The link between sleep and health is adequately established but less well established is the role of sleep in skincare. Sleep is a major factor in skincare that's easily overlooked or approached from a product perspective rather than a unique behavioural opportunity to embrace skin friendly activities that benefit skin in the long run.
In an 8-hour sleep cycle - the staggered release of human growth hormone and melatonin and reduction of cortisol all affect collagen production and help the skin repair but you need the full sleep cycle to accrue these benefits - interrupting sleep is as unhelpful to the skin as it is to other aspects of health and well-being. (I'm looking at you dark circles) While the common emphasis of nighttime products is ingredients that are beneficial for the skin but not excessively stable in daylight like retinols and vitamin c the real opportunity in sleeping beauty is in posture. Though a gel-based overnight mask atop an excellent serum has its merits.
To spend at least a third of your life in an optimal posture for your face has enormous benefits and the best thing to do is sleep on your back without a pillow under your neck on silk sheets with your feet elevated.
Sleeping on your back prevents the skin on your face from being crushed (sorry spooners) - it's not so bad for a short time but 8 hours a day all your life is a routine no topical application can roundly reverse. Sleeping with a pillow renders us in the exact same position we spend most of our waking lives - with text neck. This respite from looking down is meant to open your throat chakra but at the very least does not reinforce the sub-optimal text-neck posture.
Likewise the habit of sleeping with elevated legs fights varicose veins - you have to elevate them above your heart for improved circulation which is 3-4 pillows. Now there's also speculation that this could help with cellulite but this seems like a stretch though it does aid with post workout recovery.
To release the most melanin you need absolute darkness and this means parting with devices on the bed and one way to protect yourself from diffused light is to wear a silk eye mask. Silk sheets keep your neck cool in case you have a predisposition to insomnia which is also effectively handled by sleeping with a fan - especially overthinkers but in general sleeping at slightly cooler temperatures also has the benefit of a little weight loss as the body has to work harder to maintain its temperature.
Now the best of all sleep skin realisations is that there is no such thing as oversleeping - if you sleep long you probably need it and it's far smarter to set an alarm for bedtime and wake up naturally rather than grappling with snooze buttons. Test this out on weekends - see how long you can lie in... if you sleep 10 continuous hours you probably needed that sleep and your skin and reflexes will thank you for the rest.
Where unbruised youth with unstuff’d brain, Doth couch his limbs, there golden sleep doth reign.