Background: Hyaluronan (HA) has critical moisturizing property and high water retention capacity especially for human skin. This study aimed to evaluate the effect of oral intake of HA.
Methods: The mean molecular weight (MW) of HA is 2 k and 300 k. Sixty Japanese male and female subjects aged 22-59 years who presented with crow's feet wrinkles were randomly assigned to the HA 2 k or HA 300 k at 120 mg/day or the placebo group. The subjects were administered HA at a rate of 120 mg/day or a placebo for 12 weeks. The skin wrinkles were evaluated by image analysis of skin wrinkle replicas, and their skin condition was evaluated using a questionnaire survey.
Results: During the study period, the HA groups showed better level of the whole sulcus volume ratio, wrinkle area ratio, and wrinkle volume ratio than the placebo group. After 8 weeks of ingestion, the HA 300 k group showed significantly diminished wrinkles compared with the placebo group. Skin luster and suppleness significantly improved after 12 weeks in all groups compared with the baseline.
Conclusion: The results suggest that oral HA (both HA 2 k and HA 300 k) inhibits skin wrinkles and improves skin condition.
Keywords: dietary supplement; hyaluronic acid; molecular weight; skin; wrinkle volume.