Yes, Skyrizi (risankizumab) is a biologic medication. Specifically, it is a humanized monoclonal antibody, which means it was engineered from living cells to mimic proteins naturally produced by the immune system. This places it in a fundamentally different category from conventional pills and tablets, which are chemically synthesized in a lab.
What Makes Skyrizi a Biologic
The core distinction between biologics and traditional drugs comes down to how they’re made. Most medications on the market are small molecule compounds manufactured through chemical synthesis. Biologics like Skyrizi are extracted and grown from living organisms, making them far larger and more structurally complex.
Skyrizi is classified as a humanized immunoglobulin G1 (IgG1) monoclonal antibody. In practical terms, that means it’s a lab-made protein designed to behave like an immune system antibody. Instead of broadly suppressing the immune system the way older treatments do, it locks onto one very specific target: a protein called interleukin-23 (IL-23) that drives inflammation in conditions like psoriasis and Crohn’s disease.
How Skyrizi Works in the Body
IL-23 is a signaling protein your immune system uses to trigger inflammatory responses. In autoimmune conditions, this signaling goes into overdrive, causing the immune system to attack healthy tissue. Skyrizi binds to a specific part of IL-23 called the p19 subunit, which prevents IL-23 from connecting with its receptor on immune cells. That interruption dials down the inflammatory chain reaction at its source.
One important detail: IL-23 shares a structural component with another immune protein called IL-12. Older biologics that targeted this shared component blocked both proteins. Skyrizi only binds to the part unique to IL-23, leaving IL-12 untouched. This selective approach is thought to preserve more normal immune function while still controlling the disease.
Because it’s a large protein, Skyrizi can’t be taken as a pill (your digestive system would break it down). It has to be injected, either subcutaneously (under the skin) or, for the initial phase of certain conditions, intravenously. Once in the bloodstream, it has a long half-life of roughly 28 days, meaning it clears from your system slowly. That’s why maintenance injections can be spaced weeks apart rather than taken daily.
What Skyrizi Is Approved to Treat
The FDA has approved Skyrizi for four conditions:
- Moderate to severe plaque psoriasis
- Psoriatic arthritis
- Crohn’s disease
- Ulcerative colitis
For psoriasis and psoriatic arthritis, the maintenance schedule is one injection every 12 weeks after initial loading doses at weeks 0 and 4. For Crohn’s disease and ulcerative colitis, maintenance injections come every 8 weeks. The longer gaps between doses are a practical advantage that many patients appreciate compared to treatments requiring weekly or biweekly injections.
How Well It Works for Psoriasis
A three-year real-world study tracking psoriasis patients on Skyrizi found that results improved steadily over time. At 16 weeks, about 54% of patients had achieved 90% skin clearance. By one year, that number climbed to roughly 81%, and by three years it reached 99%. Complete skin clearance (100% improvement) followed a similar upward trend: about 35% at 16 weeks, 66% at one year, and 75% by year three.
These numbers are notable because they come from real-world clinical practice, not the controlled conditions of a clinical trial, which suggests the benefits hold up in everyday use.
Side Effects and Safety Screening
Across 17 clinical trials, the most commonly reported side effects were upper respiratory infections (including common colds), joint pain, headache, and elevated blood pressure. For patients using it for inflammatory bowel conditions, nausea, abdominal pain, and diarrhea also appeared, though these overlap with symptoms of the underlying disease itself.
Because Skyrizi modifies immune function, you’ll need a tuberculosis screening test before starting treatment. This can be a skin test, a blood test, or a chest X-ray, and it needs to happen within six months of your first dose. If you have risk factors for TB, your doctor will repeat this test annually. If the screening comes back positive, further testing is required to rule out active infection before treatment can begin. Latent TB must be treated first.
How You Take It
For psoriasis and psoriatic arthritis, Skyrizi is given as a subcutaneous injection, which you or a caregiver can do at home using a prefilled syringe or pen. Each dose is 150 mg. The startup schedule involves injections at week 0 and week 4, then once every 12 weeks after that.
For Crohn’s disease and ulcerative colitis, treatment starts with intravenous infusions given at a clinic during an induction phase. After that, you transition to subcutaneous injections at home every 8 weeks. An on-body injector is also available for these conditions, which is a device you attach to your skin that delivers the dose over a few minutes without needing to hold a syringe.
Biologics vs. Traditional Medications
If you’re comparing Skyrizi to pills you might have taken for the same condition, the differences go beyond how it’s delivered. Traditional small molecule drugs spread throughout the body and often affect multiple systems, which is why they tend to carry a wider range of side effects. Biologics are precision tools: they target one specific molecule in your immune system and leave everything else largely alone.
The tradeoff is complexity. Biologics are expensive to produce because they require living cell cultures rather than chemical reactions. They need careful temperature-controlled storage (Skyrizi must be refrigerated). And they can’t survive the digestive tract, so injection or infusion is the only option. For many patients with moderate to severe autoimmune conditions, though, the targeted approach and less frequent dosing make biologics a significant step up from older therapies.