Sparassis crispa (SC) is an edible mushroom with various medicinal properties. In this study, we investigated to determine whether SC would affect skin conditions in rats and humans. Oral administration of SC increased both turnover of the stratum corneum and dermal soluble collagen content in collagen synthetic activity-reduced model rats. To investigate the effects of oral intake of SC in humans, we performed a randomized, double-blind, placebo-controlled study. We found that cheek transepidermal water loss was significantly lower in the experimental group than in the control group at 4 weeks of ingestion. This study suggests that SC is effective and safe for the improvement of skin conditions.