Numbuzin No.5+ Glutathione Vitamin Concentrated Serum is a brightening Korean skincare serum designed to improve uneven skin tone, reduce dark spots, and boost overall skin radiance. It contains powerful ingredients such as glutathione, niacinamide (5%), tranexamic acid (4%), and vitamin C derivatives that help fade hyperpigmentation, acne marks, and dullness while protecting the skin from environmental damage.