Naltrexone is a medication usually used for addiction treatment, but in low doses (called Low-Dose Naltrexone, or LDN) it has been explored for conditions with chronic pain and fatigue. For Long COVID, some doctors prescribe LDN to help reduce inflammation in the nervous system and improve symptoms like fatigue, brain fog, and pain. Early studies and patient reports suggest it may be helpful, but strong clinical trial evidence is still limited. Side effects are usually mild, such as vivid dreams, headaches, or stomach upset, and it is generally well tolerated at low doses. At this stage, naltrexone is considered an experimental option that may support symptom relief in some patients.