We know more about sunscreen than ever before. So why are so many women still getting it wrong?

I am probably the worst poster girl for sun protection. As teenagers, my friends and I would spend weekends by the pool, deliberately baking ourselves in the sun. This was in the 1990s, and being tan equalled being one of the “cool girls”.

To my teenage brain, it made perfect sense that burning and peeling my skin would make the scars disappear. Yes, it was stupid. I’d like to say I’ve become much more sensible since then. I now know what ultraviolet rays do to the skin; I’ve interviewed enough dermatologists over the years to recite the advice: Wear sunscreen every day, reapply and don’t forget your neck, ears, or any part of the body that’s not covered by clothing.

Knowing, unfortunately, isn’t the same as doing. Two to three days a week, I’m at a rugby field, watching my kid train or compete. I never forget the mouth guard. Definitely not the 2-litre water bottle. Or the deodorant.

But the one thing I routinely forget is sunscreen. I don’t enjoy wearing it. I don’t like the sticky feeling it leaves on my skin. Sometimes I’ll make the token effort and slap some on my face before leaving the house. But I rarely remember to apply sunscreen to the rest of my body, much less bring along a bottle with me.

My feet now have permanent tan lines in the exact shape of my sandals, and my cheeks and arms are freckled with brown spots. A couple of months ago, I went to get some of the freckles on my face lasered off. I’ve been seeing the same aesthetic doctor for years, so she knows she can be blunt.

“If I laser all this off and you still don’t wear sunscreen, don’t come back,” she said. “You’ll just be wasting your money.” She was right to scold me. Like a lot of women, I spend more money than I care to admit on skincare. But it’s pointless spending hundreds of dollars reversing sun damage if I don’t bother doing the one thing that prevents it in the first place.

SPF, PA ratings and UVA vs UVB: What you need to know

Apparently, I’m not the only one slacking off on this. According to a 2019 study by researchers at the NUS Saw Swee Hock School of Public Health and National Skin Centre, only 23.9 per cent of adults in Singapore use sunscreen. Despite living in Singapore, where the UV Index regularly reaches “Very High” or “Extreme” levels between 11am and 3pm on days with little cloud cover, many of us still don’t make sunscreen a daily habit.

Which is ironic, considering there’s an abundance of information now about sun protection and skin cancer. If so many of us know we should be wearing sunscreen, why then aren’t we doing it?

For starters, it can be intimidating just choosing what to buy. There are so many acronyms and numbers. I don’t have the slightest clue if an S$8 SPF50 PA++++ lotion is better than a S$60 SPF50+ serum with protection against UVB, UVA and HEV Blue Light. Even the basics remain surprisingly misunderstood.

Take, for example, SPF (sun protection factor), which measures how well a product protects your skin against sunburn from UVB (ultraviolet B) rays. Many people assume SPF100 must be twice as good as SPF50. They’re wrong.

“A simple way to view it is by how much UV radiation it blocks,” says dermatologist Dr Tan Siew Kiang of The Dermatology Practice. “SPF15 filters about 93 per cent of UVB rays, SPF30 blocks around 97 per cent, SPF50 blocks about 98 per cent. No sunscreen blocks 100 per cent of UVB rays.”

That is also why the US Food and Drug Administration no longer allows companies to market products as “sunblock”. The term suggested complete protection, which simply isn’t possible.

Another thing to keep in mind is that SPF only protects against UVB rays, and not UVA, which can pierce through clouds, penetrate glass windows and cause premature ageing, pigmentation, DNA damage and skin cancer.

“UVA rays make up 95 per cent of the UV rays that reach the earth’s surface,” said Dr Rachel Ho, an aesthetic doctor and medical director of The Skin Longevity Clinic. “Given Singapore’s high UV index, having UVA protection in your sunscreen is necessary.”

This is where the PA rating comes in. The PA system, which stands for Protection Grade of UVA, tells you at a glance how much protection a product gives against UVA rays. The more plus signs, the stronger the protection, with PA++++ offering the highest level currently available.

“Choose sunscreens with PA++++ rating, combined with SPF50, to give all-round protection against both UVA and UVB,” said Dr Stephanie Ho of Stephanie Ho Dermatology.

Mineral vs chemical sunscreen, how much to apply, and the spots everyone misses

Just when you think you’ve finally understood SPF and PA, you’re confronted with another choice: mineral or chemical sunscreen. Social media has turned this into a debate. One camp insists chemical sunscreens interfere with the body’s natural hormone production. The other dismisses mineral sunscreens as thick and chalky.

Mineral sunscreens use ingredients such as zinc oxide and titanium dioxide that sit on the surface of the skin to protect it from UV rays. Chemical sunscreens work differently, absorbing UV radiation before it damages the skin.

If you have allergies or sensitive skin, said Dr Stephanie Ho, then mineral sunscreens might be less irritating. Chemical sunscreens, on the other hand, are often lighter and blend invisibly under makeup, making them more appealing for everyday use.

“The evidence we have today shows that both mineral and chemical sunscreens are safe,” said Dr Tan, who personally uses a lightweight chemical sunscreen for daily wear and a water-resistant zinc-based mineral sunscreen spray for swimming.

Choosing the right sunscreen is only the first step; where you apply it matters just as much. The list of commonly forgotten spots is surprisingly long: ears, eyelids, lips, neck, chest, the backs of the hands, the tops of the feet, and even the scalp. “These missed areas correspond to the high-risk sites for skin cancer. These are areas I always remind my patients to protect,” said Dr Stephanie Ho.

Dr Lynn Teo, consultant dermatologist and medical director of The Dermatology Practice, recalls patients returning from hiking in the mountains in Austria with scalp sunburns. “(The weather was) nice and cool,” she said. “But high altitude and prolonged exposure without a hat led to the sunburn.”

But even if you remember every exposed patch of skin, many of us are still not applying enough sunscreen.

To get the SPF protection printed on the bottle, you should be using two milligrams of sunscreen per square centimetre of skin. For the face and neck, this translates to the “two-finger rule”, which is two full strips of sunscreen squeezed along the length of your index and middle fingers.

“If you only apply a tiny dab, you aren’t just cutting the protection in half – the relationship is exponential. A tiny dab of SPF50 can plummet the actual protection down to an SPF of 5 or 10, leaving you largely unprotected,” said Dr Tan.

How often should you reapply sunscreen?

Most dermatologists recommend reapplying every two hours outdoors, or sooner if you’ve been swimming or sweating a lot. If you’re spending the day in an office, reapplication is less critical.

“To be honest, even I myself do not reapply my sunscreen in Singapore because I spend the whole day indoors,” said Dr Tan. “No one is going to remove and redo a full face of makeup every two hours.”

Dr Rachel Ho agrees that while reapplication is ideal, it isn’t always realistic. She advises combining sunscreen with other forms of protection, such as seeking shade, carrying an umbrella and wearing UPF-rated clothing.

“The old adage ‘prevention is better than cure’ is so true in my line of work,” said Dr Teo. “Skin cancers, once they appear, are really too late. The damage is done to any area of the skin and we have to keep monitoring to keep abreast of new ones. Pigmentation, once they appear, also needs maintenance as it always recurs. Skin ageing from UV exposure – well, there’s no cure for that. Reversal we try always, complete reversal never.”

That brings me back to the rugby field. I can’t completely undo the past, but from now on, sunscreen is going into the bag with the mouthguard, the water bottle and the deodorant.