What percentage of niacinamide is best in a serum?

Most popular formulas land at 10%, which verified-purchase reviewers across this pool gravitate toward for brightening and pore appearance. Higher concentrations like 20% exist for stronger discoloration treatment, while 5% emulsions are positioned for sensitive skin or body use. Many dermatology-minded users find diminishing returns and a higher chance of irritation above 10%, so beginners often start lower.