Sleep deprivation decreases the beard-hair growth in man

Ten young men underwent a sleep deprivation of 48 h which resulted in a 19 percent decrease of beard-hair growth. This effect, reflecting the lowering of protein synthesis during sleep deprivation, was presumably related to hormonal disturbance, namely depression of growth hormone release, decrease of dihydroxytestosterone availability or increase of sympathetic tone and/or corticoids.