All guides

Each guide answers one buying question and shows the figures behind the answer.

3 guides

Stacked teal glass body cream jars with brushed gold lids on a mirrored shop shelf, one marked TESTER

Budget and prices

What a premium face cream actually costs per use

Price per jar hides the figure that matters. Divide by millilitres, multiply by your real dose, and a $180 jar turns into $3.60 a day and $1,314 a year.

Updated 11/3/2026 · 8 min

Photo: Pittigrilli · CC BY-SA 4.0 · Wikimedia Commons

Black-and-white photograph of four square glass toiletry bottles with ornate labels for shampoo, rose cream and astringent lotion

Ingredients

Reading a skincare ingredient list for what it can actually tell you

Ingredients are listed in descending order until 1 percent, then in any order. Here is which parts of a cosmetic label carry information and which do not.

Updated 11/3/2026 · 8 min

Photo: National Photo Company Collection · Public domain · Wikimedia Commons

Two faces of a triangular pottery fragment, pale outside and orange inside, beside a centimetre scale bar

Reactions and irritation

Acids and sun sensitivity: introducing an active without a reaction

FDA-reported studies put AHA sun sensitivity at 18 percent after four weeks, lasting a week after you stop. Here is how that shapes a sensible introduction.

Updated 11/3/2026 · 8 min

Photo: LCC, Lisa Keys, 2005-12-09 14:51:24 · CC BY-SA 4.0 · Wikimedia Commons