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Risankizumab is one of the IL-23 blockers that changed what I tell patients is realistic — a lot of people get to skin that looks essentially clear. After the first two doses it is one injection every twelve weeks, easy to live with and easy to forget, so put the dates in your phone. It is not better or worse than the other biologics, just a different trade: fewer injections and a narrow target against a shorter safety record. Which one you end up on usually comes down to your joints, your other conditions and your insurance.
— Dr. Schwarz, Board Certified Dermatologist
Key Facts
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| Also called | Skyrizi |
| Drug class | Interleukin-23 (IL-23) inhibitor. A biologic, meaning a protein grown in living cells rather than made by chemistry |
| Taken as | Injection under the skin, from a pen or a prefilled syringe you use at home |
| Typical course | Long term, for as long as it keeps working and is tolerated |
| Time to work | Often noticeable by 4 weeks, judged at about 16 weeks |
| Prescription only | Yes |
What It Is
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Risankizumab is a biologic — a large protein grown in living cells rather than built in a factory. It is injected because stomach acid would destroy it. It is a lab-made antibody that locks onto one inflammation signal, interleukin-23, and takes it out of play. Approved in the United States in 2019 for moderate to severe plaque psoriasis, and later for psoriatic arthritis, Crohn's disease and ulcerative colitis. The bowel doses are much larger and given a different way, so the schedules are not interchangeable. There is no biosimilar version.
How It Works
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Psoriasis runs on a chain of signals, and interleukin-23 sits near the top. It keeps a group of immune cells switched on, and those cells release interleukin-17, which tells skin cells to multiply far faster than normal. That is the thick, red, scaly plaque.
Risankizumab binds a part of interleukin-23 called p19 and blocks it. Because the block is upstream, everything below it quiets down without being blocked individually.
The target is narrow. Interleukin-23 does much less infection-fighting work than a broad signal like TNF, so this class has a lighter side effect profile and no boxed warning. Not zero risk — tuberculosis screening is still done before the first dose. The drug also lingers in the body, which is why doses can be twelve weeks apart.
Here is where Risankizumab (Skyrizi) acts in the skin, and what the others do instead.
About Risankizumab (Skyrizi)
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Skin basics
Risankizumab (Skyrizi) works on the immune signal throughout the body, not just where the rash is. That is what makes it powerful in widespread disease, and why it needs monitoring. Blocks IL-23, the signal sitting upstream of the whole psoriasis cascade. After the first doses it is an injection every three months.
Risankizumab (Skyrizi) arrives from the inside, carried to the skin by the blood, rather than crossing the barrier from outside. That is why it works everywhere at once, and why it needs monitoring.
In a plaque, skin cells travel from the bottom of the epidermis to the surface in four to six days instead of a month, and pile up as scale. This slows them back down, so the plaque thins.
The outer film of dead cells and oil. It holds water in and keeps irritants out, and it is thinner than a sheet of paper. Almost every dry, itchy, stinging skin problem starts here.
The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.
The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.
What It Treats
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Forms
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For psoriasis it comes as a single-dose pen — an autoinjector you press against the skin — and as a prefilled syringe. Same drug either way. Older packs gave the dose as two 75 mg syringes; the single 150 mg pen or syringe has replaced them.
The Crohn's and ulcerative colitis versions are different products, including an intravenous drip to start and a larger on-body injector worn on the skin.
It is kept in the fridge:
Strengths
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The dose is fixed in the device. No measuring, no adjusting by weight.
Dose
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Two starting doses close together, then a long steady interval. Not adjusted for body weight.
How to Take It
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When to take it: Any time of day. The calendar matters more here than with a weekly drug. Twelve weeks is long enough that people lose track, so put every dose date in your phone and book the next reminder the day you inject. Take it out of the fridge 15 to 30 minutes before and let it warm on the counter. Cold liquid stings. No hot water, no microwave. Inject into the front of the thigh or the belly, at least two inches from the navel. The back of the upper arm works if someone else is doing it. Rotate the site, avoid skin that is bruised, tender, hard or scarred, and never inject through a plaque. Ask for training before the first dose. Used devices go in a sharps container.
If you miss a dose: Inject as soon as you remember, then count twelve weeks from that day. If it has been much longer than twelve weeks, call the prescriber first so the schedule can be reset.
What to Expect
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Side Effects
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The IL-23 injections are the best tolerated of the psoriasis biologics. Most people report nothing beyond the occasional cold.
Common — expected, and they settle
- Colds and upper airway infections
- Injection site reaction Redness or soreness for a day or two.
- Headache
- Tiredness after a dose
Tell your doctor — worth a call, not an emergency
- An infection that is not clearing
- A painful rash in a band, or blisters Shingles.
- Rising liver enzymes Uncommon, and checked if you have symptoms.
- Any live vaccine you are offered Ask your doctor first.
Stop and get care
- Fever with shaking chills or feeling very ill
- A cough with fever, night sweats and weight loss: Tuberculosis is screened for before you start.
- Hives, facial swelling or trouble breathing
What to Avoid
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- Live vaccines These contain a weakened live germ — measles-mumps-rubella, chickenpox, yellow fever and the nasal spray flu vaccine. Have any you need before you start. Non-live vaccines, including the flu shot, COVID vaccines and Shingrix, are usually encouraged.
- Injecting during a fever or infection Hold the dose and call the prescriber. On this schedule a dose can wait a week or two.
- Injecting into a plaque or bruise Hard, red or tender skin counts too. It hurts more and absorbs less predictably.
- Letting the device freeze or overheat Sitting in sunlight counts. Replace it rather than use it.
