Niacin is a type of B vitamin used to help the digestive system, liver, and skin (Reference 2). It is important to incorporate as part of a healthy diet, however it is not without side effects (Reference 3). Most of the side effects experienced with niacin overdose affect the gastrointestinal system and skin (References 1 and 2).
The downside
Normal doses of niacin can induce side effects such as facial flushing and itchiness, however, these usually subside after repeated use of niacin (Reference 2). Other dermatologic side effects may include hyperpigmentation and skin rash (Reference 1). Common gastrointestinal side effects include nausea, vomiting, and diarrhea (Reference 1). Continued use of niacin at high doses has been linked to increased possibility of liver disease. (Reference 3). Consult your physician if you experience repeated and prolonged side effects.
Prescription Niacin Overdose
Very high doses of niacin are available by prescription to prevent or improve a variety of conditions such as heart disease and diabetes (Reference 3). However, niacin can be toxic at high doses and