Pen Needles for Ozempic, Zepbound KwikPen, and Mounjaro: What Size and What Fits

Last updated October 2026. This guide is for education only. It is not medical advice.

Your GLP-1 pen showed up. The needles may not have. Or you got a few, and now you're running low.

Here's the short answer. If your pen takes separate needles, standard pen needles fit it. They're the same ones insulin pens use. Two sizes cover most adults: 32G x 4mm and 31G x 5mm. Your pharmacist can tell you which one is right for you.

The rest of this guide covers which pens need needles, what the numbers on the box mean, how to put a needle on, and how to get rid of used ones safely.

Quick answer

• Ozempic: a multi-dose pen. Needles come in the box (32G x 4mm). Buy more if you want spares.
• Zepbound KwikPen: a multi-dose pen. Needles are not included. Any standard Type A pen needle fits.
• Mounjaro KwikPen: a multi-dose pen, available in select countries including the US. Needles are not included.
• Zepbound, Mounjaro, and Wegovy single-dose pens: the needle is built in. Nothing to buy.
• Vials: you need syringes, not pen needles.
• Every pen: use a new needle for every shot.

Do GLP-1 pens need special needles?

No. There's no such thing as a "GLP-1 needle." Pens for Ozempic, Saxenda, and the Zepbound KwikPen take the same standard pen needles insulin pens use. The industry name for this fit is "Type A." If a box says it fits Type A pens, it fits these.

You'll see them called pen needles, insulin pen needles, or pen tips. Same thing. It's a small, sterile needle that screws onto the end of your pen and gets used once.

One catch: some GLP-1 pens have the needle built in. The single-dose Zepbound, Mounjaro, and Wegovy pens work this way. You press the pen to your skin, it does the rest, and the whole pen goes in the sharps container. There's nothing extra to buy.

Not sure which kind you have? Check the box or the instructions that came with it, or ask your pharmacist.

Which pens need separate needles?

There are two kinds of pens.

Multi-dose pens hold several doses. You put a new needle on for every shot. These need pen needles.

Single-dose pens hold one shot, with the needle already inside. These don't.

Here's how the common pens line up:

On a phone, swipe the table sideways to see every column.

Ozempic users: your pen comes with needles, and there should be enough for the doses in that pen. People still buy extras for a dropped or bent needle, a backup for travel, or a spare box at home.

Zepbound KwikPen users: the KwikPen is a different device from the Zepbound single-dose pen. Lilly's instructions list a "KwikPen-compatible pen needle" as something you need, and say needles aren't included. Standard Type A pen needles are that.

Mounjaro KwikPen users: the KwikPen is available in select countries, including the US. Check with your pharmacist about which Mounjaro device you were given. If it's a KwikPen, you'll need pen needles.

Compounded GLP-1s: some compounded semaglutide or tirzepatide comes in a vial. If yours did, you'll draw each dose with a syringe instead of using a pen needle. If it came in a refillable cartridge pen, that pen may take standard pen needles. Ask the pharmacy that filled it which supplies to use.

Pen needles don't need a prescription in most states.

More on the Zepbound KwikPen: Does Zepbound KwikPen come with needles? · What pen needles fit Zepbound KwikPen? · Zepbound KwikPen vs Wegovy · Medicare GLP-1 Bridge and pen needles

What the numbers on the box mean

Every box of pen needles has two numbers.

Gauge (G) is thickness. The bigger the number, the thinner the needle. A 32G needle is thinner than a 31G needle.

Length (mm) is how far it goes in. A 4mm needle is shorter than a 5mm needle.

GLP-1 medicines go into the layer of fat just under your skin. Doctors call this "subcutaneous." For most adults, a 4mm or 5mm needle reaches that layer when you go straight in, with no need to pinch the skin. Longer needles make it more likely you'll hit muscle, which can change how the medicine is absorbed.

Older lengths like 6mm, 8mm, and 12.7mm are still sold, but most adults don't need them.

Do I need a longer needle if I have a larger body? Usually not. Injection experts at the Forum for Injection Technique say a 4mm needle works for adults of any body size. Your skin is about the same thickness no matter your weight. What changes is the fat layer under it, and a 4mm needle gets into that layer either way.

Thinner needles usually feel better. That said, plenty of people can't tell a 31G from a 32G.

Pip's needles also have thin walls. That means the inside of the needle is a little wider, so medicine flows easily even through a thin needle.

What size pen needle for Ozempic, Zepbound, or Mounjaro?

