Sunscreen is a cream, lotion or spray that protects skin from ultraviolet (UV) rays in sunlight. UVB rays burn the skin and cause sunburn, while UVA rays penetrate deeper, causing premature aging (wrinkles, pigmentation) – and both contribute to skin cancer.
Sunscreens contain UV filters: physical (mineral) blockers such as zinc oxide or titanium dioxide that reflect sunlight, or chemical absorbers that soak up UV light. Most modern sunscreens mix both for broad-spectrum (UVA+UVB) protection.
The SPF number indicates UVB protection (SPF30 means it blocks roughly 97% of UVB), and a 4–5 star or “UVA” label ensures strong UVA defence. Using sunscreen correctly (liberally and often) is key, as a thin layer greatly reduces its effectiveness.
Why sunscreen protects skin health
Sunscreen helps prevent sunburn and long-term skin damage. Even in the UK, you can burn on cold or cloudy days. Sunburn increases your risk of skin cancer because UV causes DNA damage.
Regular sun exposure without protection accelerates skin aging: UVA rays penetrate deeply and trigger oxidative damage that leads to wrinkles and brown spots. Most critically, UV exposure is the main cause of skin cancer; in the UK up to 9 in 10 melanoma cases (the deadliest form) could be prevented by safe sun habits, according to Cancer Research UK. By blocking UV, sunscreen reduces these risks, making it an essential tool for protecting skin health.
Sun exposure, vitamin D and NHS guidance
The NHS advises balancing sun protection with vitamin D needs. In the UK, sunlight is the main source of vitamin D, vital for strong bones and muscles. From about late March/early April until the end of September, most people can make enough vitamin D from brief, casual sun exposure. During these months, you may choose not to wear sunscreen on short outings (like walking to work) in order to boost vitamin D, as long as you avoid burning.
However, from October to March the sun’s rays are too weak for vitamin D synthesis, so everyone in the UK is advised to take a daily supplement of 10 micrograms (400 IU) of vitamin D during the autumn and winter. In fact, those at higher risk of deficiency – including people with darker skin, the elderly, housebound people or those covering up outdoors – should consider year-round supplements. In practice, short, unprotected sun exposure in summer is enough for vitamin D, but sunscreen should be worn for longer periods outside.
Skin cancer in the UK
Skin cancer is increasing in the UK, largely due to past sun exposure. Melanoma is now the fifth most common cancer in the UK (about 5% of new cases).
There are roughly 17,500 new melanoma cases per year in the UK (2017–2019 average), and incidence has more than doubled since the 1990s. Men are slightly more affected than women (making it the 4th most common cancer in men). Worryingly, by 2040, melanoma cases could rise by about 50% without better prevention. Importantly, around 86–90% of melanomas are preventable.
Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) – collectively called non-melanoma skin cancers – are far more common than melanoma. They usually occur on sun-exposed areas, such as the face, arms or legs. BCC (the most common) often appears as a small flesh-coloured lump or scaly patch, while SCC may look like a crusty or inflamed spot.
In contrast, melanoma often begins as an irregularly pigmented mole or spot. Because BCC and SCC tend not to metastasize, they are rarely fatal, but they can grow and cause local damage. All types are linked to UV exposure; for example, if you have many moles you are advised to take extra care in the sun. In short, skin cancer is now one of the fastest-growing cancers in the UK, highlighting why sunscreen (along with shade and clothing) is so important.
Pros and cons of sun exposure
Sunlight has both benefits and risks. On the plus side, UVB radiation triggers vitamin D production (essential for bone health, preventing rickets and osteomalacia). Sunlight also boosts our mood and can help regulate our sleep-wake cycle, and some research suggests modest benefits for heart health or immunity.
However, these benefits are achievable with limited exposure. On the minus side, too much UV is harmful. Beyond skin cancer and sunburn, UV exposure accelerates skin ageing (wrinkles, loss of elasticity, brown spots) due to DNA and collagen damage, as well as damaging the eyes (contributing to cataracts and retinal harm). Given that vitamin D can be obtained in summer by short exposures or supplements, and from diet or vitamin D-containing foods, the cons of unprotected sun exposure often outweigh the pros.
Sun safety tips
To enjoy the sun safely, use multiple protective measures whenever UV levels are moderate or high (UV index ≥3):
- Seek shade: Spend time under umbrellas, trees or indoors between 11am and 3pm (the sun’s strongest hours in UK spring – autumn).
- Cover up: Wear tightly woven clothing covering arms and legs, a broad-brimmed hat and UV-blocking sunglasses.
