How to inject CagriReta — 7 proven steps for your first dose.

Knowing exactly how to inject CagriReta correctly matters more than for most other GLP-1 treatments, because CagriReta combines two distinct compounds — cagrilintide and semaglutide — supplied as separate vials rather than a single pre-mixed pen. This guide walks through the complete process: preparing both compounds, why they need separate injection sites, the full 7-step injection technique, rotation scheduling, needle size, storage, and the most common mistakes to avoid. Once you understand how to inject CagriReta properly, the whole process takes under ten minutes each week.

All injection technique guidance in this article follows standard subcutaneous injection principles consistent with the administration protocols used in the REDEFINE clinical trial programme studying cagrilintide and semaglutide co-administration, alongside general NHS clinical guidance. Contact our 24/7 support team with any questions before or after your first CagriReta injection.

What you need before you inject CagriReta

Gather all supplies before learning how to inject CagriReta in practice — for both compounds, you will need:

• Your cagrilintide vial — inspected and at room temperature (30 minutes out of fridge)
• Your semaglutide vial — inspected and at room temperature
• Two sterile syringes with 29 to 31 gauge, 8mm needles (one per compound)
• Four alcohol swabs — one for each vial stopper, one for each injection site
• A sharps container for safe needle disposal
• A clean cotton ball or gauze pad
• A record of your last injection sites for rotation purposes

Why separate injection sites matter

Understanding how to inject CagriReta correctly starts with understanding why the two compounds are kept apart. Cagrilintide and semaglutide are typically supplied as two separate vials, since CagriReta is not currently a single, commercially approved fixed-dose combination product. Injecting each compound at a separate site — at least 2 inches (5cm) apart — ensures both are absorbed correctly and avoids any uncertainty about combined effects at a single local tissue site. A practical approach many patients use is the abdomen for one compound and the front of the thigh for the other, keeping the routine simple and easy to remember week to week.

7 proven steps to inject CagriReta

Step 1: Remove both vials from the fridge 30 minutes before

Allow both your cagrilintide and semaglutide vials to reach room temperature for 30 minutes before injecting. Cold solutions sting more at the injection site. Never accelerate warming with heat or warm water — let both vials warm naturally side by side.

Step 2: Wash hands and prepare supplies for both compounds

Wash hands thoroughly with soap and water for at least 20 seconds. Lay out two complete sets of supplies — one for each compound — on a clean, flat surface to avoid mixing up syringes mid-process. Check each vial: the solution should be clear, colourless or very slightly yellow, with no visible particles or cloudiness. If either solution looks unusual, do not use it and contact our support team.

Step 3: Clean each vial and draw both doses

Wipe the rubber stopper of each vial with a fresh alcohol swab and allow to dry for 10 to 15 seconds. Draw air into each syringe equal to its dose volume, inject the air into the corresponding vial to prevent a vacuum, then invert and draw the medication slowly to avoid bubbles. Tap each syringe gently to move air bubbles to the top and expel them before proceeding. Keep the two syringes clearly separated and labelled in your mind — drawing both at once before injecting either keeps the whole process efficient.

Step 4: Clean both injection sites

Using a fresh alcohol swab for each, clean both injection sites in a circular motion from the centre outward. Allow each to dry completely for 10 to 15 seconds before injecting. Select sites at least 2 inches apart based on your rotation schedule — for example, the right side of your abdomen for cagrilintide and the left thigh for semaglutide, checking your injection log first.

Step 5: Inject the first compound

Pinch a fold of skin firmly, insert the needle at 45 to 90 degrees depending on your body fat level, and depress the plunger slowly over 5 to 10 seconds. Hold the needle in place for 10 seconds after the dose is complete before withdrawing — this is a frequently missed step in learning how to inject CagriReta correctly, and withdrawing too quickly can cause dose leakback through the puncture site.

Step 6: Inject the second compound at the separate site

Move to your second, pre-selected site at least 2 inches from the first. Repeat the same process — pinch, insert, inject slowly, hold for 10 seconds, withdraw smoothly. Apply gentle pressure with a clean cotton ball at each site afterwards; a small drop of blood is normal at either location.

Step 7: Dispose safely and log both injections

Place both used needles and syringes directly into your sharps container — never recap, bend, or dispose of needles in household waste. Record the date, both doses, and both injection sites in your log. This dual record-keeping is essential for proper rotation when managing two compounds simultaneously, and takes only a few extra seconds once it becomes routine.

How to inject CagriReta — rotation schedule

Site rotation is especially important when learning how to inject CagriReta, since you are injecting two compounds weekly rather than one — doubling the total injection load on your tissue over time. A practical four-week rotation across both compounds:

• Week 1: cagrilintide — right abdomen; semaglutide — left thigh
• Week 2: cagrilintide — left abdomen; semaglutide — right thigh
• Week 3: cagrilintide — right thigh; semaglutide — left abdomen
• Week 4: cagrilintide — left thigh; semaglutide — right abdomen
• Week 5: return to week 1 pattern — each site has had time to recover

Move at least 2.5cm from any previous injection point within the same general area, and keep a written or app-based log of both compounds’ sites and dates each week. This mirrors the rotation discipline recommended by the Diabetes UK injection site guidance for any regular subcutaneous treatment.

Needle size for CagriReta injections

Use a fresh needle for each compound at each injection — never reuse a needle between cagrilintide and semaglutide or across weeks.

How to inject CagriReta correctly — storage matters too

• Unopened vials (both compounds): refrigerate at 2 to 8°C in original packaging
• After reconstitution: both cagrilintide and semaglutide solutions should remain refrigerated and be used within 28 to 30 days. Label each vial with the date first reconstituted
• Never freeze either compound: frozen peptides are permanently structurally compromised and must be discarded — freezing cannot be reversed
• Avoid freeze-thaw cycles entirely for both reconstituted solutions, which significantly compromise peptide stability
• Travelling: use an insulated medical travel wallet with a buffered ice pack for both vials, never placing ice directly against either

Common CagriReta injection mistakes to avoid

• Injecting both compounds at the same site — always keep them at least 2 inches apart
• Mixing up which syringe contains which compound — label clearly or prepare and inject one fully before drawing the second
• Withdrawing the needle too quickly — always hold for 10 seconds after completing each injection
• Injecting into cold medication — allow 30 minutes at room temperature for both vials
• Reusing needles between compounds — always use a fresh sterile needle for each injection
• Doubling up after a missed dose — if 5 or more days have passed since a missed dose, skip it entirely and resume the following week rather than injecting extra
• Inconsistent rotation tracking — with two compounds to manage, a simple log is essential to avoid repeatedly using the same site

Browse our full product range and see our other injection guides for Mounjaro, Ozempic, and Retatrutide. For background on CagriReta itself, see our CagriReta weight loss results guide.