Two sizes cover most adults: 32G x 4mm and 31G x 5mm. Both fit Ozempic, the Zepbound KwikPen, and the Mounjaro KwikPen.

• 32G x 4mm is the shortest, thinnest common size. It's the same size Novo Nordisk puts in the Ozempic box. Pip's "Mighty Fine" needles are this size.
• 31G x 5mm is a little longer and a touch thicker. Some people just prefer it, and some providers suggest it. Pip's "So Fine" needles are this size.

Seeing a drop of medicine on your skin after a shot? That's called leak-back. It's usually about technique, not needle length. Press the button all the way and hold the needle in for the full count your pen's instructions give before you pull it out. If it keeps happening, ask your pharmacist.

Talk to your prescriber or pharmacist before you choose if:

• you're very lean where you inject
• you've been told to use a certain size
• you often see leaking or bruising after a shot
• you're giving shots to a child or teen

Brand doesn't matter for fit. You don't need to match your needle brand to your pen brand. Pip pen needles are not made, endorsed, or approved by Eli Lilly or Novo Nordisk. They're standard pen needles made to fit standard pens.

How to put on a needle and give your shot

Your pen's instructions come first. Pens differ in small ways that matter, like when to prime and how long to hold. Here's the general routine for a multi-dose pen.

1. Wash your hands.
2. Check the pen. Make sure it's the right medicine and it isn't expired. Look at the liquid through the window. Ozempic should be clear and colorless. Zepbound KwikPen should be clear and colorless to slightly yellow. If it's cloudy or has bits in it, don't use it.
3. Put on a new needle. Peel off the paper tab. Push the needle straight onto the pen and twist until it's snug.
4. Take off both caps. Keep the big outer cap. You'll use it to remove the needle later. Throw away the small inner cap.
5. Prime, if your pen says to. Priming pushes out air and makes sure medicine is flowing. Pens differ here. Ozempic and Saxenda only need it before the first shot with each new pen. Lilly's instructions say to prime the Zepbound KwikPen before every weekly shot. You should see a drop at the needle tip. Check your pen's instructions.
6. Set your dose. Use the dose your prescriber gave you, set the way your pen's instructions show. This guide doesn't cover dosing.
7. Pick your spot. Common spots are the stomach (at least 2 inches from your belly button), the front or outer thigh, and the back of the upper arm. Use a different spot each time.
8. Inject. Put the needle straight in. Press the button all the way and keep holding it. Hold time depends on the pen. Ozempic says to count slowly to 6 after the counter hits 0. The Zepbound KwikPen says to count slowly to 5. Follow yours.
9. Take the needle off. Put the big outer cap back on, unscrew the needle, and drop it in your sharps container.
10. Put the pen cap back on. Store the pen the way your instructions say, and never with a needle attached.

Common mistakes to skip

Reusing needles. A used needle is duller, so the next shot hurts more. It can bend, clog, or carry germs, and a clogged needle can throw off your dose. Needles are cheap. This isn't the place to save.

Storing the pen with the needle on. Medicine can leak out and air can get in. Take the needle off after every shot.

Using the same spot every time. Over months, this can cause lumpy, thickened skin that soaks up medicine more slowly. Move to a new spot each time.

Buying by price alone. A 6mm x 29G needle is much longer and thicker than a 4mm x 32G, and it can cost the same. Check both numbers on the box.

How to get rid of used needles

Used pen needles are "sharps." They need a safe home.

• Use a sharps container. You can buy one at a pharmacy or online.
• No container yet? A heavy plastic bottle with a screw-on lid, like a laundry detergent bottle, works in many areas. Label it "Sharps: do not recycle" and keep it away from kids and pets. Check your local rules.
• Never put loose needles in the trash or recycling. They can stick sanitation workers and anyone who handles your garbage.
• Find a drop-off or mail-back program. Many pharmacies, hospitals, and health departments take full containers. Search "[your county] sharps disposal" to find one near you.
• On the go? Pack a small travel sharps container so you never have to carry a loose used needle.

Why people buy pen needles from Pip

• Fits standard pens. Pip pen needles fit Type A pens, including Ozempic, the Zepbound KwikPen, the Mounjaro KwikPen, and most insulin pens. No adapter needed.
• Two sizes, one price. 32G x 4mm or 31G x 5mm. $13.99 for a box of 100.
• Made for smooth shots. Thin walls for easy flow. Each tip has three polished bevels (angled cuts) to slide in cleanly. Every needle is sterilized and checked by a high-speed camera before it ships.
• FSA and HSA eligible. Use your card at checkout.
• Free shipping on orders over $25. Standard shipping takes 3 to 4 days. Not happy? Return it within 30 days for a full refund.
• 670+ reviews from people who use them every week.

