Vitamin C Serum

Key compounds: Ascorbic Acid, Ferulic Acid, Magnesium Ascorbyl Phosphate

How to take: Apply once daily in the morning to clean, dry skin before other serums, moisturizers, and sunscreen to leverage its antioxidant protection against environmental stressors.

Absorption: Topical L-ascorbic acid requires a low pH (typically 3.0-3.5) to be un-ionized and penetrate the stratum corneum effectively. Derivatives like Sodium Ascorbyl Phosphate are more stable but require enzymatic conversion in the skin to active L-ascorbic acid.

Stacks well with: Vitamin C serum is synergistically amplified when combined with Vitamin E and Ferulic Acid, which stabilize L-ascorbic acid and enhance its photoprotective capabilities against oxidative stress. Daily application of a broad-spectrum sunscreen is crucial to complement its protective benefits.

Evidence tier: moderate