In a 2015 study of 60 healthy female subjects, Crisan et al. used high-frequency ultrasound to determine that the use of a topical vitamin C formulation yielded significant increases in collagen synthesis, revealing the solution to be an effective rejuvenation therapy.21
Skin lightening activity
In 2004, Espinal-Perez et al. conducted a double-blind randomized trial of 5% ascorbic acid, compared with 4% hydroquinone (HQ) water–oil emulsion in 16 female patients with melasma, aged 23-43 years (mean 36 years). Of those treated with vitamin C, 62.5% exhibited good or excellent subjectively assessed skin lightening. There was no statistically significant difference in depigmenting activity in the HQ group, of which 68.7% experienced irritation whereas vitamin C was well tolerated.22
In a randomized, double-blind, placebo-controlled study, researchers used iontophoresis to enhance the penetration of vitamin C into the skin and significantly reduce pigmentation, compared with placebo.23
Although ascorbic acid is viewed by many as ineffective as a depigmenting agent alone, particularly in 5%-10% concentrations, when used in combination with other ingredients such as HQ, it is considered effective.24 In the magnesium-L-ascorbyl-2-phosphate esterified form, however, vitamin C is among the most popular prescribed depigmenting agents around the world, especially in countries where HQ and its derivatives are prohibited.25 In a 2009 16-week open-label study by Hwang et al. of 25% L-ascorbic acid and a chemical penetration enhancer for treating melasma in 40 patients, researchers observed significant reductions in pigmentation.26
In a small split-face study early in 2015, Lee et al. showed that the combination of 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet (QS-Nd:YAG) laser and ultrasonic application of vitamin C was more effective than was the laser treatment alone in achieving a cosmetically acceptable treatment for melasma.27
Vitamin C can be used to diminish or prevent post-inflammatory pigment alteration (PIPA) after procedures because it inhibits tyrosinase, lowers inflammation, and quenches free radicals. In a study of 10 patients, the application of topical vitamin C 2 or more weeks after surgery reduced the duration and degree of erythema after skin resurfacing with a carbon dioxide laser.28
The depigmenting effects of vitamin C can lighten the pigmentation associated with stretch marks and its anti-inflammatory activity can contribute to blunting related redness.12
Although orally administered ascorbic acid is readily bioavailable, ascorbic acid in the skin is quickly depleted and oral supplementation alone does not yield optimal skin levels. Therefore, topical use of vitamin C is desirable. In fact, I tell my patients to use it topically in the morning and add a vitamin C supplement to their diet. Numerous formulation considerations (e.g., packaging, exposure to air or light during use, skin sensitivity, and user preference) are involved in the stabilization and effective penetration of ascorbic acid into the skin, and the process of developing, manufacturing, and packaging of effective, stable vitamin C products is expensive.
Vitamin C, particularly when combined with other ingredients, has been shown to be an integral constituent in topical antioxidant, antiaging, and depigmenting formulations that show promise in the dermatologic armamentarium. It is a great choice for use in a prep-procedure skin care regimen to speed healing. Use after a procedure is prohibited by the stinging associated with the low pH of properly formulated products.
9. Free Radic Biol Med. 1997;23:85-91.
17. J Invest Dermatol. 1991;96:587.
Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in the Design District in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote the textbook “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002), and a book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). Her latest book, “Cosmeceuticals and Cosmetic Ingredients,” was published in November 2014. Dr. Baumann has received funding for clinical grants from Allergan, Aveeno, Avon Products, Evolus, Galderma, GlaxoSmithKline, Kythera Biopharmaceuticals, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Topix Pharmaceuticals, and Unilever.