Sleep
Also known as sleep hygiene, recovery
The highest-return free intervention available. Nothing else you do works properly on five hours a night.
Free.
How it works
Growth hormone is released predominantly during slow-wave sleep and drives tissue repair. Sleep deprivation raises cortisol, which degrades collagen and promotes visceral fat storage; it also impairs skin barrier recovery, increases periorbital fluid retention and vasodilation (dark circles and puffiness), and disrupts the hunger hormones leptin and ghrelin.
How it's used
Aim for 7–9 hours at a consistent time. Keep the room dark and cool. Get bright light within an hour of waking and cut caffeine 8–10 hours before bed. Sleeping on your back reduces both facial fluid pooling and sleep-crease lines. Fix the schedule before buying any supplement.
Trade-offs
In favour
- Free
- Improves skin quality, under-eye appearance and body composition simultaneously
- Enables recovery from training
- Improves mood, adherence and decision-making — which improves everything else
Against
- Requires genuine lifestyle restructuring
- Effects on appearance are gradual
- Easily sabotaged by shift work or young children
Risks and side effects
- Chronic deprivation carries serious cardiometabolic and mental health consequences
- Untreated sleep apnoea is a medical issue and needs investigation rather than lifestyle tweaks
How good is the evidence?
Very strong evidence linking sleep to skin barrier function, perceived attractiveness, cortisol regulation and body composition.
Sources
Sources point to guideline bodies and literature searches rather than single papers, so they stay accurate as the evidence moves.