Improvement of skin conditions by ingestion of Aspergillus kawachii (Koji) extract containing 14-dehydroergosterol in a randomized, double-blind, controlled trial.

Purpose: The present study examined the effect of ingestion of Koji extract containing 14-dehydroergosterol (14-DHE), prepared from Aspergillus kawachii NBRC4308, on improvement of skin conditions among healthy volunteers.

Subjects and methods: In a randomized, double-blind, placebo-controlled, parallel-group study, 70 healthy adult women who felt that their skin was dry ingested either a placebo dietary supplement or Koji extract (200 mg/day) supplement containing 0.1% 14-DHE for 12 weeks. Throughout the treatment period and for 4 weeks afterward, objective indicators - including moisture content of the stratum corneum, trans-epidermal water loss (TEWL), and skin wrinkles - were evaluated; in addition, the subjects answered a questionnaire on their skin conditions with ratings on a visual analog scale. Statistical analysis was conducted on the basis of differences from baseline scores.

Results: Compared with the placebo group, the Koji extract group showed significantly increased forearm moisture at 4, 8, and 16 weeks ( p < 0.05 on unpaired t -test). The questionnaire survey showed a marked improvement in skin conditions, particularly crow's feet, in the Koji extract group versus the placebo group at 8 weeks ( p < 0.05 by unpaired t -test). Furthermore, the Koji extract group showed a trend ( p < 0.10) toward improvement in skin moisture (at 4 weeks), dryness around the eyes/mouth (at 4 weeks), and overall skin condition (at 8 weeks) versus the placebo group.

Conclusion: Ingestion of Koji extract containing 14-DHE was demonstrated to have positive effects toward improving skin conditions - in particular, on increasing skin moisture in the stratum corneum.