diabetes education tends to turn rotation into a pattern rather than a choice made fresh each time. The NDSS describes imagining a flower on the belly, one petal for each day of the week and a slightly different spot within the petal each time. An NHS service puts the same idea as moving around within an area as well as using a different area.
- Agree the areas and the pattern with your healthcare professional, then write them down.
- Log the site at the moment of the dose, alongside the time and the amount. What to track in a peptide log covers the rest of the record.
- Check the last entry before the next dose, rather than relying on memory.