Vitamin C : skin food
Vitamin C is a naturally occurring active substance with multiple uses such as photoageing, hyperpigmentation, tissue inflammation and promotion of tissue healing. Humans lack the enzyme required for synthesis of Vit. C; hence, they must acquire it from natural sources such as citrus fruits, green leafy vegetables, strawberries, papaya and broccoli.
The bioavailability of Vit. C in the skin is inadequate when it is administered orally. The use of topical ascorbic acid is therefore favored in the practice of dermatology.
BENEFITS OF VITAMIN C IN SKIN
1.- Antioxidant action:
Vit. C, is one of the most plentiful antioxidants that co-exist to protect the skin from reactive oxygen species. Vit. C protects the skin from oxidative stress by sequentially donating electrons to neutralize the free radicals.
2.- Collagen synthesis:
Vit. C stimulates collagen synthesis increasing collagen production in young as well as aged human skin as well as stimulating qualitative changes in the collagen molecule.
Vit. C decreases the melanin formation. However, Vit. C is an unstable compound. It is therefore often combined with other depigmenting agents such as liquorice for better depigmenting effect.
Vit. C has a potential anti-inflammatory activity and can be used in conditions like acne vulgaris and rosacea. It can promote wound healing and prevent post-inflammatory hyperpigmentation.
TOPICAL FORMULATIONS OF VITAMIN C
From a clinical point of view, it is important to note that the efficacy of the Vit. C serum is proportional to the concentration, but only up to 20%. A persistent reservoir of Vit. C is important for adequate photoprotection, and can be achieved by regular 8-hourly applications.
Some froms of vitamin C in the market are not delivered into the dermis in an adequate quantity, while others do not chemically convert to the biologically active form of Vit. C in the skin.
Magnesium ascorbyl phosphate (MAP) is the most stable and preferred ascorbyl ester. It is easily absorbed into the skin. MAP has a hydrating effect on the skin and decreases transepidermal water loss. It is also a free radical scavenger that is photoprotective and increases collagen production under laboratory test conditions. Other useful stable esterified derivatives are: ascorbyl 6 palmitate, disodium isostearyl 2-0 L-ascorbyl phosphate , ascorbic acid sulfate, and tetraisopalmitoyl ascorbic acid.
Topical Vit. C is largely safe to use on a daily basis for long durations. It can safely be used in conjunction with other common topical anti-ageing agents such as sunscreens, tretinoin, other antioxidants and alfa hydroxy acids such as glycolic acid. Care must be taken while applying Vit. C around the eyes.
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