A Guide to Injecting GLP-1s

Here’s an overview of the injection process for Wegovy, Mounjaro, Ozempic and Saxenda.

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Before you start a GLP-1 medication, you should read the step-by-step usage instructions that come with it and/or watch the video tutorials on the drug manufacturer website. But, to give you a sense of what to expect, here’s an overview of the injection process — with some tips from Trey Tietz, a pharmacy manager at the Cleveland Clinic and Sunrise’s Pharmacy Advisor.

This guide discusses injectable brand-name GLP-1s: Wegovy and Ozempic (both semaglutide), Mounjaro (tirzepatide), and Saxenda (liraglutide). Differences between the four medications are noted. Another tirzepatide medication, Zepbound, was recently approved by the FDA for weight loss and is expected to be available soon. The injection instructions should be similar to those for Mounjaro, but we won’t know until it hits the market.

1. Get familiar with your injector pens and store them properly

GLP-1s are dispensed as prefilled injector pens. Each one looks a little different. 

  • Both Wegovy and Mounjaro pens are single-use. A one month supply of medication contains four pens. 
  • Ozempic pens each contain multiple doses and come with a set of needles. The lower-dosage pen contains between four and eight doses of medication, whereas the higher-dosage pen contains four doses. (Your doctor will provide dosage instructions.) No matter what, you’ll reuse the same pen for at least one month before throwing it out, and it’s important to attach a new needle for each injection. Never reuse a needle. 
  • Saxenda is a daily medication. Each pen contains at least six doses and comes with a set of needles. 

New, unused injector pens can be stored in the refrigerator until they reach their expiration date, which is printed on the back of each pen. 

Unused Wegovy and Mounjaro can be stored at room temperature for a limited amount of time:

  • Unused Wegovy can stay at room temperature for up to 28 days.
  • Unused Mounjaro can stay at room temperature for up to 21 days.

Unused Ozempic and Saxenda pens must be refrigerated. Once you open these pens, they can be refrigerated or stored at room temperature. Either way, they need to be thrown out after a certain amount of time:

  • Ozempic pens last 56 days after being opened, regardless of how they’re stored.
  • Saxenda pens last 30 days after being opened, regardless of how they’re stored.

For all GLP-1s, Tietz advises storing injector pens in their original carton to protect the medication from light exposure.

2. Choose your injection day (or time of day)

Wegovy, Mounjaro and Ozempic are all weekly medications, and they should be taken on the same day each week. They don’t need to be taken at the same time of day for the medication to work, but Tietz recommends setting a calendar reminder or phone alarm for the same time of day anyway — as a precaution to avoid forgetting a dose.

It’s smart to consider your schedule when choosing an injection day. One thing to keep in mind: If you experience side effects from your medication, they usually happen the day after an injection (not the day of). So avoid starting it the day of, or day before, a big presentation at work just in case.

Saxenda should be taken at the same time each day (try to stay within a one-hour window). Tietz recommends morning injections so the medication lasts all day. 

3. Gather your supplies and check your pen

For every injection, you’ll need: Your injector pen, an alcohol wipe, a clean cotton ball or piece of gauze, and a sharps container. For Ozempic and Saxenda injections, you’ll also need a new needle.

Look through the pen window to make sure your medication is clear and colorless. If it isn’t, don’t use that pen.

4. Choose your injection site

GLP-1s are injected subcutaneously, meaning just under your skin. The abdomen is the most popular injection site, followed by the thigh, says Tietz. But you can use your butt or the back of your upper arm too — as long as there’s enough tissue that you can’t accidentally inject into a muscle. If you use these locations it's better to have a friend or family member give you the shot.

You’ll want to rotate the injection site to avoid developing a site reaction, such as bruising, a rash, general discomfort in the area, or bumps underneath the skin. You can keep using the same general body area as long as you move the pen to a different spot. If you’re injecting into your stomach, you can use the “clock method”: Think of your belly button as the center of the clock and move one hour on the clock each time you inject. But don’t inject your belly button. A good rule of thumb is to place your pen at least two finger widths away. 

For Wegovy specifically, Tietz says, the thigh might be an easier injection site than the stomach because you’ll need to apply some force to administer the shot.  

5. Clean the injection site

Once you know where you’re injecting, sterilize the area with an alcohol wipe. 

6. Prepare the injection

For Wegovy, just pull off the pen cap and throw it out. Mounjaro is similar, but the pen has a lock. Pull off the cap in the locked position and throw it out. 

For Ozempic and Saxenda, injection prep is a bit more involved: You’ll need to attach a new needle to the pen; remove two caps (throwing out the inner cap and holding onto the outer cap); check the medication flow with the dose counter and selector if it’s the first time you’re using a new pen; and then select your dose. 

You can find detailed illustrated instructions for Ozempic on page 10 of the medication manual. For Saxenda, go to page 11.

7. Position the pen

Place the pen flush against dry, sterilized skin.

For Mounjaro, turn the ring to unlock the pen. For Ozempic and Saxenda, insert the needle into your skin.

If possible, also try to position the pen so you can see the pen window (which shows how much medication is left). But, if you inject into your thigh and the pen window is out of view, don’t stress. It’s helpful to be able to see it, but it’s not critical.  

8. Inject the medication

For Wegovy, firmly press the whole pen down — you’ll need to apply some pressure. For Mounjaro, just press the injection button on top of the pen. For both of these medications, you’ll hear two clicks: The first one tells you the injection is starting. Once you hear the second click, count to 10 before removing the pen. (Don’t remove it immediately or you might miss some medication.) Both pens also have visual indicators that you’re done injecting. For Wegovy, a yellow bar will stop moving when the injection is finished. For Mounjaro, there’s a gray plunger.

For Ozempic and Saxenda, press the button on top of the pen and hold it down. You will hear clicks as the medication is being administered. Hold the button down until the dose counter says “0” and/or you stop hearing clicks (if you’re injecting in your thigh and can’t see the counter). Then count to six before removing the pen. 

For any medication, if blood appears at the injection site, press down gently with a gauze pad or cotton ball.

9. Throw out your sharps

For single-use pens, throw out the entire pen after you’re done injecting. For multi-use pens, throw out the needle, re-cap the pen and return the pen to its storage location. Used pens and needles go in a sharps container, not loose in the garbage. You can use a household item, like a coffee can or plastic bottle, for your sharps container, says Tietz. Just make sure it has a secure lid.

One more thing … 

If a small amount of medication leaks out onto your skin, do not take a second dose. Patients sometimes get nervous that they didn’t inject correctly, Tietz says. “But, as long as you hear the two clicks and the visual indicators do what they’re supposed to do, then you can feel confident the injection worked.”

Tietz suggests finding a quiet place to administer injections, whenever possible, to ensure that you’ll be able to hear the clicks.

If you finish your injection and believe something is wrong with the pen, don’t throw it out. You can call the drug manufacturer using the number on the medication box, Tietz says. Pen defects are rare, but they happen. You’ll go through a series of questions with a representative. If they determine that the pen isn’t working, they’ll either send a replacement to your pharmacy or call the pharmacy and have them work with you to get another supply.

Calling your pharmacy first won’t save you any time, Tietz says, because they’ll probably just tell you to call the manufacturer.

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