Encyclopedia entry
Pen vs vial GLP-1 delivery
UK licensed GLP-1 medications are delivered to patients in two formats: pre-filled multi-dose pens (KwikPens) and single-use pre-filled vial-and-syringe formats. The format affects dose precision, ease of use, packaging waste, and storage logistics. Current UK Mounjaro delivery shifted from vials to KwikPens during 2024 to 2025.
Pre-filled pens
- · KwikPen for Mounjaro: multi-dose pen with dial-set dose selection at 2.5, 5, 7.5, 10, 12.5, or 15 mg.
- · Wegovy FlexTouch: weekly disposable single-use pen pre-set to one of the titration doses.
- · Saxenda FlexTouch: multi-dose pen for daily injection, dial-set to 0.6 to 3 mg.
- · Advantages: ease of use, error reduction, easier travel.
- · Disadvantages: higher unit cost for the manufacturer, more plastic packaging.
Single-use vials
- · Tirzepatide single-use vial format: still available in the US through some compounding sources; not the current UK route.
- · Advantages: cheaper unit cost, theoretical dose flexibility.
- · Disadvantages: requires the patient to draw up the dose accurately each time, increases dose-error risk, more clinical training required.
Current UK position
Eli Lilly transitioned UK Mounjaro supply from vials to KwikPens during 2024 to 2025 to align with the rest of the UK GLP-1 market and reduce dose-error rates in real-world use. Novo Nordisk Wegovy has been pen-only in the UK since launch. Saxenda is multi-dose pen. UK pharmacies dispense whatever format is licensed; vial-format GLP-1 is not a routine UK option.
Related: cold chain · compounded vs licensed.