Photostability: why some SPF fades in the sun

Some sunscreens quietly lose strength while you sit in the sun. What photostability is, how mineral and chemical filters differ, and how to check your own bottle.

City, screen and office: what your skin actually notices

Pollution, screens and air conditioning get blamed for city skin. Two of those are real. The third is one of the most oversold claims in skincare.

Flying and your skin: what actually happens in the cabin

Cabin air sits at 10 to 20 per cent humidity against the 40 to 60 you are used to. What that does to your skin, and why the hydrating serum in your bag can make it worse.

Glycerin: the dullest ingredient in your routine, and the one doing the most

Glycerin is in nearly every product you own and nobody markets it. It is also one of the best-evidenced ingredients in skincare. Here is why both are true.

Peptides: what they can do, and what they cannot

Peptides get marketed harder than the evidence supports. What they actually do, why they are usually in night products, and where the botox comparison falls apart.

AHA, BHA or PHA: which acid suits your skin

Three acronyms, and the difference comes down to one thing: molecule size. Which acid does what, how often, and the mistake almost everyone makes.

Ceramides: what your skin is missing when everything stings

Skin that suddenly reacts to products that were always fine has not become sensitive. Its barrier is damaged, and that is a different problem with a different fix.

Retinol: why most people start too fast

Most people quit retinol in week two, when the flaking starts. What it does, which form matters, the new EU limit, and how to build it up without the misery.

Niacinamide: what it does, and which percentage you need

Most research works at two to five per cent, not ten. What vitamin B3 does in the skin, why it sits in two of our products, and why the vitamin C warning is outdated.

Hyaluronic acid: why it sometimes leaves your skin drier

Hyaluronic acid attracts water, but from where? Why it works against you in dry air, and how to fix that in two steps.

Vitamin C in skincare: which percentage actually tells you something?

Why fifteen per cent tells you nothing without stability, what vitamin C actually does in the skin, and how to tell when your serum has expired.

Salicylic acid (BHA): what it does for clogged pores

Salicylic acid is an oil-soluble BHA that works inside the pore rather than on top of it. What it does for blackheads and clogged pores, how much is allowed in the EU, and why a rinse-off cleanser ...