Both are birth control patches. Twirla is a 28 cm2 circular patch with levonorgestrel and Xulane, a generic brand of Ortho Evra, is a 14 cm2 square-like patch with norelgestromin. Zafemy is another generic of Ortho Evra and is a 12.5 cm2 square-like patch. Also, Xulane and Zafemy have a higher delivered estrogen dose (50mcg) than Twirla (30mcg). The higher dose puts you at higher risk of blood clots, stroke, death. However, the higher dose might be appropriate for those on medications that “eat up the estrogen.” Check with your doctor on what’s best for you.