Phycocyanin Reduces Transepidermal Water Loss and Improves Skin Barrier Functionin Healthy Subjects―A Randomized, Double—blind, Placebo—controlled, Parallel—group Comparison Trial―

Objective　Phycocyanin, a biliprotein, possesses antioxidant and anti-inflammatory properties, and, thus, is a promising food substance with various functions for health promotion. The present study investigated the effects of phycocyanin derived from Spirulina on skin function in healthy subjects in a randomized, double-blind, placebo-controlled trial. Methods　Ninety-six subjects were randomly assigned to the test food 410 mg of phycocyanin （C-phycocyanin 300 mg, allophycocyanin 110 mg）and placebo groups. The test food and placebo were administered to the respective groups for 8 weeks. Transepidermal water loss （TEWL）was the primary outcome, and the visual analogue scale（VAS）was the other outcome. Results Among subjects with a TEWL level between 10 g╱m2╱hr and higher to less than 20 g╱m2╱hr（normal value in healthy human）at 0 weeks, TEWL levels at 8 weeks were significantly lower in the test food group than in the placebo group. In the VAS, scores for skin elasticity and skin gloss at 4 and 8 weeks and those for skin moisture at 8 weeks were significantly higher in the test food group than in the placebo group. Conclusion　The administration of 410 mg of phycocyanin（C-phycocyanin 300 mg, allophycocyanin 110 mg）for 8 weeks reduced TEWL and improved skin barrier function in healthy subjects. Furthermore, the effects of phycocyanin on skin function were also detected physically in the VAS. （UMIN ID: 000035205）