While NAD+ boosters are generally recognized as safe for most adults, potential downsides include financial cost, as high-grade supplements and intravenous therapies can be quite expensive over time. Minor physiological side effects can occur, such as transient gastrointestinal discomfort, nausea, headaches, or flushing sensations. Furthermore, because NAD+ plays a fundamental role in cellular growth and metabolism, individuals with active cancer or specific medical conditions are often advised by physicians to exercise caution and avoid excessive cellular boosters.