Kiehl's Powerful-Strength Line-Reducing Vitamin C Serum is the brand's highest-concentration Vitamin C formula — delivering 10.5% pure Vitamin C (L-Ascorbic Acid) in a stable, high-efficacy concentrate that visibly reduces fine lines, improves radiance, evens skin tone, and supports collagen synthesis with consistent daily use. Clinically proven to reduce the appearance of lines and wrinkles while dramatically improving skin brightness.

L-Ascorbic Acid (10.5%) is the most bioavailable and clinically researched form of Vitamin C — the gold standard for topical antioxidant and brightening activity. At 10.5%, this formula provides the threshold concentration where L-Ascorbic Acid begins producing the most clinically significant improvements in collagen synthesis, free radical neutralization, and tyrosinase inhibition for brightening. Hyaluronic Acid provides simultaneous hydration to prevent the dryness that can accompany high-concentration Vitamin C serums. Vitamin E (Tocopherol) acts synergistically with Vitamin C, extending and amplifying its antioxidant effect. The fragrance-free, paraben-free formula is clinically tested for all skin tones and types.

Apply in the morning after cleansing, before moisturizer and SPF. Use consistently for a minimum of 4 weeks for visible results. Available at Beauty Riche — authorized Kiehl's retailer with same-day shipping.

Kiehl's Powerful-Strength Line-Reducing Vitamin C Serum 1.7oz – 10.5% Vitamin C Concentrate