For sun damage and aged skin, Vitamin C shines

Most people get their daily dose of vitamin C from a glass of orange juice each morning, but that gift from the sunshine state isn't doing anything for the skin. It's the topial vitamin C in creams, lotions and serums that can benefit several common skin concerns including texture, pigmentation and fine lines.

Lately, vitamin C or L-ascorbic acid, has been getting more attention, particularly from skin care companies that have launched several new C-based products in the last few months. Obagi, SkinCeuticals, PCA Skin, Glytone, Lumixyl, Vichy and others include vitamin C in new topicals.

People have understood that vitamin C is important for health since sailors started eating lemons to stave off scurvy. Topical vitamin C is nearly as important for healthy skin. Scottsdalc dermatologist and PCA Skin chief science officer Jennifer Linder, MD, calls vitamin C one of the most important ingredients for skin care. "It's been known for a long time, but it's one of those things that we're just really appreciating how useful it actually is", says Dr. Linder.

"It's one of the most important ingredients for collagen synthesis: says Charleston, SC, dermatologist Todd Schlesinger, MD. As a cofaclor for collagen, it increases collagen production, but on top of that it reduces collagenase, so it slows down the breakdown of collagen. This not onty helps reduce fine lines, but prevents existing lines from worsening.

After collagen synthesis, vitamin C's next most important job is chasing down free radicals as an antioxidant, so it can be an added help for sun-damaged skin.

Vitamin C frequently turns up in products designed for ski lightening. "It reverses the chain reaction that causes pigmentation," explains Dr. Linder. While vitamin C won't reduce pigment that already exists, it does stop more pigmentation, they really work well together," she adds. Dr. Schlesinger recommends vitamin C as a maintenance product for people who have gone through a hydroquinone regimen for hyperpigmentation. He recommends a minimum solution of 10 percent, while Dr. Linder says the ingredient is most effective at 15 or 20 percent.

One of the newer findings with vitamin C is that it may also have a photoprotective effect of 15 percent solution of L-ascorbic acid, 1 percent ditocopherol and 0.5 percent trans ferulic acid. The solution was applied to skin, then exposed to 2 to 10 minimal erythema doses of ultraviolet radiation. The study found the solution very effective, particulerly in reducing thymine dimer mutations, which are associated with skin cancer.¹

For all its benefits, and no one disputes them, C has a problem. It's inherently unstable. A little time out in the air and it starts to convert to an oxidized form that makes it useless, and in fact may make it do the opposite of what we want. The challenge for product makers is to develop more stable forms and more effective delivery methods to make sure it gets to the skin and works. Makers use methods of encapsulation, suspension and esterification to help stabilize the ingredients so that it penetrates the skin before oxidation occurs.

Dr. Schlesinger recently completed a study on a form of vitamin C (Vitivia) which placed the product in single dose silicone capsules. That method ensured that each does was fresh. Other makers use microencapsulations that open when the solution is rubbed on the skin.

While vitamin C can b effective on its own, it also works well with other vitamins such as A and E. in Dr. Schlesinger's study, which was presented as a poster at the 2010 American Academy of Dermatology meeting in Miami, he used a 10 percent solution of ascorbic acid combined with 0.1 percent retinol, and all participants saw improvement in skin tone, texture and pigmentation.

View the the original article in pdf format here.

Grant Clauser is editor. He can be reached at gclauser@advanceweb.com

References
1. Murray JC, Burch JA, streilein RD, Lannacchione MA, Hall RP, Pinnell SR; A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation. J Am Acad Dermatol. 2008 Sep 59(3):418-25.