3
Guides published
Each one answers a single buying question.
Independent buying guides
Find out what a premium skincare jar costs per use
For shoppers weighing expensive serums and creams who want the arithmetic before the marketing. Each guide answers one question, cites ingredient and regulatory sources with the date checked, and shows the formula behind the cost-per-use calculator.
3
Calculators
Formula, units and assumptions shown on the page.
9
Sources cited
Each with the date the link was checked.
9
Photographs
Free-licence images, photographer credited.
Browse by question
How to choose
The decisions that actually change what you end up with.
0
Photo: Siyoung In · CC BY-SA 4.0 · Wikimedia Commons
Ingredients
What is on the label and what it does.
1
Photo: Kristoferb / Kristoferb at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons
Routines
Order, frequency and how long a bottle lasts.
0
Photo: LCC, Lisa Keys, 2005-12-09 14:51:24 · CC BY-SA 4.0 · Wikimedia Commons
Budget and prices
What the total comes to once everything is counted.
1
Photo: North Lincolnshire Museum, Lisa Staves, 2007-07-30 10:02:33 · CC BY-SA 4.0 · Wikimedia Commons
Evidence
What the published evidence does and does not show.
0
Photo: Pittigrilli · CC BY-SA 4.0 · Wikimedia Commons
Reactions and irritation
Reactions, patch testing and when to stop.
1
Photo: Pittigrilli · CC BY-SA 4.0 · Wikimedia Commons
Start here
Each guide answers one buying question and shows the figures behind the answer.
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.
Photo: Pittigrilli · CC BY-SA 4.0 · Wikimedia Commons
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.
Photo: National Photo Company Collection · Public domain · Wikimedia Commons
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.
Photo: LCC, Lisa Keys, 2005-12-09 14:51:24 · CC BY-SA 4.0 · Wikimedia Commons
How this site works
Every figure in a guide is taken from a named source, with the date it was checked. Where a number is an assumption or an example, it says so in the same sentence.
We do not run paid product tests, we do not publish reader reviews, and we do not claim to have handled every product mentioned. Where a claim needs a lab or a long-term test we do not have, the guide says that plainly.
Photographs are free-licence images from Wikimedia Commons or Openverse, credited to the photographer with the licence named. Charts are drawn from the figures printed in the same guide.
This site earns money from advertising and, where disclosed, from affiliate links. That does not change the order of a comparison or the conclusion of a guide.
Some links on this site can earn us a commission. That does not change which product a guide recommends, and it adds nothing to your price. Advertising is not enabled on this site yet. When it is, ads will be labelled and kept visually separate from the guides.
Calculators
Each calculator shows its formula, units and assumptions. Nothing is estimated for you in secret.
Cost per use calculator
Turns a price into a cost per use, so a dear item used often can be compared with a cheap one used rarely.
cost per use = (price + consumables over the whole life) / (uses per week x 52 x years)
Routine cost calculator
How long a bottle lasts and what the routine costs per day, from dose and container size.
days per container = container size (ml) / (dose in ml x applications per day); cost per day = price / days per container
Landed cost calculator
What a cross-border order really costs once shipping, duty and tax are added.
landed cost = (item price + shipping) + duty + tax, where duty = item price x duty rate, and tax = (item price + shipping + duty) x tax rate