Key takeaways:
Tremfya (guselkumab) is an injectable medication that treats psoriasis and psoriatic arthritis in adults and kids ages 6 years and older. After your first dose, you can conveniently inject it at home.
Remember to wash your hands and clean your injection site before you administer Tremfya. And make sure to place the used injection device into a sharps container after you inject your dose.
There are ways to save on Tremfya. A manufacturer savings card can help you access Tremfya for as little as $0 per dose, if you're eligible. A patient assistance program is also available.
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Tremfya (guselkumab) is an injectable medication that treats psoriasis and psoriatic arthritis in adults and kids ages 6 years and older. You’ll likely receive your first dose from a healthcare professional as an injection under the skin. This supervision helps make sure you’re comfortable with the injection process. If everything is good to go after that, you can conveniently inject Tremfya yourself at home.
Even so, learning to administer the shot on your own may seem intimidating. But don't worry — we'll walk you through a few pharmacist-backed tips for mastering your Tremfya injections.
Keep in mind: Tremfya is also FDA approved to treat ulcerative colitis and Crohn's disease in adults. For these conditions, your first doses may be given either as an IV infusion at a hospital or clinic or as an injection under the skin. After that, you’ll give yourself maintenance doses under the skin.
1. Where to inject Tremfya
You can inject Tremfya into your stomach or the front of your thighs. If you don't want to inject it yourself, someone else can inject it in the back of your upper arms. The site you choose depends on personal preference, but the front of the thigh is recommended in many cases.
However, if you're injecting the medication into your stomach, make sure it's at least 2 inches away from your belly button. You'll also want to avoid injecting into patches of skin affected by psoriasis or appearing red or tender.
Good to know: It's best to change the location of your injection each time you inject Tremfya. This helps lessen the chance of injection site reactions and irritation.
2. How to inject Tremfya (in 4 steps)
Tremfya is injected under the skin (subcutaneously). It comes in three forms: a patient-controlled injector (called the One-Press injector), a prefilled syringe, and a prefilled pen. All three forms contain a single dose and should only be used once.
Between them, some people prefer to use the One-Press injector. The needle is hidden, and you can determine the speed of the injection. Depending on what you’re comfortable with, you can inject it faster or slower. It doesn’t require fine motor skills to use, either. Others may prefer the prefilled pen, which has an audible click when the injection starts and another when it’s complete.
Step 1: Getting started
Remove your Tremfya device from the refrigerator and let it come to room temperature (up to 86℉). This should take about 30 minutes and helps lessen injection pain.
Find a clean workplace and collect your injection supplies. This includes an alcohol swab, cotton ball or gauze pad, bandage, and a sharps container.
You'll then need to inspect your medication. First, check the expiration date on the Tremfya carton to make sure it hasn't passed. Then, check to make sure the seal on the carton isn't broken and look for any cracks in the device. You'll also want to make sure the liquid inside your device is clear or slightly yellow. Don't inject your dose if the device is broken or if the medication is expired, cloudy, or has large particles in it.
Finally, clean your hands with soap and water or hand sanitizer. Then, clean the injection site with an alcohol swab using a circular motion and allow it to air dry.
Step 2: Preparing your dose
The Tremfya injection process differs based on which device you're using. But removing the cap comes first.
One-Press injector: Pull off the clear cap on the end of the One-Press injector and throw it away. This will expose the gray needle guard.
Prefilled syringe: Hold the middle of the syringe in one hand and pull the needle cover straight off with the other. You can throw this away. Don't worry if there's a drop of liquid at the tip of the needle — this is normal.
Prefilled pen: Pull the cap straight off — you’ll see the yellow or teal safety guard underneath, depending on your dose. You can throw this away.
For any device, you have 5 minutes to inject your dose after removing the needle cover.
Step 3: Injecting your dose
After you’ve decided where to inject your dose, here are some general tips to follow to make sure that you inject it the correct way.
One-Press injector
Place the injector at a 90-degree angle (straight up and down) on the intended injection site. Then, firmly push the handle all the way down until you can't see the teal body of the injector. You may hear a click once the injection begins or feel resistance. This is normal.
Once the injection is completed (you can’t push down anymore, and the teal body of the injector is no longer visible), you may hear another click. Remove the injector from your body.
Keep in mind: The medication is injected as you push. It’s a little different from auto-injectors that time the dose for you. Push at a speed that's comfortable for you. But make sure not to prematurely lift up after you start the injection process; you may not get the full dose.
Prefilled syringe
Pinch an area of cleaned skin with your free hand. Then, insert the needle at a 45-degree (slanted) angle using a quick, dart-like motion. After the needle is in, let go of the pinched skin and use your free hand to hold the middle of the syringe. Slowly press down on the plunger with your opposite hand until it stops.
