If you’re living with psoriasis or psoriatic arthritis, you’re probably used to some amount of trial and error to find what works. Certain treatments are really effective for some people—but not so much for others. If topical treatments like steroid ointments or vitamin E analogues don’t work, your doctor may suggest biologics (short for biological medicines). Here’s what you need to know about this relatively new psoriatic treatment if you’re considering it.

First of All, What Are Biologics?

By definition, biologic drugs are made from living cells, rather than being chemically synthesized or pharmacological like some other medications, such as aspirin (Bayer), ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). Biologics bind to chemical messengers that cause inflammation, says board-certified dermatologist Todd Minars, M.D., of Minars Dermatology in Hollywood, Florida. Unlike some psoriasis drugs that work on your whole immune system, biologics only work on the parts that cause the overgrowth of skin cells.

“Biologics help patients with a variety of inflammatory skin diseases. The one they help the most is psoriasis, which is great, as it tends to be a problematic condition for many patients,” Minars says. “They specifically work by targeting and down-regulating some of the inflammatory pathways that seem to be ‘overactive’ in psoriasis patients.”