This article is for general education and is not medical advice. Always follow the instructions that came with your specific pen and confirm compatibility with your pharmacist if you're unsure.
We covered Ozempic and Wegovy compatibility in an earlier guide. Here's the same breakdown for the other GLP-1 and related pens people write in about most: Mounjaro, Trulicity, Victoza, and Byetta.
First, the key distinction: reusable pens vs. single-use autoinjectors
GLP-1 and insulin pens fall into two broad categories, and it changes everything about which needles apply:
- Reusable/durable pens take a separate, replaceable screw-on or click-on needle for every injection. These are the pens this article — and needle shopping in general — applies to.
- Single-use prefilled autoinjectors have the needle built in and hidden inside the device. You don't attach or buy a needle for these; the whole pen is disposed of after use.
Mounjaro (tirzepatide)
Mounjaro is typically supplied as a single-use prefilled pen with the needle built in and hidden — similar in concept to a Wegovy autoinjector. You do not attach a separate needle to a standard Mounjaro pen.
Trulicity (dulaglutide)
Trulicity is also supplied as a single-use prefilled autoinjector with a concealed, non-removable needle. As with Mounjaro, there's no separate needle to buy for the standard Trulicity pen.
Victoza (liraglutide) and Saxenda (liraglutide)
Unlike Mounjaro and Trulicity, Victoza and Saxenda pens are reusable, multi-dose pens that require a separate, replaceable pen needle for every injection — the same category as Ozempic. Because these pens use the same universal screw-thread connection, standard 32G 4mm pen needles (NovoFine Plus, BD Nano, and similar) are generally compatible. Check your pen's specific instructions to confirm.
Byetta (exenatide)
Byetta is a reusable pen that takes a separate screw-on needle, similar to Ozempic, Victoza, and Saxenda. Standard universal-fit pen needles are generally compatible.
Quick reference table
| Medication | Pen type | Needle needed? |
|---|---|---|
| Ozempic | Reusable, multi-dose | Yes — universal-fit needle (32G 4mm supplied) |
| Wegovy | Single-use autoinjector | No — built in |
| Mounjaro | Single-use autoinjector | No — built in |
| Trulicity | Single-use autoinjector | No — built in |
| Victoza / Saxenda | Reusable, multi-dose | Yes — universal-fit needle |
| Byetta | Reusable, multi-dose | Yes — universal-fit needle |
Not sure which category your pen falls into? Look at the device itself: if there's a visible needle cover you remove and a needle you screw on before each dose, it's a reusable pen. If the entire device is disposed of after one injection and you never see or attach a needle, it's a single-use autoinjector.
Why some manufacturers moved to autoinjectors
Single-use autoinjectors remove a few user steps — no attaching, priming, or disposing of a separate needle — which some people find simpler. The tradeoff is less flexibility in choosing needle gauge or length, since that decision is built into the device by the manufacturer rather than left to the user.
If you have a reusable pen: what to buy
For Ozempic, Victoza, Saxenda, Byetta, and other reusable multi-dose pens using the universal screw-thread standard:
- NovoFine Plus 32G 4mm – 100 Count — the most common default
- BD Nano 2nd Gen 32G 4mm – 100 Count
- BD Ultra-Fine 31G 5mm – 100 Count
Not sure which length or gauge is right? See our complete buying guide, or the detailed length and gauge comparisons.
Frequently asked questions
Do I need to buy needles for my Mounjaro pen?
No. Standard Mounjaro pens are single-use autoinjectors with the needle built in and hidden — there's no separate needle to attach or buy.
Can I use the same needles for Ozempic and Victoza?
Both are reusable pens using the universal screw-thread standard, so the same compatible needles (like 32G 4mm) generally work for both — though you should always confirm with your pen's instructions.
Why doesn't Trulicity need a separate needle but Ozempic does?
They're different device designs. Trulicity is built as a single-use autoinjector with the needle concealed inside; Ozempic is a reusable multi-dose pen that requires attaching a new needle before each injection.
How do I know which category my specific pen is?
Check your medication's patient information leaflet, or look at the device: a removable needle you attach yourself means a reusable pen; no visible needle and single-dose disposal means an autoinjector.
Educational content only — not medical advice. Product names are trademarks of their respective owners. Last reviewed: August 2026.
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