Oral Vitamin C

Abstract Vitamin C (ascorbic acid) is an essential, water-soluble micronutrient with central relevance to “beauty-from-within” strategies. As a required cofactor for prolyl and lysyl hydroxylases, vitamin C enables stable collagen I/III and tropo-elastin formation, thereby supporting dermal extracellular matrix (ECM) integrity and wrinkle attenuation. Concurrently, it delivers potent antioxidant defense against UV-/pollution-derived reactive oxygen species (ROS), limiting oxidative degradation of collagen and elastin and helping to prevent photoaging. Vitamin C also modulates pigmentation by inhibiting tyrosinase and, when paired with Niacinamide, complements the suppression of melanosome transfer- together improving tone evenness with high tolerability. A daily 200 mg oral dose sits in the functional “sweet spot”: it sustains plasma ascorbate near the threshold for systemic antioxidant activity and collagen biosynthesis, remains well below the 2,000 mg/day UL, and avoids the absorption plateau observed at ≥500 mg/day. Within multi-ingredient nutricosmetic formulations, vitamin C synergizes with Niacinamide (tone/barrier), elastin peptides (elastic-matrix support under oxidative control), hyaluronic acid (hydration and HA preservation), and ceramide NP (barrier lipid replenishment) to deliver integrated outcomes across anti-oxidation, brightening, firming, and barrier repair. Collectively, evidence supports vitamin C as an indispensable systemic cofactor and synergist in oral protocols targeting structural skin aging, oxidative stress, and dyschromia.