Your first injection

Almost everyone is nervous about the first one. Almost everyone reports afterwards that it was less of an event than they expected — the needle is short and fine, and it goes into the fat just under the skin rather than into muscle.

Here is the whole thing, start to finish. Your programme will send its own instructions and those take priority over anything on this page; this is what the process generally looks like.

1. Take it out of the fridgeLet it sit for 15 to 30 minutes. A cold injection stings more than a room-temperature one. Do not warm it in hot water or a microwave.
2. Wash your hands, then check the vial or penThe liquid should be clear and free of particles. If it looks cloudy or discoloured, do not use it — message your provider.
3. Pick your spotAbdomen at least two inches from the navel, the front of the thigh, or the back of the upper arm. Rotate each week so you are not using the same patch repeatedly.
4. Clean the skin and let it dryAn alcohol wipe, then wait for it to air-dry. Injecting through wet alcohol is what makes it sting.
5. Pinch, insert, injectPinch a fold of skin, insert the needle at 90 degrees, press the plunger steadily, and count to five before withdrawing so the full dose goes in.
6. Dispose of the needle properlyStraight into a rigid sharps container. Never recap, never into household rubbish.
7. Write down the date and doseA note on your phone is enough. You will want the record when a clinician asks, and it makes a missed week obvious.

What it feels like afterwards

Usually nothing much at the site — occasionally a small red mark or a bit of itch for an hour. The systemic effects, if they come, arrive over the following day or two rather than immediately.

Nausea, diarrhoea, constipation and reflux, concentrated in the weeks after each dose increase. That is tirzepatide. For semaglutide: Nausea, vomiting, diarrhoea and constipation, usually worst in the first weeks and after dose increases.

What is typical and what is not is set out in side effects, week by week.

When to call somebody

• Severe or persistent abdominal pain, particularly if it radiates to your back.
• Vomiting that stops you keeping fluids down.
• Signs of an allergic reaction — swelling of the face or throat, difficulty breathing.
• Anything that frightens you. A programme that makes you feel silly for asking is the wrong programme.

This is general information, not medical advice. Follow the instructions your prescriber gives you, and in an emergency call your local emergency number.

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