Supplements That Cause Flushing

Niacin (Vitamin B3)

• Niacin supplementation can cause flushing, which typically occurs in the face, arms, and chest within 30 minutes of ingestion and can last for about 60 minutes, according to Clinical Nutrition 1
• Flushing is the most common side effect of niacin supplementation, which can occur at doses as low as 30 mg, as reported by Clinical Nutrition 1

Serious Adverse Effects of Niacin

• Niacin can cause hepatotoxicity ranging from mild liver enzyme elevation to acute liver failure, typically at doses around 3 g per day, as stated in Clinical Nutrition 1

Clinical Considerations

• The tolerable upper intake level for niacin is 35 mg/day niacin equivalents, with flushing listed as the adverse effect upon which this upper limit is based, according to Diabetes Care 3
• Nicotinamide mononucleotide (NMN), a precursor to NAD+, does not typically cause flushing unlike nicotinic acid (another form of niacin), as noted in Praxis Medical Insights 2