Every skincare product sold in the EU, US, and most of the world must list its ingredients in INCI format — International Nomenclature of Cosmetic Ingredients. Once you understand how this system works, you can evaluate any product in under a minute.
The Golden Rule: Order by Concentration
INCI lists are always sorted from highest to lowest concentration. The first ingredient makes up the largest percentage by weight; the last makes up the least. Water (Aqua) is usually first in most serums and creams — it's the solvent and often comprises 60–80% of the formula. If a 'hero ingredient' appears near the very end of the list, its actual concentration is tiny (often under 1%).
The 1% Threshold
Manufacturers are only required to list ingredients above 1% in descending order. Ingredients below 1% can be listed in any order after the main ingredients. This threshold is important: preservatives, fragrances, and certain actives often appear below 1% but can still be effective — or problematic. A long ingredient list doesn't mean a bad product; a short one doesn't mean a simple formula.
Common INCI Names Decoded
- Aqua / Water — the solvent base; usually first
- Glycerin — humectant, retains moisture; very common and safe
- Niacinamide — vitamin B3; brightening, barrier support
- Tocopherol — vitamin E; antioxidant
- Retinol — vitamin A; anti-aging active
- Ascorbic Acid — pure vitamin C
- Sodium Hyaluronate — salt form of hyaluronic acid; hydration
- Cetearyl Alcohol — a fatty alcohol (not drying like ethanol); emollient
- Phenoxyethanol — a common preservative
- Fragrance / Parfum — a blend of scent compounds, often undisclosed
Reading for Potential Irritants
Fragrance (listed as Parfum or Fragrance) is the most common cause of allergic contact dermatitis. It can hide dozens of undisclosed chemicals. Alcohol Denat. (denatured ethanol) in the top half of a list dries out skin; lower down it's less concerning as a penetration enhancer. Essential oils are also potential sensitizers — they appear under their botanical Latin names (e.g., Lavandula Angustifolia Oil, Citrus Limon Peel Oil). If you have reactive skin, check for these and patch test.
Marketing Ingredients vs. Functional Ingredients
Many products feature ingredients heavily in their marketing but list them at the very end — below preservatives. At those concentrations, they contribute texture and marketing value, not clinical results. True active products (retinoids, vitamin C, AHA/BHA) list their actives within the first third of the ingredient list, typically at 0.1–20% depending on the ingredient. If a product claims to be a retinol serum but retinol is listed after the preservatives, question the claim.
How to Use This Knowledge
When evaluating a new product: find your target actives and check their position in the list. Check the first five ingredients — they form the majority of the formula and define the product's character. Scan for potential irritants (fragrance, alcohol denat., essential oils) if you have sensitive skin. Use our Ingredient Analyzer to instantly decode any INCI list — paste it in and get a safety score, key actives, and flagged ingredients for your skin type.