Guide
Almost everyone rotates for the first month and then quietly settles on the two spots that hurt least. That drift is the whole problem, and it is invisible without a record — which is why a site log is worth more than good intentions.
Injecting the same small area repeatedly is associated with local changes to the fatty tissue — lumps, hardening, or in the case of insulin the well-documented lipohypertrophy. Beyond the cosmetic issue, altered tissue can absorb differently, which makes dosing less predictable from one injection to the next. That is the practical argument: rotation is about consistency as much as comfort.
None of this is a reason for anxiety about a single repeat. It is a reason to keep a record so that six months of accidental repetition does not happen without you noticing.
Complicated schemes get abandoned. What survives is something like: pick a region for the week — left abdomen, right abdomen, left thigh, right thigh — and move a couple of centimetres within it for each injection, then change region next week. The point is not the specific pattern; it is that the pattern is decided in advance rather than in the moment.
Keep at least a couple of centimetres between consecutive injections, and avoid anywhere currently bruised, tender or hardened.
A site log kept apart from the dose log will not be kept. Recording the site as part of logging the dose — one extra tap — is the only version that survives past a few weeks.
BioHack Track records the site with each dose and shows you which ones you have been leaning on, so “I have used my right abdomen eleven of the last fifteen times” is a thing you can see rather than suspect. It is free, with no limit on history.
Persistent hardness or a lump under the skin, an area that has become numb, redness or swelling that does not settle in a day, or the same site consistently stinging more than others. Any of those is worth a note against the site and, if it persists, a mention to your prescriber. Give an affected area a long rest rather than a short one.
Intramuscular injection — common for TRT — has its own site set and its own constraints, and rotation there is usually between a smaller number of larger sites. The principle is the same: decide the rotation in advance and record what you actually did. See the TRT tracking guide for the rest of that picture.
There is no single rule, and it varies by how often you inject and how much volume goes in. The practical version is to have enough sites in the rotation that you are not returning to one within a week, and to give any site that feels different a much longer rest.
Absorption can differ between regions — abdomen versus thigh, for instance — which is an argument for rotating within a region rather than jumping between them at random.
No. Injection-site rotation and the site history are free, with no history limit.
Yes. The default set covers the common subcutaneous and intramuscular sites, and you can log against whichever ones you actually use.
For personal tracking. Not medical advice, and not a substitute for your prescriber.