Ingredients, Graded
Every ingredient carries the strength of its evidence on the same four-step scale, printed before the pitch. What it does, what concentration matters, who should skip it, and what it cannot be paired with.
Every ingredient here carries a grade for how strong its evidence is, and the grade appears before the description rather than after it. Four steps: how the grading works, including what gets an ingredient left out of this list entirely.
A brand blog will not print the words the evidence is thin, because it is selling the thing. That sentence is most of the value on these pages, so it gets printed here whenever it is true.
How We Rate Skincare Evidence: The Scale, and What Disqualifies an Ingredient
How we rate skincare evidence on every ingredient page: a four-step scale, the rule that keeps it from drifting, and what gets an ingredient left out entirely.
9 min readSkincare Ingredient Conflicts: One Is Documented, and It Has an Exemption
Most skincare ingredient conflicts are unverifiable or describe cumulative irritation. The one with a clinical source comes with an exception nobody repeats.
10 min readSalicylic Acid: One Molecule, Three Sets of Rules, and a Legal Ceiling
Salicylic acid is capped at 2% in over-the-counter acne products. What the safety assessment actually concluded, and the condition attached to it.
10 min readNiacinamide: Better Evidence Than I Had Been Giving It, and Narrower Than the Marketing
Niacinamide has real trial evidence at 2% and 4%, including for sebum. It also has claims it does not support. This page corrects an error made elsewhere here.
11 min readRetinol vs Retinoid: Two Grades on One Page, Because They Are Not the Same Thing
Retinol is one retinoid among several, and the strongest one you can buy without a prescription is a different molecule entirely. Graded separately, on purpose.
12 min readAzelaic Acid: The Active Defined Best by What It Does Not Do
Azelaic acid does not bleach normal skin or clothing, cause photosensitivity or drive antibiotic resistance. One risk falls on the group it helps most.
11 min readBenzoyl Peroxide: The Ingredient That Keeps Antibiotics Working
Benzoyl peroxide does more than clear spots: it limits antibiotic resistance. Why 2.5% is the sensible start, and what the benzene testing found.
11 min readHyaluronic Acid: The Famous Evidence Belongs to a Needle
The clinical chapter on hyaluronic acid is about injections. The serum does humectant work, and the variable it competes on is never printed on a label.
10 min read