Rather buy in person? Pip pen needles are available at Good Neighbor Pharmacies nationwide. They're stocked through Cencora, one of the largest pharmaceutical wholesalers, so any pharmacy that orders through Cencora can get them. Just ask your pharmacist, or find a store near you.

Shop Pip Pen Needles →

Round out your kit with alcohol prep pads. See the full GLP-1 injection starter kit checklist.

Frequently asked questions

What size pen needle is best for Ozempic?

For most adults, 32G x 4mm. That's the size that comes in the Ozempic box. Some people prefer 31G x 5mm. The Ozempic instructions say compatible needles up to 8mm can be used. Ask your pharmacist which is right for you.

Does Ozempic come with needles?

Yes. Each Ozempic pen comes with NovoFine Plus 32G x 4mm needles. If you want extras, standard Type A pen needles fit.

Do Zepbound KwikPens come with needles?

No. Lilly's instructions say needles aren't included with the KwikPen. Any standard Type A pen needle fits. The single-dose Zepbound pen is different: its needle is built in.

What needles fit a Zepbound KwikPen?

Any standard Type A pen needle. You don't need a Zepbound-branded needle. Pip's 32G x 4mm and 31G x 5mm needles both fit.

Do you need pen needles for Mounjaro?

It depends on your device. The single-dose Mounjaro pen has a built-in needle, so you don't need any. The Mounjaro KwikPen, available in select countries including the US, takes standard pen needles. Check with your pharmacist about which one you have.

Can I use insulin pen needles for Mounjaro or Zepbound?

Yes, if you have a KwikPen. Insulin pen needles and "GLP-1 needles" are the same product.

Is 31G or 32G better?

32G is a little thinner, so many people find it more comfortable. 31G is a little thicker. The difference is small, and plenty of people can't feel it.

Do I need a longer needle if I have a higher BMI?

Usually not. Injection experts say a 4mm needle reaches the fat layer under the skin for adults of any body size. Longer needles raise the chance of hitting muscle. Ask your care team if you're unsure.

Can I reuse a pen needle?

No. Pen needles are made for one use. A reused needle is duller and can bend, clog, or carry germs. Use a new one every time.

What if my GLP-1 came in a vial?

You'll need syringes, not pen needles. Ask the pharmacy that filled your prescription which syringe to use.

Do all pen needles fit all pens?

Almost all. Standard Type A pen needles fit nearly every insulin and GLP-1 pen that takes separate needles. Pens with a built-in needle don't take separate needles at all.

Are Pip pen needles FSA and HSA eligible?

Yes. You can pay with your FSA or HSA card at checkout.

Where can I buy pen needles for Ozempic or Zepbound?

At most pharmacies and online, usually without a prescription. You can order from hellopip.com (100 needles for $13.99, free shipping on orders over $25), or ask for Pip at a Good Neighbor Pharmacy.

Want more detail on sizes? See our lancet and pen needle size guide and the ultimate guide to pen needles and insulin syringes.

Sources

• Novo Nordisk, Ozempic Prescribing Information and Instructions for Use
• Lilly, Zepbound KwikPen U.S. Instructions for Use
• Lilly, Zepbound KwikPen needle compatibility FAQ
• Novo Nordisk, Saxenda Prescribing Information and Instructions for Use
• FDA, Sharps Disposal Containers
• Frid AH, et al. New Insulin Delivery Recommendations (Forum for Injection Technique). Mayo Clinic Proceedings, 2016

Medical disclaimer: This article is for education only. It isn't a substitute for advice from your doctor, nurse, or pharmacist. Always follow the instructions that came with your medicine, and ask your prescriber or pharmacist about needle size, how to inject, and any questions about your treatment. In an emergency, call 911.

Trademarks: Zepbound, Mounjaro, KwikPen, and Humalog are registered trademarks of Eli Lilly and Company. Ozempic, Wegovy, Saxenda, NovoFine, and NovoLog are registered trademarks of Novo Nordisk A/S. Lantus is a registered trademark of Sanofi. Pip is not affiliated with, endorsed by, or sponsored by Eli Lilly, Novo Nordisk, or Sanofi.