Stelara is not a steroid. It is a biologic medication, a completely different class of drug that works through a distinct mechanism. The confusion is understandable because Stelara treats many of the same conditions that steroids are prescribed for, including psoriasis, Crohn’s disease, and ulcerative colitis. But the two medications differ in how they work, how they’re taken, and what side effects they carry.
What Stelara Actually Is
Stelara (ustekinumab) is a monoclonal antibody, which means it’s a lab-engineered protein designed to target a very specific part of the immune system. It blocks two inflammatory signaling molecules called IL-12 and IL-23 by binding to a protein subunit they share. These molecules normally trigger immune responses that, in autoimmune conditions, become overactive and attack healthy tissue. By intercepting them before they can dock with immune cells, Stelara dials down the specific pathways driving inflammation in conditions like psoriasis and inflammatory bowel disease.
This precision is the key distinction from steroids. Where a steroid broadly suppresses the entire immune system and reduces inflammation across the body, Stelara targets only the IL-12 and IL-23 pathways. Think of it as using a sniper rifle instead of a shotgun.
How Steroids Work Differently
Corticosteroids like prednisone work by dampening the immune system on a wide scale. They reduce swelling, redness, and pain quickly, which makes them useful for acute flares of inflammatory conditions. But that broad suppression comes with significant trade-offs when used long term: weight gain, bone density loss, elevated blood sugar, mood changes, thinning skin, and increased vulnerability to infections.
Because of these risks, steroids are meant to be short-term treatments. Clinical guidelines for inflammatory bowel disease, for example, recommend limiting steroid courses to three months maximum and always pairing them with a longer-term maintenance therapy. Stelara is one of those maintenance therapies. Many patients start on steroids to get a flare under control, then transition to a biologic like Stelara so they can taper off steroids entirely.
Conditions Stelara Treats
The FDA has approved Stelara for several autoimmune conditions:
- Moderate to severe plaque psoriasis in adults and children aged 6 and older who are candidates for systemic therapy or phototherapy
- Active psoriatic arthritis in adults and children aged 6 and older
- Moderately to severely active Crohn’s disease in adults
- Moderately to severely active ulcerative colitis in adults
For Crohn’s disease specifically, Stelara is indicated for patients who haven’t responded to or couldn’t tolerate other treatments, including corticosteroids. In other words, it’s often prescribed precisely because steroids weren’t a good long-term solution.
Side Effects Compared to Steroids
Stelara’s side effect profile looks nothing like a steroid’s. It does not cause the weight gain, moon face, bone thinning, or blood sugar spikes that make long-term steroid use problematic. The most common side effects are relatively mild: upper respiratory symptoms like nasal congestion and sore throat, headache, fatigue, and occasional urinary tract symptoms.
The more serious concern with Stelara is infection risk, since it does suppress part of the immune system. In a long-term safety study of 878 Crohn’s disease patients followed for an average of about three years, serious infections occurred in 1.8% of patients. The most common were gastrointestinal infections (0.8%) and lung infections (0.3%). Only one patient developed an opportunistic bacterial infection, and no cases of tuberculosis were reported. Malignancies were rare, occurring in 0.8% of patients over the study period.
These numbers are considerably lower than the complication rates seen with prolonged steroid use, which is one reason biologics like Stelara have become preferred for long-term management of autoimmune conditions.
How Stelara Is Taken
Unlike steroids, which are typically taken as daily pills, Stelara is given by injection. For skin conditions like psoriasis, it’s administered as a subcutaneous injection (under the skin) that many patients learn to give themselves at home. For Crohn’s disease and ulcerative colitis, the first dose is given intravenously in a clinic, followed by subcutaneous injections for ongoing maintenance.
The dosing schedule is also far less frequent than daily steroid pills. After the initial doses, maintenance injections are typically given every 8 to 12 weeks. This infrequent dosing is one of the practical advantages patients notice compared to other treatments.
Transitioning from Steroids to Stelara
If you’re currently on steroids and your doctor is starting you on Stelara, you won’t stop steroids abruptly. Steroids need to be tapered gradually because your body’s natural cortisol production slows down during steroid use, and stopping suddenly can cause withdrawal symptoms. Your doctor will typically reduce your steroid dose in steps over weeks while Stelara builds up in your system.
The goal of this transition is steroid-free remission, meaning your condition stays controlled without needing steroids at all. This is considered a key treatment milestone in inflammatory bowel disease because it means you’re avoiding the long-term damage steroids can cause while still keeping inflammation in check. Stelara, as a biologic, is designed to maintain that remission over months and years in a way steroids simply cannot do safely.
Biosimilar Availability
As of mid-2025, the FDA has approved a biosimilar version of Stelara called Starjemza. Biosimilars are essentially the biologic equivalent of generic drugs: they contain a highly similar version of the same active protein and undergo rigorous testing to confirm they work the same way. This may offer a lower-cost option for patients who need ustekinumab therapy long term.