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When you apply a cream, you perform an action that takes just a few seconds. Behind it lies a process that, for a new product, lasts an average of twelve to twenty-four months and involves chemists, toxicologists, analytical laboratories, and a safety assessor. I thought I would describe it from the inside, because it is the work I do every day and because understanding it helps explain why some products cost what they do — and why others promise things they cannot deliver.
It all starts with a problem, not an ingredient
The starting point is never “let's use this active because it's trendy,” but a concrete question: is there a skin concern that the market is addressing poorly? Only then do you look for the molecule.
The selection of active ingredients is based on scientific literature and documentation from raw-material suppliers. This is where the first distinction is made, and it is worth recognizing as consumers too: an active ingredient may have independent published studies or only tests conducted by the manufacturer that sells it. Both have value, but they are not equivalent. A serious company makes the difference clear.
The recommended use concentration, the molecule's stability, and its compatibility with the rest of the formula also matter. An excellent active ingredient in a test tube may be unusable if it degrades on first contact with light or requires a pH that is incompatible with the other ingredients. Vitamin C is the best-known example: extremely powerful and notoriously difficult to stabilize.
Formulation: much more than mixing
A formula is not a sum of ingredients; it is a balance. The formulator has to keep several elements in harmony:
- pH, which must be compatible with the skin's pH and with the activity of the selected ingredients
- The emulsifying system, which keeps the water and oil phases together
- The preservative system, essential for microbiological safety
- Texture and sensory properties, which are not frivolous: an unpleasant product will not be used consistently, and without consistency there are no results
- Delivery, meaning how the active ingredient reaches the layer where it needs to act
There is a great deal of confusion about this last point. The skin barrier exists precisely to prevent substances from passing through: that is its job. A cosmetic acts on the superficial layers of the epidermis, not “deep down” in the literal sense. Formulations can improve an active ingredient's affinity and bioavailability; they cannot turn it into an injectable drug.
Testing: the part nobody talks about
This is the longest and least visible phase, and it includes several very different steps.
Stability
The formula is stored at different temperatures — typically 4°C, room temperature, and 40°C — to check that it does not separate, change color, alter its pH, or lose effectiveness over time. Accelerated tests simulate product aging and are used to establish the expiration date and the PAO, the period of use after opening.
Challenge test
The product is deliberately contaminated with known microbial strains to verify that the preservative system eliminates them. This is the test that makes a cosmetic safe to open and touch with your fingers for months. People who ask for “preservative-free” cosmetics often do not realize that they are asking for a product that could not pass this test.
Compatibility with the container
The formula is tested inside the final packaging because some ingredients interact with plastic or metal. This is also why changing the container means repeating the tests: the container is part of the product.
Dermatological testing
Conducted on volunteers under medical supervision, these tests verify the absence of irritating reactions. This is where the claims “dermatologically tested” and “nickel tested” come from. Be aware of a common misunderstanding: “dermatologically tested” means that the test was carried out, not that the result was excellent. It is a statement about the process, not about its merit.
Efficacy testing
These are the tests that support product claims. They may be instrumental — corneometry for hydration, TEWL measurement for the skin barrier, image analysis for wrinkles and spots — or based on volunteers' self-assessments. Here too, an important distinction is useful: “90% of users perceived more hydrated skin” is a perception-based result, not an instrumental measurement. Both are legitimate, but they say different things.
The dossier nobody sees
Before a cosmetic can be sold in Europe, Regulation (EC) No 1223/2009 requires the creation of the PIF, the Product Information File. This dossier contains the qualitative and quantitative composition, raw-material specifications, test results, stability and microbiological data, and above all the safety report signed by a qualified safety assessor — a professional trained in toxicology, pharmacy, medicine, or chemistry.
The product must then be notified to the European CPNP portal before being placed on the market. Without these steps, it cannot be sold: this is not a company choice; it is the law.
One practical consequence of all this is that in Europe no cosmetic product may be tested on animals, neither the finished product nor its ingredients. This has been prohibited since 2013. When a brand presents “cruelty-free” as a distinctive achievement of its own, it is claiming credit for complying with an obligation that applies to everyone.
What is really changing today
In recent years, innovation has been found less in individual ingredients than in the way they are selected and combined.
Biotechnological active ingredients — obtained through fermentation or plant cell cultures — make it possible to obtain molecules with consistent purity without depending on agricultural yields. Biomimetic peptides replicate sequences recognized by the skin, acting more as signals than as filling substances. And research into the skin microbiome has shifted the focus from disinfection to balance.
The most solid trend, however, is something else: shorter INCI lists. Fewer ingredients, better chosen, at meaningful concentrations. A formula with forty items on the label and all the active ingredients at the end is almost always a marketing formula.
How to read a label without being misled
- Order matters. Ingredients are listed in descending order down to 1%. An active ingredient mentioned on the front but listed after the fragrance is present only in trace amounts.
- Look for the stated concentration. If a brand is proud of its 10% niacinamide, it will say so. If it does not, there is often a reason.
- Distinguish perception from measurement in efficacy data.
- Be wary of therapeutic claims. A cosmetic improves the appearance and comfort of the skin. It does not treat acne, psoriasis, rosacea, or dermatitis: these are medical conditions, and the appropriate reference is a dermatologist.
If you want to explore how individual ingredients work, the cosmetic ingredients guide examines them molecule by molecule.
Why I am telling you this
Understanding the journey that leads to a cosmetic product is not just about justifying its price. It helps you make better choices: recognize when a promise is realistic and when it is not, and stop changing products every three weeks in pursuit of the latest novelty.
The next time you apply a cream, you will know that behind that action lie months of testing, a dossier hundreds of pages long, and the signature of someone who is legally responsible for it.
Elisa Avalle, founder of LeLang Skin Care
