Vitamin C is one of the most common ingredients in skin care, acclaimed for its ability to protect skin from environmental stressors, diminish dark spots, brighten complexion and reduce signs of aging. The naturally occurring antioxidant is often used to treat hyperpigmentation and skin laxity and promote overall skin health.
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Vitamin C is one of the most common ingredients in skin care, acclaimed for its ability to protect skin from environmental stressors, diminish dark spots, brighten complexion and reduce signs of aging. The naturally occurring antioxidant is often used to treat hyperpigmentation and skin laxity and promote overall skin health.
“If we were to sum up the three main properties of vitamin C, they would be: potent antioxidant to help improve skin health; skin brightener to effectively treat hyperpigmentation; and collagen producer to improve skin firmness,” said Alisar Zaher, Ph.D., senior director of research and clinical development at Revision Skincare.
Vitamin C protects the skin from oxidative stress by sequentially donating electrons to neutralize free radicals. The exposure of skin to UV light generates free radicals that have the potential to start chain or cascade reactions that damage the cells. Oxidative stress can trigger cellular events that lead to collagen breakdown, inflammation and skin aging.1
According to Dr. Zaher, patients are recommended to incorporate vitamin C as part of their “A, B and C” of skin care. The “A” represents vitamin A, “B” is the broad-spectrum protection with a sunscreen and “C” represents vitamin C or L-ascorbic acid, which is the purest form of vitamin C.
Vitamin C can be combined with sunscreen or retinol to improve anti-aging benefits, as well as other common skin care ingredients like hydroquinone, niacinamide, kojic acid and tranexamic acid. The ingredients all have different pathways, and some may not be proper for all patients, depending on the concentration and season of use, according to Zaher.
“What is truly unique about vitamin C is that more is more,” Zaher said. “This vitamin itself has many unique pathways within the skin that leads to skin health.”
Ascorbic acid can be unstable and difficult to use in formulations. It can easily degrade in water, as well as when exposed to oxygen and metal ions. Zaher suggests maintaining the stability by incorporating ingredients that remain stable in low PH formulations, like ferulic acid and vitamin E.
“This degradation process is accompanied by a color change in the product, which turns yellowish to brown over time,” Dr. Zaher said. “To mitigate the stability challenges faced with ascorbic acid, modifications to the chemical structure include binding ionic salts to the molecule to produce sodium ascorbyl phosphate or magnesium ascorbyl phosphate. Another strategy utilizes lipophilic derivatives to produce ascorbyl 6-palmitate and tetrahexyldecyl ascorbate.”
Zaher also recommends the Duke Antioxidant patent, which outlines the formulation parameters required for effective delivery of vitamin C into skin, and encapsulation into delivery systems like liposomes.
Although L-ascorbic acid has traditionally been the standard for vitamin C, Zaher suggests that the tide has shifted to a preference of tetrahexyldecyl (THD) ascorbate.
“This molecule is a lipid-loving version of vitamin C containing long chains of hexyldecanoyl; think of long chains of vegetable lipids which have significant emollient properties,” Zaher said. “THD ascorbate is formulated at skin neutral pH and is super easy to formulate with. Formulating with the THD ascorbate allows one to produce serums, lotions and thicker creams.”
REFERENCE:
- Telang PS. Vitamin C in dermatology. Indian Dermatol Online J. 2013 Apr;4(2):143-6. doi: 10.4103/2229-5178.110593. PMID: 23741676; PMCID: PMC3673383.
