Definition: A subcutaneous injection (SubQ) puts medicine into the layer of fat just under the skin, above the muscle. GLP-1 pens like Wegovy and Mounjaro are labeled for subcutaneous use, and so is one testosterone product, Xyosted. Most peptides people track are also given this way.
The Wegovy label says to inject in the abdomen, thigh, or upper arm. The Mounjaro label lists the abdomen or thigh, or the back of the upper arm if another person gives the shot. Both labels say to rotate injection sites with each dose.
Xyosted, a testosterone enanthate autoinjector, is labeled for subcutaneous injection in the abdominal region only, and its label says to avoid intramuscular or intravascular injection. That is a useful reminder that the route belongs to the product: the same hormone can be labeled SubQ in one product and intramuscular in another.
The route changes how a drug is absorbed, so a dose given SubQ and the same dose given into muscle are not the same event. Log the route along with the site. If you switch routes, note the date so you can read later changes in how you feel against it.
Site matters too. Repeated SubQ shots into one patch of skin can cause lumps of thickened fat (lipohypertrophy) that absorb medicine unevenly. Dose Track lets you log the injection site with each dose, which makes a rotation easy to see at a glance.
Read more on Dose Track: Why injection site rotation matters · Wegovy guide · Mounjaro guide