De schone slaapster:
There is a myth that skin repair happens during sleep and, therefore, lack of sleep makes the skin unable to properly renew and repair itself. Occasionally, this myth is used in promos for night creams that supposedly stimulate skin repair.
In reality, the skin repair and renewal is an ongoing process unrelated to sleep. However, it is true that chronic lack of sleep might have some negative effects on your appearance. Excess of stress hormones caused by the lack of sleep might slow the collagen production in the skin. Also, lack of sleep may alter the regulation of blood vessel tone and thus contribute to puffiness or bags under the eyes. http://www.smartskincare.com/smartchoices/myths/myth_sleep_skin_repair.html
(Dr. Jetske Ultee onderzoeksarts cosmetische dermatologie)