Oral Intake and Topical Application of Hyaluronic Acid Ameliorates Skin Aging Signs: Efficacy Results of a Placebo-Controlled In & Out Trial

Hyaluronic acid (HA) content in the skin progressively decreases with age, thus its supplementation - either topical, oral and by subcutaneous injection - represents a first line intervention to ameliorate skin aging signs. The present multicenter randomized placebo-controlled trial (RCT) evaluated the skin antiaging efficacy of an In&Out treatment, i.e. a concomitant topical, through a cosmetic cream, and oral administration of a specifically designed HAs, the Full Spectrum HAs (FS-HA), in a multiethnic population by instrumental measurements and clinical assessments. Efficacy of FS-HAs was evaluated also in groups receiving FS-HA in a single administration route and in presence of the placebo in the counterpart route. The above treatment scheme was applied for fifty-six days to eighty-eight adult subjects, equally divided in four groups. Treatments containing at least one FS-HA molecule showed progressive and significant intragroup ameliorations of all instrumental skin parameters evaluated. The In&Out treatment resulted in a higher improvement with respect to the two other active groups and in significant intergroup differences with respect to its placebo counterpart. FS-HA treatments resulted, as well, in significant improvements of clinical parameters that correlated with the subjects’ appreciation recorded by a Self-Assessment, hence confirming that the In&Out administration of FS-HA represents an interesting approach to counteract skin aging signs.