Can you still repair sun damage to your skin?

Sun damage is partly reversible, but never completely. UV radiation causes two problems: damage to the DNA in your skin cells and breakdown of the protein fibres that keep your skin firm and supple. Your skin has its own repair system for DNA damage, but it does not work perfectly. Wrinkles and sagging skin caused by the loss of those fibres are not something your body undoes on its own.

Your sleep plays a bigger role than most people think. Skin cells repair UV damage to their DNA largely at night, driven by your biological clock. Poor sleep is associated with less repair and faster skin ageing. Good sleep is therefore not a luxury, but a practical prerequisite for your skin's ability to heal itself.

What does help is a combination of UV protection and good basic skincare. Sunscreen, avoiding peak hours and strengthening your skin barrier slow further damage. Eating enough protein is also a basic requirement: without those building blocks, your skin cannot produce or repair its fibres. This is well supported mechanistically, but the precise clinical effects of individual dietary choices have not yet been quantified exactly.

Experimental treatments are promising, but not yet ready for everyday use. Tiny particles that cells exchange with one another (exosomes) showed impressive results in cell and mouse studies: less DNA damage, fewer wrinkles and greater production of supporting fibres¹. However, no studies in humans exist yet. The same applies to plant extracts that inhibit inflammation in the laboratory: clinical evidence is largely lacking there as well.

On infrared radiation, the part of sunlight without UV, no clear picture has yet emerged. Research discusses both possible damage and possible stimulation of repair, but which effect predominates is unclear^2,3. Whether sunscreens should also protect against it remains an open question.