Modalert 200 does not appear to directly impair immunity. Primarily used to treat narcolepsy, sleep apnea, and shift work problem, modafinil promotes alertness. It improves alertness by altering certain brain chemicals, although most users' immune systems are not greatly impacted. Rare adverse effects, such as skin rashes or allergic responses, might point to immune-related problems, though. Off-label or long-term usage should be closely watched by a physician. Before using Modalert on a daily basis, it's crucial to address any concerns with a healthcare professional because, like any medicine, individual reactions might differ.