- Sunscreen: Apply a broad-spectrum sunscreen (at least SPF 30 with 4–5 star UVA rating) to all exposed skin. Use sunscreen as a “last line” on areas you can’t cover.
Never let yourself burn. Even if it’s cloudy, remember that up to 90% of UV radiation can penetrate cloud cover and cause skin damage. In the UK, reliable sun protection is generally only needed in the warmer months (mid-March to mid-October), but if you’re skiing or abroad, strong UV can occur at other times.
Also note that glass blocks UVB but not all UVA: sitting by a sunny window (for example at home or driving) can still expose you to UVA rays over time. In short, whenever you’re outside long enough to risk burning, use shade, clothing and sunscreen together.
Choosing sunscreen: SPF, broad-spectrum and ingredients
When choosing sunscreen, look for broad-spectrum UVA/UVB protection. Labels should state SPF 30 or higher (some recommend SPF 50+). Also check the UVA seal or star-rating (UK sunscreens show up to 5 stars for UVA). Use a higher SPF if you burn easily or will spend a long time in strong sun – but remember that no sunscreen is 100% protective. Avoid products past their expiry date, and reapply regularly (at least every 2 hours and after swimming or sweating).
Sunscreens vary by active ingredients: Mineral (physical) sunscreens contain zinc oxide or titanium dioxide. These start working immediately by reflecting UV rays, and tend to be gentler for very young or sensitive skin. Chemical sunscreens contain organic molecules (like avobenzone, octinoxate, octocrylene, etc.) that absorb UV and convert it to heat. Both types can be effective; many products blend them. If you have allergies or young children, mineral-only (often marketed as “suitable for babies”) may be preferred. In any case, apply sunscreen generously – adults need about 6 to 8 teaspoons to cover the body – 15–30 minutes before sun exposure, and remember to reapply. Sunscreen should complement, not replace, shade and clothing.
Sunscreen for babies and children
Children’s skin is thinner and more sensitive, so young children need extra sun care. Babies under 6 months should be kept completely out of direct sunlight (use shade and clothing, not sunscreen). For older babies and children (March–October), make sure to cover up (long sleeves/pants), keep them in the shade (especially 11am–3pm), and apply a high-factor (SPF 30+) sunscreen to any exposed skin. A broad-brimmed hat and sunglasses should be used.
The NHS explicitly warns that “damage caused by repeated exposure in childhood could lead to skin cancer later in life”, so it’s vital to avoid any sunburn on children. (Also note: all children under 5 are advised to take a daily vitamin D supplement throughout the year.)
What to do if you get sunburned
If you do get sunburned, act quickly to help your skin heal. The NHS advises:
- Cool down and soothe – take cool baths or sponging with water, then apply after-sun lotion or gel (aloe vera is soothing).
- Ease pain/inflammation – paracetamol or ibuprofen can reduce discomfort and swelling.
- Drink plenty of fluids to stay hydrated.
- Stay out of the sun until the redness goes away.
- Blistered or severe sunburn may require medical attention: see a doctor if blisters are widespread, the skin starts to weep, or you feel systemically unwell (fever, chills).
Remember: after-sun products only soothe symptoms; they cannot repair DNA damage. Preventing sunburn with proper sun safety is far better than treating it afterward.
Checking moles and skin changes
Always keep an eye on your skin. The NHS recommends that anyone with moles or freckles should perform regular self-checks. Look for any changes in existing moles or new growths. See your GP promptly if you notice a mole that changes in size, shape or colour, becomes itchy, painful, crusted or bleeds, or if any new unusual spot appears and does not fade after a few weeks. These can be signs of melanoma or other skin cancers.
Early detection is crucial: finding a melanoma “as early as possible can mean it’s easier to treat”. Your doctor may apply the “ABCDE” rule (Asymmetry, Border, Colour, Diameter, Evolving) when examining a mole. In practice, never delay – even a small suspicion is worth checking, as most skin cancers caught early are highly treatable. Routine GP checks for high-risk patients (e.g. many moles or previous skin cancer) can also help catch changes early.
Stay sun-safe
Sunscreen is an important part of a comprehensive sun-safe strategy. By using SPF30+ broad-spectrum sunscreen together with shade and clothing, families can enjoy outdoor activities while minimising the risks of sunburn and long-term skin damage. Public health guidance in the UK (NHS and Cancer Research UK) consistently emphasises that protecting skin now pays off with healthier skin and a lower risk of cancer later.
