The scanner, written out
The ingredient library
What each ingredient actually does, who it suits, and what not to put it next to. The app's product scanner runs this thinking live against your skin profile when you scan a barcode — this is the reference edition.
Most skincare problems are not caused by missing a hero ingredient. They come from too many actives at once, layers that fight each other, or one quiet irritant left in the routine for months. Removing the wrong ingredient usually beats adding a right one.
- Generally safe 16
- Use with care 10
- Usually skip 4
Generally safe
Well tolerated by most skin types. These are the ingredients you can usually add without a settling-in period.
Active
Niacinamide
A vitamin B3 derivative that supports the skin barrier, calms redness, and gradually evens tone. One of the few actives almost everyone tolerates.
Active
Bakuchiol
A plant-derived ingredient often marketed as a gentler retinol alternative. Better tolerated, with a much smaller evidence base.
Hydrator
Hyaluronic Acid
A humectant that holds water in the upper layers of skin. Harmless, popular, and frequently used wrong.
Hydrator
Glycerin
The most reliable humectant in skincare, in almost every moisturiser you have ever used, and cheap enough that nobody markets it.
Barrier
Ceramides
Lipids your skin barrier is already made of. The right answer when skin is tight, flaky, stinging, or over-exfoliated.
Exfoliant
Mandelic Acid
The largest common AHA and the gentlest. A good option for sensitive skin and for deeper skin tones prone to post-inflammatory marks.
Active
Azelaic Acid
An unusually versatile active that handles redness, spots and dark marks at once, and is gentle enough for most sensitive skin.
Emollient
Squalane
A lightweight, stable oil that mimics something your skin already produces. Rarely causes breakouts and suits nearly everyone.
Barrier
Panthenol
A soothing humectant that helps calm irritated, over-treated skin. Common in barrier repair creams and after-sun products.
Barrier
Centella Asiatica
The "cica" of Korean skincare. A soothing botanical with reasonable evidence for calming redness and supporting barrier recovery.
Sunscreen filter
Zinc Oxide
A mineral UV filter with genuine broad-spectrum coverage. The default recommendation for sensitive and reactive skin.
Emollient
Dimethicone
A silicone that smooths skin, reduces water loss, and takes far more criticism than the evidence justifies.
Brightening
Tranexamic Acid
A gentle, well-tolerated brightening agent with growing evidence for stubborn pigmentation, including melasma.
Hydrator
Urea
A humectant at low strengths and a keratolytic at high ones. Excellent for genuinely dry, rough or thickened skin.
Active
Peptides
Short chains of amino acids marketed as collagen signals. Well tolerated, plausible mechanism, modest and inconsistent real-world evidence.
Antioxidant
Green Tea Extract
A well-tolerated antioxidant botanical with anti-inflammatory properties. A good supporting ingredient, not a headline one.
Use with care
Effective, but with a real irritation or adjustment cost. Introduce one at a time and give each a few weeks before judging it.
Active
Retinol
The best-evidenced over-the-counter anti-ageing and acne active, and also the one most likely to make your skin worse before it gets better.
Antioxidant
Vitamin C
A morning antioxidant that brightens tone over time and boosts what sunscreen is already doing. Notoriously unstable in its pure form.
Exfoliant
Salicylic Acid
An oil-soluble exfoliant that gets inside pores. The standard choice for blackheads and congestion, and easy to overdo.
Exfoliant
Glycolic Acid
The smallest AHA, so the most penetrating and the most irritating. Strong results on texture and tone if your skin can take it.
Exfoliant
Lactic Acid
A larger, gentler AHA that exfoliates and hydrates at the same time. The sensible first acid for dry or nervous skin.
Active
Benzoyl Peroxide
The most effective over-the-counter acne ingredient, and the one most likely to dry you out and bleach your towels.
Active
Adapalene
A third-generation retinoid available without prescription in many countries. Stronger evidence for acne than retinol, and more stable.
Preservative
Phenoxyethanol
A widely used preservative that keeps products from growing bacteria. Safe at regulated levels, mildly irritating for a small minority.
Active
Tea Tree Oil
A botanical with real antibacterial activity against acne, and real sensitising potential at the strengths people use undiluted.
Brightening
Kojic Acid
A fungal-derived brightening agent that interferes with pigment production. Effective on dark marks, and a known sensitiser for some.
Usually skip
Commonly irritating in leave-on products, or offering nothing your skin needs. The first things to remove when troubleshooting.
Fragrance
Fragrance
The most common cause of cosmetic contact allergy and irritation, and the ingredient that most often turns a "gentle" product into a problem.
Surfactant
Denatured Alcohol
A volatile alcohol used to make products feel light and dry fast. High in the ingredient list, it is a common cause of dryness and irritation.
Surfactant
Sodium Lauryl Sulfate
A strong cleansing agent that foams well and strips well. Fine in a shampoo, a poor choice for a facial cleanser.
Emollient
Coconut Oil
Excellent on the body, a common trigger for facial breakouts. Highly comedogenic for many people despite its natural-beauty reputation.
Scan a product before you buy it
Free to start. Scan once, read the six-score breakdown, track what improves.
Free download on iOS and Android.
