What percentage of niacinamide is effective?

Niacinamide has been shown to be effective starting at 2%, with most research using 4–5% concentrations for sebum control and hyperpigmentation. Concentrations of 10% are used in some products for more pronounced results. Going above 10% does not offer additional benefits and may cause flushing or irritation in some individuals. A 5% concentration offers an excellent balance of efficacy and tolerability for most people.