What is Vitamin C?
Vitamin C is a naturally occurring antioxidant. It is vital for normal cell growth and collagen synthesis, which in turn improves the skin’s appearance, especially as we age. Since humans lack the enzyme required to produce vitamin C, we must obtain it from our diet. Citrus fruits, berries, broccoli and other dark green leafy vegetables are good sources of Vitamin C.
The chemically active form of Vitamin C is L-ascorbic acid. L-ascorbic acid (LAA) and D-ascorbic acid are both found in nature however only LAA is biologically active therefore it is useful in medical practice.
In dermatology, topical use of vitamin C is preferred as the bioavailability (the amount the body can effectively use) is insufficient when administered orally. This is due to a limited amount of the vitamin being absorbed by the body despite high oral dosage. As such, Vitamin C creams, serums and transdermal patches are preferred for the benefit of skin.
Shoppers tip: Always ensure the products are packaged to protect them from ultraviolet light and air as ascorbic acid is unstable and its effectiveness will gradually become diminished if exposed to these elements. Look for airtight, opaque, pump action packaging. If the product you are buying is dark yellow or brown it has oxidised and will not be effective and may in fact do more harm than good.
What does it do?
Skin is the main obstacle for efficient absorption of vitamin C from topical sources. Therefore, to ensure delivery, penetration and biologic activity of the vitamin into skin, formulation characteristics are vital to enhance the skin’s natural antioxidant activity. Absorption of vitamin C by skin is said to depend on pH and agents with a pH below 4 help ascorbic acid infiltrate into skin.
- Promotes collagen production and helps make it stable and stronger. It also extends its life by protecting against the enzymes that break it down.
- Acts as a depigmenting agent by decreasing the melanin formation.
- Reduces damage caused by ‘free radicals’. When our body produces energy at cellular level, it generates free radicals (oxygen molecule loses an electron) as a by-product of oxygen metabolism. The formation of these free radicals is increased by external factors such as sunlight (UVA and UVB), radiation, pollution, emotional stress or infection to name a few. To re-balance, free radicals may take electrons from normal, healthy cells leading to a cascade of cell damage which results in skin ageing. However, antioxidants like Vitamin C can donate an electron, reducing the number of free radicals and helping to protect the skin and reduce visible signs of ageing.
Topical Vitamin C is effective in treating skin conditions such as acne vulgaris and rosacea. It can help improve pigmentation disorders, rejuvenate photo-damaged skin by reducing fine lines and wrinkles, and protect skin against damage caused by sunlight.
Mild burning, stinging, erythema (redness) and dryness may be observed after use of topical vitamin C. These can easily be treated using a moisturiser. If any of these effects persist or worsen, it is important to speak with a doctor or other health professional promptly.
Interactions with other medicines:
Topical vitamin C can be used safely in conjunction with other common topical anti-ageing agents such as sunscreens, tretinoin, other antioxidants and alphahydroxy acids such as glycolic acid.
Minor adverse reactions include a yellowish discoloration of the skin due to oxidative changes of vitamin C.
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Telang, Pumori Saokar. “Vitamin C in Dermatology.” Indian Dermatology OnlineJournal 4.2 (2013): 143–146.
PMC.Farris PK. Cosmetical Vitamins: Vitamin C. In: Draelos ZD, Dover JS, Alam M, editors.Cosmeceuticals. Procedures in Cosmetic Dermatology.2nd ed. New York: Saunders Elsevier; 2009. pp. 51–6.