Taking Wegovy for the first time: a step-by-step guide

Step 1: before you inject, preparation and what to check

Take the Wegovy pen from the fridge and let it sit at room temperature for around 30 minutes before you inject. Cold medicine going in can sting more than it needs to. Wash your hands thoroughly with soap and water first. Then look at the pen: the liquid should be clear and colourless or faintly yellow. If it looks cloudy, discoloured or contains particles, do not use it, contact your prescriber or our support team for advice.

Check the expiry date on the label. A common misconception is that the pen can be left out on the worktop indefinitely once you've started the box, it can't. The exact room-temperature storage window is printed in your Patient Information Leaflet; follow that, not anything else you've read online. Store unused pens in the fridge at 2–8 °C.

Clean the injection site with an alcohol swab and let the skin dry completely before injecting. Wet skin can cause mild stinging and may affect how cleanly the needle enters. Attach a fresh needle to the pen just before you use it, following the instructions in the leaflet, the needle is not pre-attached when the pen is supplied.

Step 2: the injection itself

Pinch a fold of skin gently at your chosen site. Hold the pen firmly against the skin at a 90-degree angle, press the injection button, and keep the pen held in place until the dose counter returns to zero. The Wegovy pen's injection mechanism is designed to be straightforward, but it does take a moment to deliver the full dose, releasing early means you may not receive it all. Most people find the injection itself is much less uncomfortable than they expected. If you want a full walkthrough before you begin, our guide on how to use Wegovy for the first time takes you through every step in detail.

After the click that signals delivery, remove the pen from the skin. A small amount of bleeding or redness at the site is common and settles quickly. Remove the needle immediately after each use without re-capping it, and place it directly into a sharps container, never into household waste. Keep the pen cap on when it's stored in the fridge.

The NHS patient information for semaglutide is a reliable and straightforward resource if you want to read through the full instructions independently; we'd encourage you to.

Step 3: choosing your injection day and site rotation

Wegovy is injected once a week. If you are unsure when to schedule your doses, our page on the best time to take your Wegovy injections explains the practical factors worth considering, including how time of day and routine can affect how well you stick with treatment. Write it in your phone calendar or set a reminder for the first few weeks until it becomes habit.

Rotate your injection site each week. If you use your abdomen this week, use your thigh next week, then your upper arm the week after. Returning to the same spot repeatedly can lead to localised skin changes over time. Within each site, vary the exact spot slightly, a few centimetres from where you injected last time works well.

Avoid injecting into skin that is bruised, sore, red or broken. Don't inject into muscle; the subcutaneous tissue (the soft layer just beneath the skin) is where the medicine is absorbed correctly. If you're unsure about technique after reading the leaflet, ask our prescribers directly. That's what aftercare is for.

What to expect in the first few weeks

Nausea is the most commonly reported side effect when starting Wegovy, and it tends to be most noticeable in the first day or two after each injection, particularly after dose increases. Eating smaller, lighter meals (less fatty and less spicy than usual) helps many people get through this phase more comfortably. Staying well hydrated matters too. For most people the nausea settles significantly within a couple of weeks as the body adjusts.

Other side effects reported in clinical trials (the STEP 1 study involved nearly 2,000 adults and is published in full in the New England Journal of Medicine) include constipation, diarrhoea, headache and fatigue. These are typically mild to moderate. Serious side effects are uncommon but include pancreatitis: if you develop severe stomach pain that spreads toward your back, seek medical attention promptly. The NHS medicines page for semaglutide lists the full side-effect profile and the signs that need urgent review.

What won't happen in week one: dramatic weight loss. The starting dose is a tolerability dose. Weight-related changes usually become noticeable after several months, as the dose is increased step by step under prescriber supervision. If you are considering what Wegovy might cost over a course of treatment, our guide to where and how to access Wegovy covers private pricing context and what a legitimate prescription service includes.

Once you feel settled with the process, our detailed overview of how to take Wegovy covers ongoing use, missed doses and what changes as you move through the dose schedule. Your prescriber is the right person to guide titration timing, never adjust your dose based on how you feel without checking first.