Notes on reading a food label, what the numbers on a pack actually mean, and how the Filtizy score is built.
What each over-the-counter acne active does, the concentrations that work, why 2.5 per cent benzoyl peroxide is usually enough, and the signs that mean a dermatologist rather than another product.
How retinol, retinaldehyde, adapalene and tretinoin differ in strength, how to start without wrecking your barrier, what the purge really is, and who should not use them at all.
L-ascorbic acid versus the derivatives, the pH and packaging that decide whether a serum survives, what vitamin C is actually good for, and how to tell an oxidised bottle from a working one.
What niacinamide is supported for, the concentrations that matter, the myth about mixing it with vitamin C, and how to fit it into a routine without irritating your skin.
