Why the serum is 4% niacinamide, not 10%
Somewhere along the way 10% became a selling point rather than a formulation decision.
Journal
Notes on clay, actives and formulation. Where a piece responds to someone else’s episode, it says so and links to it.
Why clay does not know when to stop
The tightness after a clay mask is not the clay working. It is the clay not stopping.
What 2% salicylic acid actually tells you
The number on the front is the least informative thing about an acid.