Reference
Skincare reference charts
The numbers, fact-checked and table-shaped. Strengths, percentages, and pairings you can actually look up, no fluff, no invented figures.
Retinoid strength equivalence chart
Retinol %, retinaldehyde, and adapalene mapped to prescription tretinoin 0.025 / 0.05 / 0.1%, plus a beginner-to-advanced ramp.
View chart → SunscreenSPF protection chart
Exactly what % of UVB each SPF blocks: SPF 15 = 93.3%, 30 = 96.7%, 50 = 98%, 100 = 99%, and the one formula behind it.
View chart → ExfoliantsAHA / BHA acid concentration guide
Glycolic, lactic, mandelic, salicylic, azelaic, and PHA percentage ranges for daily use vs in-office peels, by skin type.
View chart → LayeringIngredient layering & conflict chart
What to combine, what to separate, and which "you can't mix these" rules are debunked myths (yes, vitamin C + niacinamide is fine).
View chart → AntioxidantsVitamin C & niacinamide concentration guide
Effective percentages by form and skin type: L-ascorbic 10–20%, gentle derivatives 5–10%, niacinamide 2–5%.
View chart →These charts present published standards and broad dermatology and cosmetic-science consensus for education only. They are not medical advice. For anything specific to your skin, history, or a medical condition, consult a board-certified dermatologist.
