Ultra Pure High-Potency 5.0% Niacinamide Serum - BenefitsFree of fragrance and colorants, this concentrated serum is minimally formulated for skin absorption and efficacyKey IngredientsNiacinamide, the form of Vitamin B3 used within Kiehl's formulas, is known to help visibly brighten skin. When used in topical skincare formulas, Niacinamide can also help balance skins surface oil.Research Results*Reported by consumers in a 4-week study **Instrumental measurement in a 4-week clinical study ***Expert grading in a 4-week clinical studyAfter 1 Week, 92% Agree Skin Feels Soothed* Instantly Reduces Excess Oil by 58%** Reduced Blemishes in 1 Week*** - Ultra Pure High-Potency 5.0% Niacinamide Serum