Where & how to inject your GLP-1 medication
A SengMed how-to guide · Reviewed by our clinical team
Most GLP-1 weight loss medications come as a pre-filled pen that you inject under the skin (subcutaneously) once a week. The technique is simple once you’ve done it a few times. This guide walks through where to inject, how to do it, and how to stay comfortable and safe.
This guide is general information, not medical advice. Always follow the instructions from your SengMed doctor and the leaflet supplied with your specific medication. If anything is unclear, message your care team before injecting.
Where to inject
GLP-1 pens are designed for subcutaneous injection — into the fatty layer just under the skin. Three areas work well:
- Abdomen (tummy) — anywhere except a 5 cm circle around your navel. This is the most popular site and easy to reach.
- Front of the thigh — the upper, outer area of the thigh.
- Back of the upper arm — the fatty area; usually easiest if someone helps you.
Avoid injecting into skin that is bruised, tender, red, hard, or scarred, and avoid areas affected by stretch marks.
Rotating your injection site
Inject into the same general area each week if you like, but move to a different spot within that area each time — at least 2–3 cm from your last injection. Rotating sites helps prevent lumps and skin changes that can affect how the medication is absorbed.
Step by step
- Wash your hands with soap and water.
- Take the pen out of the fridge. Letting it sit for a few minutes so it’s not ice-cold can make the injection more comfortable.
- Check the medication — it should be clear and colourless. Don’t use it if it looks cloudy or contains particles, or if the pen is damaged.
- Attach a new needle and complete the flow/safety check if your pen requires one (see your leaflet).
- Dial your prescribed dose.
- Clean the skin with an alcohol swab and let it dry.
- Pinch the skin gently if advised, insert the needle, and press the dose button fully.
- Hold for about 6 seconds (or as your leaflet states) so the full dose is delivered, then withdraw the needle.
- Dispose of the needle straight away in a sharps container.
Staying comfortable
- Inject at room temperature rather than straight from the fridge.
- Let the alcohol swab dry fully before injecting — wet skin stings more.
- Relax the muscle in the area; tension can make it feel sharper.
- A small amount of redness or a tiny drop of blood afterwards is normal.
Safe sharps disposal in Singapore
Never put used needles in your household rubbish or recycling. Use a proper sharps container (or a puncture-proof, sealable rigid container) and keep it out of reach of children. Many pharmacies and polyclinics in Singapore accept full sharps containers for safe disposal — ask your SengMed care team or partner pharmacy where to return yours.
When to contact your doctor
Message your SengMed care team or seek medical advice if you notice:
- A skin reaction that spreads, worsens, or doesn’t settle.
- A hard lump at injection sites that doesn’t go away.
- Signs of an allergic reaction such as rash, swelling, or difficulty breathing — for severe symptoms, call 995 immediately.