Weight Loss Injection Beginning with S: What You Need to Know About Semaglutide

Semaglutide is a GLP-1 receptor agonist — it works by mimicking a hormone called glucagon-like peptide-1, which plays a role in regulating appetite and the feeling of fullness. When injected once a week, semaglutide acts on appetite-regulating pathways in the brain, and many people report reduced hunger and less preoccupation with food, sometimes described as quieter 'food noise'.

Wegovy (semaglutide) is supplied as a pre-filled, once-weekly injection pen. It is a prescription-only medicine, meaning it can only be used under the guidance of a prescriber or doctor. Dose levels are typically started low and adjusted over time — always according to your prescriber's direction, not a fixed universal schedule.

What about the weight loss injection beginning with 't'?

A closely related medicine is tirzepatide — the active substance in Mounjaro — which begins with 't'. Tirzepatide acts on both GLP-1 and GIP receptors (making it a dual agonist), and is also a once-weekly injectable prescription medicine for weight management. While both belong to the same broad family of GLP-1 treatments, they are different medicines, and which one is right for you is entirely a decision for your prescriber. You may also occasionally see references to a weight loss jab beginning with 'r' — this typically refers to older GLP-1 treatments such as liraglutide (brand name Saxenda), though semaglutide and tirzepatide are now the more widely prescribed options in this class.

Injection sites and rotation

Semaglutide is injected subcutaneously (just under the skin). The three commonly used sites are the abdomen, outer thigh, and upper arm. Rotating between sites with each injection is generally recommended to avoid skin irritation or changes at any single spot — your prescriber or the patient information leaflet that came with your pen can advise on the specifics of technique.

For a broader overview of how weekly weight loss injections work and what to expect, see our guide to weight loss injections, or read more about what a weight loss injection involves.

Rotating injection sites sounds straightforward — until you realise it is genuinely easy to forget where you injected last week. GLP Trackr's injection-site tracking feature lets you log each site as you go, so the app builds a rotation history and can suggest your next site automatically. No guessing, no repeating the same spot by accident.

Alongside site tracking, the app's dose logging means every injection — date, time, and dose strength — is recorded in one place. With a once-weekly schedule, a gentle dose reminder can also help ensure you never accidentally miss a dose or lose track of where you are in your treatment cycle.

If you notice anything after your injection — a reaction at the site, nausea, or another side effect — you can log that too, building a record that is genuinely useful to bring to your next prescriber appointment.

Ready to keep your injection schedule organised? GLP Trackr is free to start on the App Store and Google Play, with a 7-day free trial so you can see how it fits your routine before committing.

If you are curious about how to access these medicines or what the prescription process generally involves, our page on obtaining a weight loss injection covers what to expect — and for the full picture on tracking your weekly injection journey, head to our weight loss injections hub.

If you experience any side effects that feel severe, persistent, or concern you at all, contact your healthcare professional promptly. GLP Trackr helps you record your journey — it is not a substitute for your prescriber's guidance, and any decisions about your dose or treatment belong with them.