Bioderma Pigmentbio C-Concentrate is a brightening pigmentation corrector serum that combines highly concentrated AHA/BHAs with pure Vitamin C to reduce dark spots and restore skin radiance. This dermatologist-inspired treatment features a light, fluid formula suitable for sensitive skin. The serum contains fresh Vitamin C kept active through a special bottle design and antioxidant Vitamin E to protect against premature aging signs. For use, apply 5 drops each evening to cleansed face and neck for one month. Can be used alone or before Pigmentbio Overnight Renewer. Initial activation requires firmly pressing down the reservoir to release Vitamin C powder, then shaking for 10 seconds after attaching the pipette. Avoid eye area. Some tingling sensation is normal but should quickly subside. Discontinue if irritation persists.