- Letting the schedule drift by months The most common practical problem with this drug — the gap is long enough to forget.
- Reusing a pen or syringe Every device is single use.
Monitoring
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Everyone is screened for tuberculosis before the first dose — a skin test or TB blood test, plus a chest X-ray if that is positive. Dormant TB is treated first. This class probably carries less TB risk than the TNF blockers, but screening is not optional.
Hepatitis B and C are usually checked at the same time.
After that there is no fixed blood test schedule. Risankizumab does not need the regular liver and blood count testing methotrexate does. Monitoring is clinical: the skin, whether infections are more frequent, whether the dose dates are kept. TB testing is repeated yearly or by exposure risk.
There is no boxed warning. The most common side effects reported are upper respiratory infections, headache, tiredness, fungal skin infections and injection site reactions. Serious allergic reactions are rare but are why the first dose is often given with someone trained nearby.
If You Stop
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No taper, no withdrawal reaction. Stopping does not set off the sudden severe flare that stopping oral steroids can. The drug clears slowly, so psoriasis usually comes back slowly too, often several months after what would have been the next dose. A long quiet gap is not proof the psoriasis has gone. Restarting after a break generally works. Antibodies against the drug are reported less often with this class than with the older biologics. If you need to stop for surgery, an infection or a pregnancy plan, plan it in advance so the restart can be timed.
Cost
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The list price runs to tens of thousands of dollars a year. Almost nobody pays that; what you pay depends on your plan. It is brand only — no generic, no biosimilar — so there is no cheaper equivalent to switch to. That is a real difference from adalimumab. Prior authorization is close to universal. Most plans require documented failure of something cheaper first — phototherapy, methotrexate, sometimes another biologic. Denials are usually about missing records rather than the drug, and appeals succeed reasonably often when the history is documented. Manufacturer copay cards can cut the cost to very little with commercial insurance. By law they cannot be used with Medicare or Medicaid. For those plans, or no insurance, the manufacturer's patient assistance program and independent foundations are the usual routes. Terms change often. One practical note: because doses are twelve weeks apart, a change of insurance or a formulary switch in January can land in the middle of a dosing gap. Check coverage before the next dose is due, not the week it is.
Ask Your Doctor
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How It Compares
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Myths
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- "A biologic is chemotherapy." It is not. Chemotherapy attacks fast-dividing cells throughout the body. Risankizumab binds one inflammation signal and leaves the rest of the immune system working.
- "Four injections a year means it is weaker." The interval reflects how long the drug stays in the body, not how strong it is. Levels stay high enough between doses.
- "It wipes out your immune system." It blocks one signal in one pathway. The most common side effects reported are colds and upper respiratory infections. The risk is not zero — hence the tuberculosis screening — but this is not immunosuppression the way chemotherapy does it.
- "You can never have vaccines again." Only live vaccines are avoided. The flu shot, COVID vaccines, pneumonia vaccines and Shingrix are not live and are usually recommended.
- "If my skin is clear I can stop." Clear skin on treatment means it is working, not that the psoriasis has gone. Decide with the prescriber, knowing plaques usually return over the following months.
Questions Patients Ask
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What does biologic mean?
A large protein grown in living cells rather than a chemical made in a factory. That is why it is injected, and why it lives in the fridge.
Really only four injections a year?
After the first two doses, four weeks apart, yes. The drug stays in the body long enough that the gap can be twelve weeks.
Does the injection hurt?
A few seconds of stinging. Letting it warm to room temperature first makes a noticeable difference.
Do I need blood tests while I am on it?
Tuberculosis and hepatitis before you start, and TB testing often repeated yearly. Beyond that, no routine schedule.
What happens if I am late with a dose?
Inject when you remember and count twelve weeks from that day. If you are weeks or months late, call first.
Can I have vaccines?
Yes, apart from live ones. The flu shot, COVID vaccines and Shingrix are not live. Have any live ones before starting.
References
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- Nast A, Smith C, Spuls PI, et al. EuroGuiDerm Guideline on the systemic treatment of Psoriasis vulgaris - Part 1: treatment and monitoring recommendations. Journal of the European Academy of Dermatology and Venereology : JEADV. 2020. — Journal of the European Academy of Dermatology and Venereology : JEADV, 2020
- Sbidian E, Chaimani A, Garcia-Doval I, et al. Systemic pharmacological treatments for chronic plaque psoriasis: a network meta-analysis. The Cochrane database of systematic reviews. 2022. — The Cochrane database of systematic reviews, 2022
- Bai F, Li GG, Liu Q, et al. Short-Term Efficacy and Safety of IL-17, IL-12/23, and IL-23 Inhibitors Brodalumab, Secukinumab, Ixekizumab, Ustekinumab, Guselkumab, Tildrakizumab, and Risankizumab for the Treatment of Moderate to Severe Plaque Psoriasis: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. Journal of immunology research. 2019. — Journal of immunology research, 2019
- Barberio B, Gracie DJ, Black CJ, et al. Efficacy of biological therapies and small molecules in induction and maintenance of remission in luminal Crohn's disease: systematic review and network meta-analysis. Gut. 2023. — Gut, 2023
- Singh S, Loftus EV, Limketkai BN, et al. AGA Living Clinical Practice Guideline on Pharmacological Management of Moderate-to-Severe Ulcerative Colitis. Gastroenterology. 2024. — Gastroenterology, 2024
- Shehab M, Alrashed F, Alsayegh A, et al. Comparative Efficacy of Biologics and Small Molecule in Ulcerative Colitis: A Systematic Review and Network Meta-analysis. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2025. — Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 2025