Which Injection Pens Need Pen Needles? Built-In vs Screw-On Needle Pens

You picked up a new prescription, opened the carton, and found a pen but no needle. Or you're wondering whether you need to buy needles at all. The answer depends on the device. Some pens use a separate screw-on needle for every injection, while others have a needle built in. This guide explains which injection pens need pen needles, which don't, and how to buy the right ones without guessing.

Two Kinds of Pens: Multi-Dose vs Single-Dose

Most injection pens sold in the US fall into one of two groups:

• Multi-dose pens hold several doses (or many units of insulin). You attach a new screw-on pen needle before each injection and remove it afterward. These pens need pen needles, and the needles are often not included in the carton.
• Single-dose autoinjectors deliver one dose and are then thrown away. The needle is hidden inside the device, so you don't buy or attach a separate pen needle.
• Vials are a third option for some medicines. They're used with syringes, not pen needles.

A quick test: if your pen has a threaded tip where a needle screws on, and you dial a dose, it almost certainly needs pen needles. If your device clicks once, injects automatically, and goes in the sharps container afterward, it likely has a built-in needle.

Which Injection Pens Need Pen Needles?

Pens that use separate pen needles (common US examples):

• Ozempic pen: multi-dose. US Ozempic cartons include NovoFine Plus needles, but many people keep a spare box for dropped or bent needles.
• Victoza and Saxenda pens: multi-dose pens that need pen needles.
• Zepbound KwikPen and Mounjaro KwikPen: multi-dose KwikPen versions. Lilly's instructions list a KwikPen-compatible pen needle as a supply that is not included.
• Insulin pens: Novo Nordisk FlexPen and FlexTouch pens, Lilly KwikPens and Tempo Pens, and Sanofi SoloStar pens all use screw-on pen needles.
• Reusable pens: pens like NovoPen Echo and the InPen smart pen also need pen needles.

Devices that usually don't need pen needles:

• Wegovy single-dose pen (built-in needle)
• Zepbound and Mounjaro single-dose pens (built-in needle)
• Trulicity single-dose pen (built-in needle)

Device versions can change, so your pen's Instructions for Use is the final word. If the instructions list "pen needle" among the supplies, you need them. For a closer look at one common case, see does Ozempic come with needles.

Do Pen Needles Have to Match the Pen Brand?

No. Most US insulin and GLP-1 pens share a standard screw-on connection, so a BD needle on a Novo Nordisk pen, or a NovoFine needle on a Lilly KwikPen or Sanofi SoloStar pen, is a normal pairing. Check the compatibility list on the needle box and in your pen's instructions, and ask your pharmacist if you're unsure.

Popular choices that fit most multi-dose pens:

• NovoFine Plus 32G 4mm, 100-count box: one of the shortest, thinnest pen needles sold in the US.
• BD Ultra-Fine 31G 5mm, 100-count box: a familiar short needle at a lower price per needle.

If you inject several times a day, the NovoFine Plus 2-box and 3-box value packs lower the cost per needle.

How Many Pen Needles Will You Need?

Use a new needle for every injection. Count your injections across all pens:

• Once-weekly GLP-1 pen: about 4 to 5 needles a month, roughly 52 a year. A 100-count box can last well over a year, so check the expiration date.
• One daily insulin injection: about 30 a month.
• Four daily injections: about 120 a month.

Add a small buffer for priming mistakes or dropped needles. Pen needles are generally an eligible FSA/HSA expense; check with your plan administrator.

Quick Checklist Before You Buy

• Look for a threaded tip and a dial: that pen needs pen needles.
• Check your Instructions for Use for "pen needle (not included)."
• Keep the needle length your provider recommended.
• Confirm your pen is on the needle box's compatibility list.
• Dispose of every used needle in a sharps container.

FAQ

Can I use pen needles on a single-dose autoinjector?
No. Those devices have their own built-in needle and nothing screws onto them.

My pharmacy switched me from a single-dose pen to a KwikPen. Do I need needles now?
Yes. Multi-dose KwikPens need a separate pen needle for each injection. Order them before your first dose.

Can one box of pen needles cover my insulin and GLP-1 pens?
Often, yes, if both pens are on the box's compatibility list and your provider is fine with the same length.

Shop all sizes in our pen needles collection or our pen needles for GLP-1 pens collection. New customers can use code WELCOME10 for 10% off their order.

This article is general information, not medical advice. Follow your healthcare provider's instructions for your medication, device, needle size, and injection technique.