Wegovy Injection Pens (Semaglutide)

What Is Wegovy and How Does It Work?

Wegovy is a once-weekly, prescription-only injection for weight management in adults, used alongside a reduced-calorie diet and increased activity. Its active ingredient, semaglutide, works with a natural gut hormone called GLP-1, which the body releases after eating. By acting on the appetite centres in the brain and slowing how quickly the stomach empties, it eases hunger and cravings and helps support a longer-lasting feeling of fullness, so less food is naturally needed. It also helps steady blood sugar after meals.

The dose starts low and increases gradually, and Wegovy is a long-term treatment supported by regular clinical review.

Wegovy Side Effects

The most commonly reported side effects in clinical trials were:

Side Effect	Reported In	Trial Type
Nausea	44% of patients	Clinical trials
Diarrhoea	30% of patients	Clinical trials
Vomiting	24% of patients	Clinical trials
Constipation	24% of patients	Clinical trials

 

Other side effects included abdominal pain, headache, fatigue, and dizziness.

In animal studies, semaglutide was associated with an increased risk of thyroid tumours. This link hasn’t been established in humans, but Wegovy should not be taken by anyone with a personal or family history of thyroid tumours, or a condition called MEN-2.

Other serious side effects Wegovy has been associated with other serious side effects, including acute pancreatitis, gallbladder disease, increased heart rate, and kidney injury. See the full Wegovy patient information for further detail, and seek medical advice promptly if any of these occur.

 

Directions of Use

Wegovy is a once-weekly injection given under the skin (subcutaneously), on the same day each week, at any time of day, with or without food. It can be injected into the stomach (at least 5cm from the belly button), the front of the thigh, or the back of the upper arm.

Step by Step — 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg FlexTouch Instructions

1. Wash your hands. Take the pen from the fridge and check the medicine is clear and colourless, and not past its expiry date.
2. Attach a new needle and remove the shields.
3. Choose your injection site and, if you wish, clean the skin.
4. Place the pen flat against your skin and press the dose button until the dose counter shows 0 and the clicks stop (follow your leaflet).
5. Remove the pen and put the needle straight into your sharps bin. Never reuse or share needles.

Step by Step — 7.2mg Single-Dose Pen Instructions

1. Wash your hands. Take the pen from the fridge and check the medicine is clear and colourless, and not past its expiry date.
2. Choose your injection site and, if you wish, clean the skin.
3. Pull off the pen cap. Don’t press the pen until you’re ready to inject.
4. Press the pen flat against your skin with firm pressure — this starts the injection. Keep pressing firmly until the yellow bar has completely stopped moving, then hold for a slow count of 10 before lifting the pen away.
5. Dispose of the whole pen in your sharps bin. Each pen is single-use — never reuse or share it.

Good Habits

• Rotate your injection site each week, moving at least a finger’s width from your last spot, to reduce irritation
• Take it on the same day each week — if you need to change your day, leave at least three days since your last dose
• Some redness, swelling, itching, or a small bump at the site is common and usually settles as your body adjusts; rotating sites helps
• Always follow the step-by-step instructions in your patient information leaflet and any guidance from your clinician

To learn more about using Wegovy safely, read our guide on Wegovy interactions and administration tips.

Dosage Schedule

Wegovy is started low and increased gradually, with a minimum of four weeks at each dose before increasing, over about 16-20 weeks to the maintenance dose. This helps the body adjust and keeps side effects manageable. A typical schedule:

Weeks	Dose (once weekly)	Stage
Weeks 1-4	0.25mg	Starter dose
Weeks 5-8	0.5mg	Titration
Weeks 9-12	1mg	Titration
Weeks 13-16	1.7mg	Titration
Weeks 17 onwards	2.4mg	Maintenance dose
If appropriate, and only when advised	7.2mg	Higher maintenance dose

A clinician may move more slowly if more time is needed to adjust. Most people stay on the 2.4mg maintenance dose; after at least four weeks at 2.4mg, 7.2mg once weekly may be considered, if needed, for adults with obesity. Not everyone needs to reach the top of the schedule.

Storage

Store Wegovy in the fridge (2-8°C). Once in use, the pen can be kept below 30°C or in the fridge for up to six weeks for Wegovy 0.25mg-2.4mg, and for up to 28 days for the 7.2mg pen. Keep it out of direct sunlight, don’t freeze it, and don’t use it if it has been frozen.

Frequently Asked Questions

Can I choose which day of the week I inject Wegovy?

Yes — Wegovy can be taken on any day that suits a weekly routine, as long as the same day is used consistently. If the day needs to change, at least three days should have passed since the last dose.

What should I do if I forget a dose?

Guidance on missed doses depends on how much time has passed since the scheduled dose — check the patient information leaflet or speak to a pharmacist or prescriber for guidance specific to the situation.

Is the 7.2mg pen used the same way as the lower-strength pens?

No — the 7.2mg pen is a single-dose pen with a different injection technique (pressed and held, rather than dialled and clicked), as set out in the step-by-step instructions above.

Why does Wegovy need to be started at a low dose?

Starting low and increasing gradually gives the body time to adjust to the medication, which helps keep side effects such as nausea more manageable during the early stages of treatment.