Although side effects may vary depending on the specific NR Booster used, they are generally mild and temporary. Common side effects include headaches, fatigue, gastrointestinal upset, and skin irritation, which usually subside within a few days of starting supplementation. In rare cases, lower quality products can cause more serious side effects such as liver damage and allergic reactions. It is important to note that such serious side effects are typically associated with products that do not use clinically proven ingredients.