Against the actives arms race

Concentration is the easiest number to put on a bottle and the least informative one on it. It says nothing about pH, nothing about vehicle, nothing about whether the molecule reaches the layer it acts on.

A 20% vitamin C at pH 4.2 is a 0% vitamin C with a marketing budget.

We compound to the middle of the published effective range, not the top of it. Where the curve flattens, the extra percent buys irritation and nothing else — and an irritated barrier is a barrier that absorbs unpredictably, which corrupts every other step.