The Skin Formulary
Ingredient guides, routine advice, and the science behind skincare — written for curious, discerning readers.
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The only BHA used in skincare, salicylic acid works inside pores rather than on the surface. Here's what that actually means, who it's for, and how to use it without wrecking your skin barrier.
Recent articles
Niacinamide and salicylic acid are two of the most popular actives for acne-prone skin — and they work remarkably well together. Here's why, how to layer them, and what to watch out for.
Azelaic acid and retinol are two of the most versatile actives in skincare — and they work surprisingly well together. Here's how to combine them safely, who benefits most, and when to be cautious.
The conventional wisdom says never. The evidence says it depends on the form, the timing, and your skin. Here’s what actually matters.
AHAs exfoliate the surface. BHAs clear out pores. Using both sounds like a good idea — and it can be, if you understand the ground rules.
The myth that niacinamide and vitamin C cancel each other out has been circulating for over a decade. The science disagrees — and the answer is more useful than the debate.
Both brands made affordable skincare credible. But they have different philosophies, different strengths, and different ideal customers. Here's an honest comparison based on the formulas.
The internet will tell you they cancel each other out. The science says something more nuanced, and more useful.
Not all acne is the same, and not all acne ingredients work the same way. Here's what the evidence says, and how to build a routine that actually addresses the cause.
L-ascorbic acid vs. ascorbyl glucoside vs. sodium ascorbyl phosphate: the Vitamin C family is vast and confusing. Here's how to decode the labels.
Most people start with too much. Four well-chosen products will do more for your skin than a ten-step routine you don't understand.
Pore-minimising, oil-controlling, barrier-repairing, brightening: niacinamide is one ingredient that genuinely does it all. But is 10% always better than 5%?
The advice online ranges from alarmist to dangerously vague. We went through the safety data for every ingredient in our database so you don't have to.
Tretinoin, retinaldehyde, retinol, retinyl palmitate: the vitamin A spectrum is vast. Understanding the conversion chain changes how you shop for anti-ageing.
Fragrance is the leading cause of cosmetic contact dermatitis. Here's what it actually is, why it's in so many products, and how to avoid it if your skin needs you to.
Mixing actives is where routines go wrong. A simple pH and function framework cuts through the confusion, and it actually works.
Both exfoliate. Both brighten. But glycolic acid and lactic acid work very differently on skin, and choosing the wrong one is one of the most common mistakes in an active routine.
If your skin is persistently dry, reactive, or sensitised, ceramides might be the one ingredient class you are systematically overlooking.