The SPF number is noisier than it looks
We sell some of what is named here
Routinae sells some of the products written about here, so read this the way you would read any shop’s opinion of its own shelves. Where we think a cheaper product does the same job we say so, and where the evidence is thin we say that too. Our buying standard is published so you can check the argument against it.
Here is an uncomfortable fact about the most trusted number in skincare: one manufacturer sent a single SPF 100 sunscreen to five different laboratories and got back results between 37 and 75. In 2020, a well-liked Korean sunscreen labelled SPF 50+ measured 19 in independent European testing — a scandal that reshaped how Korean SPF is certified. And you cannot work SPF out from an ingredient list: run real formulas through the maths and the prediction lands wildly off.
This is not a reason to distrust sunscreen. The test method is real, the protection is real, and EU-market products answer to real rules — we wrote about that certification story here. It is a reason not to shop by the number. The difference between a genuine 30 and a genuine 50 is smaller than the marketing implies: roughly 96.7% versus 98% of UVB blocked — at the laboratory dose, which almost nobody wears.
Where protection actually lives:
1. Amount. The labelled number assumes 2 mg per square centimetre — a teaspoon for the face. At half dose, every number on every bottle is fiction. This single variable outweighs everything else on this page.
2. Reapplication. Films break down, sweat off, rub off on collars and phone screens. The two-hour top-up is worth more than twenty label points.
3. Wearability. A texture you enjoy at full dose beats a higher number you ration. This is the whole argument for the modern Korean formulas on our shelf — they made the real amount bearable.
So: buy SPF 50+ when the texture is one you will wear generously — every product we stock qualifies — and then forget the number. The bottle's arithmetic was never the fragile part. Yours is.