Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage

BACKGROUND. Aging of the population, in particular the "baby boomers," has resulted in increased interest in methods of reversal of photodamage. Non-invasive treatments are in high demand, and our knowledge of mechanisms of photodamage to skin, protection of the skin, and repair of photodamage are becoming more sophisticated and complex. OBJECTIVE. The objective of this study is to determine if the topical use of a vitamin C preparation can stimulate the skin to repair photodamage and result in clinically visible differences, as well as microscopically visible improvement. METHODS. Ten patients applied in a double-blind manner a newly formulated vitamin C complex having 10% ascorbic acid (water soluble) and 7% tetrahexyldecyl ascorbate (lipid soluble) in an anhydrous polysilicone gel base to one-half of the face and the inactive polysilicone gel base to the opposite side. Clincial evaluation of wrinkling, pigmentation, inflammation, and hydration was performed prior to the study and at weeks 4, 8, and 12. Two mm punch biopsies of the lateral cheeks were performed at 12 weeks in four patients and stained with hematoxylin and eosin, as well as in situ hybridization studies using an anti-sense probe for mRNA for type I collagen. A questionnaire was also completed by each patient. RESULTS. A statistically significant improvement of the vitamin C-treated side was seen in the decreased photoaging scores of the cheeks (P = 0.006) and the peri-oral area (P = 0.01). The peri-orbital area improved bilaterally, probably indicating improved hydration. The overall facial improvement of the vitamin C side was statistically significant (P = 0.01). Biopsies showed increased Grenz zone collagen, as well as increased staining for mRNA for type I collagen. No patients were found to have any evidence of inflammation. Hydration was improved bilaterally. Four patients felt that the vitamin C-treated side improved unilaterally. No patient felt the placebo side showed unilateral improvement. CONCLUSION. This formulation of vitamin C results in clinically visible and statistically significant improvement in wrinkling when used topically for 12 weeks. This clinical improvement correlates with biopsy evidence of new collagen formation.