The truth about sunscreen: Myths, science, and smart choices for a South African summer

As summer heats up in South Africa and expats flock home to soak up the sunshine, sunscreen becomes more than skincare – it’s science-backed self-care.

Here’s what research reveals about ageing, cancer myths, and choosing between mineral and chemical sunscreens, especially if you’re arriving from Europe’s cooler climate.

The Sunscreen Debate

Every summer, I hear conflicting advice: “Wear sunscreen – it’s your best defence against ageing,” versus “It’s full of chemicals that cause cancer.”

As someone who loves the sun yet fears the damage it can do, I wanted to understand what the science really says.

What Research Shows

Decades of dermatology research agree – ultraviolet (UV) radiation is the leading external cause of premature ageing and skin cancers.

The World Health Organisation reports that up to 90% of non-melanoma skin cancers and most visible ageing (wrinkles, pigmentation, loss of elasticity) stem from UV exposure, not time itself.

The WHO and the International Agency for Research on Cancer (IARC) confirm that virtually all keratinocyte cancers are attributable to ultraviolet radiation.

Multiple studies – including long-term trials published in the Journal of Clinical Oncology – show that daily sunscreen use reduces melanoma incidence and helps maintain smoother, more even-toned skin.

In other words: sunscreen genuinely slows photoageing and protects against cancer.

And the claim that sunscreen causes cancer? There’s no credible human evidence for it.

Some chemical filters – like oxybenzone or avobenzone – have been detected in the bloodstream in trace amounts, but the US FDA and European regulators emphasise that this does not equate to harm.

The risk of UV damage far outweighs any theoretical chemical concern.

Chemical vs Mineral Sunscreens

Here’s how I simplify the choice:

• Mineral sunscreens (zinc oxide, titanium dioxide) act as physical shields, reflecting and scattering UV rays. They’re photostable, reef-safe, and gentle for sensitive skin – but can leave a pale cast.
  
• Chemical sunscreens absorb UV and convert it to heat. They tend to feel lighter, making them ideal for daily wear. Newer formulas often blend chemical and mineral filters for balanced coverage.
  

Personally, I use a chemical formula broad spectrum SPF 50+ for everyday wear – because comfort and texture mean I’ll actually reapply, which is what really matters.

A Summer Reality Check

South Africa’s UV index often ranks among the world’s highest.

Dermatologists recommend SPF 30 – 50, applied generously and reapplied every two hours. Add shade, hats, and sunglasses for best results.

For expats arriving from Europe – start slow. Your skin’s melanin response may be slower, so take it easy in the first few days.

My Takeaway

This summer, sunscreen isn’t vanity – it’s biology. It prevents DNA damage, slows visible ageing, and helps guard against skin cancer.

The truth?

Science stands firmly behind sunscreen. The only mistake is not using it enough.