5 reasons for not neglecting sun protection

Sun exposure carries a real cost to skin health, and the case for guarding against it is straightforward: it prevents burns, slows visible ageing, and lowers long-term cancer risk. It also happens to be the cheapest and best-evidenced step in any skincare routine.

Outdoor life is not the problem: picnics, cycling, gardening, a day at the pool are all worth having. What matters is that every one of them carries an ultraviolet dose, and that dose accumulates over a lifetime whether or not you notice it at the time.

Here are five reasons not to let sun protection slide.

Reduce the risk of skin cancer

Cumulative UV exposure is the principal modifiable risk factor for skin cancer. UV-B damages DNA directly in the epidermis by forming pyrimidine dimers; UV-A contributes through reactive oxygen species deeper in the skin. Basal and squamous cell carcinomas are common and usually highly treatable when caught early. Melanoma is far less common but far more serious once it has spread, and episodes of blistering sunburn, particularly in childhood, are an established risk factor for it. Regular sunscreen use reduces risk; it does not remove it.

Minimize uneven pigmentation

Daily use helps keep tone even by limiting the UV-driven melanogenesis behind solar lentigines, mottled pigmentation and general blotchiness, and by reducing the flares that make melasma so difficult to manage. It is preventive rather than corrective: sunscreen stops existing marks deepening and slows new ones appearing, but does not clear what is already there. For that side of the problem, see ingredients for tone and hyperpigmentation.

Prevent sunburn

Susceptibility varies enormously with skin phototype, and it is not fixed. A great many common medications are photosensitising (some antibiotics, thiazide diuretics, certain NSAIDs, retinoids and several acne treatments among them) and can turn an ordinary afternoon into a burn. Sunburn is also not merely uncomfortable; it is visible evidence of DNA damage. Applying before you leave the house is the simplest way to avoid finding out the hard way.

Maintain the younger looks of your skin

Most of what people read as ageing on the face, neck and hands is photo-ageing, not chronological ageing: degraded collagen and elastin, coarse texture, laxity and pigment change, driven largely by UV-A. This is the best-evidenced cosmetic benefit in the category: randomised trials of daily broad-spectrum sunscreen show measurably slower accumulation of fine lines and pigmentation than no sunscreen. Note the mechanism, though: filters absorb UV energy; they do not "block" it, and no product stops all of it.

Support the skin barrier

UV exposure disrupts barrier function and increases water loss, so protecting skin protects hydration indirectly. Many sunscreens also carry humectants and emollients in the base, which is convenient, but check the label rather than assuming, and if your skin is dry, treat moisturising and UV protection as two jobs that a single product may or may not do well. See skin barrier and hydration.

Use a broad-spectrum SPF 30 or higher daily, apply enough of it, and reapply. Sun protection is a habit rather than an event.