Once the injection is completed, let go of the plunger. This will remove the needle from your skin, and the safety guard will cover the needle.
Prefilled pen
Place the pen flat against your skin at a 90-degree angle and press down against your skin to start the injection. You’ll hear one click when the injection starts and another when it finishes. Keep the pen in place until you hear the second click and the yellow indicator has stopped moving. This process should take about 10 seconds.
Step 4: Clean-up
Place the used injection device into your sharps container. Each device only contains one dose, so no need to save it for later.
A small amount of bleeding is normal, too. If this happens, apply pressure to the injection site with a cotton ball or gauze pad for 10 seconds. Don't rub the injection site. Apply a bandage if needed.
3. Storing Tremfya properly can help it work at its best
It’s important to store your unused Tremfya devices in their original container. This helps protect the medication against light and physical damage.
You should also keep Tremfya in the refrigerator (36℉ to 46℉) until about 30 minutes before your dose. Unlike other injectable medications, Tremfya can't be kept at room temperature for too long. Once you remove it from the refrigerator, you should inject it within 4 hours. You shouldn’t keep it at room temperature for longer than that.
To be cautious, it’s helpful to set an alarm for yourself when you remove Tremfya from the refrigerator so you don't accidentally leave it out longer than recommended. Also avoid storing it on the top shelf where it could freeze. If Tremfya freezes, you shouldn't use it — even after it thaws. Avoid storing it in the refrigerator door too; this location is more prone to temperature changes.
4. Set reminders for your injection days
You'll likely only inject Tremfya once every 2 months (8 weeks). In some cases, you may administer it every month.
Since this is relatively infrequent, it can be hard to remember when you administered your last dose. Calendar alerts and medication reminder apps can help you remember when your next dose is due.
If you miss your dose of Tremfya, inject it as soon as you remember and continue your regular dosing schedule. Check with your healthcare professional if you're unsure about when you should inject your next dose.
5. Keep an eye out for these Tremfya side effects
Like all medications, Tremfya can cause side effects. Many common side effects can be managed at home and should go away once your body gets used to the medication. But other side effects can be more serious and should be discussed with a healthcare professional without delay.
The most common Tremfya side effects include:
Upper respiratory infections (sore throat or the common cold)
Headache
Mild injection site reactions (redness, swelling, or itching)
Joint pain
Serious side effects
Although rare, some Tremfya side effects are more serious and should be reported to your healthcare team immediately. Stop using Tremfya and seek emergency medical care right away if you experience swelling of your face or mouth or have trouble breathing after an injection. These are symptoms of a potentially serious allergic reaction.
What’s more, because of its effects on the immune system, Tremfya increases the risk of severe infections, including tuberculosis. Before you start Tremfya, tell your prescriber if you've been exposed to tuberculosis in the past or have any current symptoms of an infection.
How to save on Tremfya
There are ways to save on Tremfya, which is only available as a reference (brand-name) medication. GoodRx can help you navigate between copay savings cards and patient assistance programs to save money on your prescription.
Save with a copay savings card. If you have commercial insurance, you may be eligible to pay as little as $0 for Tremfya using a savings card from the manufacturer.
Save with patient assistance programs. If you’re uninsured or underinsured, you may be eligible for Tremfya’s patient assistance program, which offers the medication free of charge.
The bottom line
Tremfya (guselkumab) is given as an injection under the skin into your stomach, thighs, or arms. You can give yourself the injection at home once you've been trained to do so. But be sure to change where you inject Tremfya with each dose. And follow the injection steps for your dosage carefully. Tremfya should be kept in the refrigerator until you're ready to give your dose.
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References
Brooks, A., et al. (2025). FDA approves guselkumab (Tremfya) for pediatric plaque psoriasis, psoriatic arthritis. HCP Live.
Janssen Biotech. (2025). Instructions for use: Tremfya prefilled syringe.
Janssen Biotech. (2025). TREMFYA- guselkumab injection [package insert]. DailyMed.
Janssen Science. (2025). Tremfya - storage and stability.
Johnson & Johnson. (2024). TREMFYA® (guselkumab) receives U.S. FDA approval for adults with moderately to severely active ulcerative colitis, strengthening Johnson & Johnson’s leadership in inflammatory bowel disease.
Johnson & Johnson. (2025). U.S. FDA approves TREMFYA® (guselkumab), the first and only IL-23 inhibitor offering both subcutaneous and intravenous induction options, for adult patients with moderately to severely active Crohn’s disease.
MedlinePlus. (2025). Guselkumab injection.
