Definition: L-Ascorbic Acid is the Chirally Correct form of Vitamin C and the most effective for the skin. Stimulates collagen production.
Topical vitamin C must be in the form of L-ascorbic acid to be useful to the body and skin. L-ascobic acid is unstable and tends to break down rapidly, that's why it is so difficult to produce for cosmetic preparations. Once it is in the skin, studies show that L-ascorbic acid stimulates collagen synthesis, provides photoprotection, stays in the skin or up to 72 hours, and prevents UV immunosuppression, a reaction that occurs in more than 90% of skin cancer patients.
Vitamin C and Sun Protection: Topical vitamin C protects skin against harm caused by exposure to sunlight. It does this by neutralizing reactive oxygen species (free radicals), the highly reactive molecules produced by the interaction of sunlight, cell membranes, and other components of skin tissue. It does not absorb light, and hence, is not a sunscreen, so it should not be used in replacement of sunscreen, but rather is a good companion to sunscreen products. Plus, once vitamin C gets into the skin, it cannot be washed, rubbed, or perspired off.
Vitamin C is what is known as an antioxidant. Antioxidants protect skin by neutralizing free radicals, which would otherwise destroy skin and its components. These free radicals are stimulated by ultraviolet light and also occur naturally in the oxygen atmosphere.
Vitamin C and Collagen: Vitamin C is the only antioxidant that has been proven to increase collagen synthesis. Collagen synthesis is essential to maintain healthy skin. Studies show that collagen decreases with aging and that photoaging accelerates the decrease. L-ascorbic acid serves as a signal, relaying a critical message to collagen genes to synthesize collagen, as well as being a cofactor for two enzymes important in collagen synthesis.
Ineffective Vitamin C Preparations: Wanting to offer vitamin C products, many companies have used derivatives of vitamin C, such as ascorbyl palmitate and magnesium ascorbyl phosphate. Derivatives are easier to stabilize, but they are not L-ascorbic acid, which is the only form of vitamin C the body can use.
Recent studies indicate that vitamin C derivatives do not perform the same way as topical L-ascorbic acid. These studies show that derivatives are either not absorbed or not converted to L-ascorbic acid in high enough concentrations to have an effect.
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