Choosing a sunscreen for Bangladesh's sun

If you only change one thing in your skincare, make it this one. Dark spots are the number one concern on our skin test: by mid-October, 60% of the 315 people who took it put them first. Every serum sold for dark spots works against the sun, and without sunscreen the sun wins.

The good news is that the sunscreens sold now are nothing like the thick, white, sticky creams most of us grew up avoiding.

What the numbers on the bottle mean

SPF measures protection from UVB, the rays that burn. SPF 30 blocks roughly 97% of UVB and SPF 50 about 98%. That gap sounds small, but almost nobody applies as much as the test uses, so starting higher leaves you more room for error. In Bangladesh, where the UV index sits high for most of the year, we'd pick SPF 50.

PA measures protection from UVA, the rays that tan and darken. UVA is the part that matters most for dark spots, because it gets through clouds and window glass. PA+++ is good, PA++++ is the highest rating. Many American sunscreens print "broad spectrum" instead of a PA rating, which tells you there's some UVA protection but not how much.

White cast, and why it happens

Mineral sunscreens use zinc oxide or titanium dioxide, which sit on top of the skin and reflect light. On medium and deep skin that often shows as a grey or purple film, which is why so many people here gave up on sunscreen after one try.

Chemical (or "organic") filters absorb UV instead, and they go on clear. Most Korean and Japanese sunscreens use them, which is a big part of why they took off here. If white cast has put you off before, a chemical-filter sunscreen is the fix. If your skin reacts to chemical filters, which some sensitive skin does, a tinted mineral sunscreen is the other way round it.

Matching the texture to your skin

The best sunscreen is the one you'll put on every single morning, so texture matters more than the brand.

• Oily or combination skin: a watery gel that dries matte. Beauty of Joseon Relief Sun Aqua-Fresh was made for exactly this, and the MISSHA All Around Safe Block Aqua Sun Gel feels like almost nothing.
• Normal skin, or anyone who wants one sunscreen for everything: Beauty of Joseon Relief Sun: Rice + Probiotics sinks in like a light lotion with a soft glow.
• Dry or dehydrated skin: SKIN1004 Hyalu-Cica Water-Fit Sun Serum pours like an essence and has hyaluronic acid in it, so it doubles as a moisture step.
• Very humid days and long commutes: Bioré UV Aqua Rich Watery Essence is the one Japan has bought more than any other, and it's the lightest of the lot.

If you're not sure, buy the smallest size first. A sunscreen that pills, stings your eyes or turns shiny by eleven isn't going to get used, however good the reviews are.

How much, and how often

This is where most people go wrong. Squeeze two lines of sunscreen along your index and middle fingers. That's about the right amount for face and neck. It feels like a lot the first week, then it doesn't.

Put it on as the last step of your morning routine, after moisturiser, and give it a minute before makeup. Reapply if you're going out again after lunch, if you've been sweating, or if you've wiped your face. Over makeup, a sunscreen stick or a fresh layer patted on lightly is easier than starting again.

If you're at a desk all day away from windows, the morning layer is mostly enough. If you sit by a window or travel by rickshaw or CNG in the afternoon, reapply.

Taking it off at night

Today's sunscreens are built to stay put through sweat, which also means a face wash alone often leaves some behind. That film is behind a lot of small bumps on the forehead and chin. At night, massage a cleansing oil like the SKIN1004 Madagascar Centella Light Cleansing Oil over dry skin, add a little water until it turns milky, rinse, then use your normal cleanser. Our routine order guide has the full night routine.

A few things people tell themselves

"My moisturiser has SPF 15." It helps, but nobody uses enough moisturiser to get the number on the label, and SPF 15 is low for here.

"Brown skin doesn't need sunscreen." It doesn't burn as easily, but it tans and darkens more easily, and melasma and acne marks are more common on it, not less.

"It's cloudy, so I'll skip it." Most UVA gets through cloud. The monsoon is when a lot of people lose the gains they made in winter.

"Sunscreen makes me break out." Usually it's the wrong texture or it isn't being removed properly at night. Try a lighter gel and an oil cleanse before giving up.

We sell every sunscreen named here, so weigh our picks with that in mind. If any sunscreen stings, burns or brings out a rash, stop using it, and see a dermatologist if your skin reacts to several.