Injection-Site Rotation: Protect Your Skin and Keep Better Records

If you use a prescribed subcutaneous medicine, repeatedly returning to one convenient spot can create problems. Rotation deserves the same attention as checking the product and recording the amount. In insulin care, fatty lumps under the skin are known as lipohypertrophy, and injecting into them can make absorption less predictable.¹

What the absorption evidence actually shows

A controlled crossover study in 13 people with type 1 diabetes compared insulin lispro injected into lipohypertrophic tissue with injections into normal tissue. Absorption and action were lower and more variable in the affected areas, with worse post-meal glucose control.²

A practical way to remember your sites

Use the sites and technique specified for your medicine and device. Insulin guidance commonly describes the abdomen, thighs and buttocks, but an insulin diagram is not permission to use any body region for a different product.^1,3

1. Name the region and side in your record, for example ‘left abdomen’, then identify the exact point within it. A broad region is not the same as one injection spot.
2. Choose a different point each time within the areas your healthcare team has shown you. Diabetes UK advises at least 1 cm between insulin injection points. Follow the spacing and navel clearance in your own medicine’s instructions.³
3. Record the date, time and site immediately, so your next choice is based on a history rather than memory.
4. Inspect and gently feel the area before use. Avoid an existing lump, inflamed area or damaged skin, and ask a clinician to assess changes that persist.³

A week off is not proof that a lump has healed

Do not use a fixed calendar rule to decide that abnormal tissue is ready again. A site that remains firm, raised or uncomfortable needs assessment. A new lump could have several causes; do not diagnose it from a photograph or assume every swelling is lipohypertrophy. Diabetes UK specifically notes that persistent injection-site lumps deserve professional advice.³

Use a fresh needle each time and dispose of it in an appropriate sharps container. If you use insulin and change away from a repeatedly used abnormal site, discuss monitoring and any dose adjustment with your diabetes team. Better absorption can change the effect of the same recorded amount.^1,2

Record more than a syringe number

A record such as ‘10 units’ cannot tell you the peptide amount unless you also know the concentration and syringe scale. U-100 markings represent 100 units per mL; U-40 markings represent 40 units per mL. The same number therefore represents different liquid volumes. Confusion between mg, mL and syringe units has caused medication errors.⁴

Both rows describe the same mass. Changing the diluent changes the volume needed; changing the syringe scale changes the marking. Use the PSA U-40/U-100 calculator with your actual vial values. It checks arithmetic and does not choose a treatment dose.

Track the full picture in your daily log

• Dose and time: compound, amount, mass unit, and any relevant concentration or syringe information.
• Site and local response: region, side, exact-point notes, pain, swelling and changes you notice.
• Daily observations: sleep hours, weight, energy, symptoms and side effects. Leave an unmeasured field blank rather than entering a guessed score.
• Bloodwork and other measures: keep the test date, exact units and lab reference range. Include training, illness or medication changes that may help explain the context.

Open Daily Log in the PSA tracker to save a check-in alongside your dose history and export the selected 30-day period. A personal record can support a useful clinical conversation; it cannot establish that a peptide caused a change.