Injection Site Tracker Apps for Weekly GLP‑1 Shots

A good injection site tracker logs where each weekly GLP‑1 shot went, suggests the next spot and warns you before you reuse one. A paper log keeps the record; an app does the other two from your history, across 52 shots a year. Ozempic, Wegovy, Mounjaro and Zepbound all ask for a new spot each week (Ozempic and Zepbound labels).

Key facts

• Ozempic lets you stay in one body region week after week, as long as the exact injection site moves (Ozempic label, section 2.1).
• Mounjaro and Zepbound reserve the back of the upper arm for someone else, so self-injectors rotate between the abdomen and both thighs (Mounjaro label, section 2.2).
• Among 13,289 insulin users surveyed in 42 countries, health professionals found lipohypertrophy in 30.8%; the survey covered insulin, not weekly GLP‑1 shots (Frid et al., 2016).

What a site tracker has to do

A tracker has to record where each shot went, suggest the next spot, warn you before you reuse one and hold a note of any reaction at that site. A paper log or a phone note covers the record and the reaction note if you fill it in every week. An app is quicker at the other two because it reads back months of shots before it suggests a site or flags a repeat.

Checked in September 2026, the free tier of Pensday does three of these jobs, and a paper log does the one it misses.

Other apps, and what their free tiers leave out, are compared on price and features. A note of the date and site of each bruise or lump shows which spot to rest, while a lump that keeps coming back or skin that turns hot needs more than rest.

Why the labels ask you to rotate

Ozempic’s label asks you to "use a different injection site each week when injecting in the same body region" (Ozempic prescribing information, section 2.1). Wegovy, Mounjaro and Zepbound put it as "Rotate injection sites with each dose" (Wegovy, section 2.1; Mounjaro, section 2.2; Zepbound, section 2.4).

Your choice of site is not about the dose, since the abdomen, thigh and upper arm give similar exposure (Ozempic prescribing information, section 12.3). Rotating is for the skin. The Zepbound vial instructions link it to a lower risk of pitted, thickened or lumpy skin at the injection sites (Zepbound Instructions for Use).

If you take Mounjaro or Zepbound and inject yourself, rotate between your abdomen and both thighs. Both labels leave the back of the upper arm to another person (Mounjaro prescribing information, section 2.2; UK Summary of Product Characteristics, section 4.2), so pass over any arm an app suggests.

In the Injection Technique Questionnaire, health professionals examined 13,289 insulin users in 42 countries and found lipohypertrophy in 30.8% (Frid et al., Mayo Clinic Proceedings, 2016). People with the lumps used a mean of 10.1 more units of insulin a day, and the lumps went with incorrect rotation, small injection zones and reused pen needles. FITTER, the insulin recommendations informed by that survey, says lipohypertrophy distorts absorption and that correct rotation helps prevent it (Frid et al., New Insulin Delivery Recommendations, 2016). Because the survey covered insulin injections, it shows what happens when rotation fails; it does not estimate the risk for a weekly GLP‑1.

Rotation patterns

In insulin guidance, one scheme with proven effectiveness splits an area into quadrants, uses one each week and moves in the same direction, clockwise for example (FIT UK recommendations, section 3.6). With the Wegovy single-dose pen, a stomach shot goes in the lower stomach, at least 2 inches from your belly button (Wegovy Instructions for Use).

Tap your last few sites into the GLP‑1 injection site rotation chart and you get a zone for each of the next 8 weeks, spread over the belly and thighs.