Using the Wegovy Auto-Injector Pen: Step-by-Step Injection Guide

Your first Wegovy injection day arrives and the pen is in your hand. The steps feel long, and you are not sure what "hold until the second click" actually means in practice.

This guide walks you through every step, from getting the pen ready to disposing of it safely. It also covers what happens to your pen in tropical heat, how to carry it on a boat day, and when to restart after a supply gap mid-trip. If you are on a dose escalation schedule and travelling through Samui, or if you are starting fresh and want to get the technique right from day one, the steps below are the same ones we use when supporting patients at Doctor Samui’s GLP-1 service.

Before You Inject: Preparing the Pen

Take the pen out of the fridge and let it sit at room temperature for around 30 minutes. Cold medication makes the injection more uncomfortable. Do not shake the pen. Do not warm it under hot water.

Check the solution through the window on the pen. It should be clear and colourless. If it looks cloudy, discoloured, or contains visible particles, do not use it. Use a new pen.

Remove the pen cap by pulling it straight off, not by twisting. Some pens have a small paper pull-tab under the cap: remove that too. Do not remove the needle cap until you are at the injection site and ready to go.

Choosing Your Wegovy Injection Site

Wegovy is a subcutaneous injection, meaning it goes into the fatty tissue just under the skin. The three approved sites are the abdomen at least 5 cm from your belly button, the front of the thigh, or the outer upper arm.

Absorption is equivalent across all three sites. Choose whichever feels most comfortable. The abdomen is easiest to manage on your own. The upper arm works well if someone else is helping.

Clean the skin with an alcohol swab and let it dry fully before injecting. Injecting through damp skin increases discomfort.

Injection Site Rotation: Why It Matters

Using the exact same spot every week can cause lipohypertrophy: a build-up of firm, lumpy tissue under the skin. Injecting into those areas affects how well the medication absorbs.

The fix is simple. Move at least 5 cm from your previous injection spot each time. You can rotate within the same body area or switch areas entirely. Avoid skin that is bruised, red, scarred, or actively irritated. If you have been snorkelling at Chaweng or Lamai and the skin is sunburned, choose a different site.

Step-by-Step Wegovy Auto-Injector Instructions

Step one: with the needle cap still on, place the pen against your chosen site at a 90-degree angle. Press firmly so the pen tip is in good contact with the skin.

Step two: while pressing the pen against the skin, press the injection button with your thumb. You will hear and feel the first click. This means the injection has started. Keep the pen pressed against your skin. Do not lift it.

Step three: keep holding the pen in place. The yellow indicator in the window will move as the medication delivers. When the yellow bar stops moving and you hear the second click, the injection is complete.

Step four: remove the pen from your skin. A small drop of blood or a red mark is normal. Apply gentle pressure for a few seconds. Do not rub the site.

Step five: replace the outer needle cap and dispose of the pen in a sharps container. Never push the cap back onto the needle using your fingers.

Storing Your Wegovy Pen in Koh Samui’s Heat

This is where tropical travel creates a specific problem. Wegovy must be stored between 2°C and 8°C in a refrigerator until first use. Once removed from the fridge, it must be kept below 30°C and used within 28 days.

On Koh Samui, ambient temperatures regularly exceed 30°C in a parked car, a beach bag in direct sun, or a hotel room with the air conditioning off. A pen exposed to temperatures above 30°C may have degraded semaglutide. It can look completely normal and still be ineffective.

Keep the pen in your hotel minibar or fridge when you are not using it. If you are heading out on a day trip to Angthong or a boat excursion from the coast, carry the pen in an insulated cool bag with a gel pack. Never leave it in a vehicle. If you are not sure whether your pen overheated, do not guess: come into Doctor Samui or contact your prescriber. A degraded pen means an ineffective dose, not just a wasted one.

Travelling with Your Wegovy Pen: Practical Tips for Samui

Flying into Samui with your pen? Keep it in your carry-on luggage, never in checked baggage. Cargo holds can drop below freezing, and extreme cold damages the medication just as extreme heat does. Airport security allows injectable medications with a prescription label or a doctor’s letter.

If you are island-hopping or taking a ferry from the mainland, carry the pen with you and keep it insulated throughout. A small medical cool pouch works well and does not draw attention at checkpoints.

For longer stays, check that your supply covers the full trip. Wegovy is not always available at every pharmacy in Thailand. If you run short or need support adjusting your schedule around travel, our GLP-1 page has details on what we can help with on the island.

What to Do If Your Pen Does Not Click or Inject Correctly

The most common reason the pen does not click: you are not pressing it firmly enough against the skin, or the skin surface is not firm enough. Press harder. Try pinching a small fold of skin before placing the pen.

If the yellow indicator bar does not move after the first click, the injection has not completed. Keep the pen pressed against your skin. Wait a few more seconds. If the bar still does not move and you do not hear a second click, remove the pen, apply gentle pressure, and use a new pen. Do not attempt to re-inject from the same pen into the same spot.

If you have any doubt about whether the full dose was delivered, do not inject again. Contact your prescriber. Taking a double dose in one week is not safe.

What to Do If You Miss a Wegovy Dose

If you remember your missed dose and your next scheduled injection is still more than 2 days away, take the missed dose as soon as you remember. Then return to your normal weekly schedule from that point.

If your next scheduled injection is less than 2 days away, skip the missed dose. Resume your normal weekly schedule on the next planned injection day. Do not take two doses to compensate.

If you have been off Wegovy for several weeks due to travel delays or a supply issue, do not restart at your previous dose without checking first. You may need to re-escalate from a lower dose. Speak to your prescriber or come in to Doctor Samui before restarting.

When to Get Medical Support

Mild redness, a small bruise, or brief soreness at the injection site are normal. They usually settle within a day or two.

Wegovy is not suitable for people with a personal or family history of medullary thyroid carcinoma or a condition called MEN2, and should be used with caution by people with a history of pancreatitis. Speak to a doctor before starting if any of these apply to you. See a doctor if you notice a raised, painful lump that does not settle, spreading redness or warmth around the site, or if you develop severe nausea, persistent vomiting, or significant abdominal pain. In Koh Samui’s heat, GI side effects from semaglutide can combine with dehydration faster than they would in a cooler climate. Staying well-hydrated matters more here. If you need a consultation, a prescription review, or reassurance about your injection technique, you can walk into the Chaweng clinic or book a hotel visit across the island.