How do you demonstrate the effectiveness of your natural cosmetics formulas?

efficacité des formules cosmétiques naturelles

What is an effective cosmetic product?

An effective cosmetic is a product whose effects on the superficial parts of the body vary in a convincing way, i.e. it achieves an expected result. For example, after applying a moisturizing cream, the expected efficacy is an improvement in hydration. And we want the result to be less dry skin and less tightness.

The expected efficacy of natural cosmetic formulas must remain consistent with its regulatory definition (according to European cosmetics regulation (EC) n°1223/2009):

“Cosmetic product means any substance or mixture intended to be placed in contact with the superficial parts of the human body (epidermis, hair and capillary systems, nails, lips and external genitalia) or with the teeth and oral mucous membranes, with a view, exclusively or mainly, to cleaning them, perfuming them, modifying their appearance, protecting them, maintaining them in good condition or correcting body odors. “

It is therefore important to remain within this definition and not to encroach on claims that would be specific to drugs (“Acne treatment”, “Healing”) or medical devices (permanent make-up, decongestant nasal spray, intimate lubricant). Whether it’s a claim such as: anti-wrinkle, moisturizing, slimming, waterproof… The claimed effect must be demonstrated and justified using a judicious and relevant test protocol that corresponds to the final use of the cosmetic product.

Independent laboratories carry out these tests, ensuring objectivity and reliability in the results they produce. Test reports form an integral part of the Product Information File (PIF), which is made available to the authorities to guarantee the regulatory conformity of the marketed product.


How can the efficacy of natural cosmetic formulas be demonstrated?

There is no standardized method for supporting a claim. However, the ARPP (Autorité de Régulation Professionnelle de la Publicité) recommends that “All claims must be truthful, clear, fair, objective and not misleading”. It is therefore up to the marketer to define (in consultation with test laboratories) the most appropriate protocol for providing tangible evidence in line with the principles of this recommendation.

To do this, he can draw on a range of available, tried-and-tested methods, as well as on the creativity of test laboratories. These laboratories are constantly working to develop methods in line with the latest consumer expectations in terms of product efficacy.


     1) In vitro” testing

In vitro means “in glass” in Latin, referring to the glass of test tubes. These are tests carried out in the laboratory to observe phenomena in an artificial environment. For example: cells, outside their natural environment. These tests are essential in the early stages of product development. They can also be used to demonstrate the truth of a claim. However, they cannot be relied on 100%, as these models (usually single-cell models) do not take into account the multifactorial dimension of living organisms. Consequently, conclusions observed in vitro often await confirmation in vivo.


     2) In vivo” tests

In vivo means “in the living” in Latin. This work is carried out in a whole, living organism. These tests involve volunteers (“panellists”) who may or may not have been trained in the sensory evaluation of products. To assess specific criteria, laboratories have also developed “Ex vivo” protocols. These are based on human samples, such as strands of hair or human skin explants kept alive.


          A. Instrumental tests

These tests use a variety of measuring instruments to quantify an effect precisely and objectively. They are based on classic physical and chemical measurement principles. They are then adapted to measure parameters such as skin hydration or firmness, sebum levels or pigmentation.

For example:

Corneometry measurement actively assesses the hydration level of the surface layers of the epidermis, using the dielectric capacitance method. Capacitance represents the capacity of a component or circuit to receive and store energy in the form of an electrical charge. As water is a good electrical conductor, it is possible to evaluate the moisturizing effectiveness of a cosmetic product on the material that is the epidermis, before and after its application (with follow-up over several hours for claims such as 24-hour hydration), thanks to this method.
Sebumetry is the measurement of sebaceous secretion using a photometric method. A transparent film (glass or plastic) is applied to the area to be assessed (skin, scalp, hair) for a few seconds. A cell then analyzes the transparency of this film. The transmitted light represents the sebum content of the area being measured, enabling results to be expressed in µg of sebum / cm2 of skin.


          B. Use tests

These tests enable us to evaluate a product under normal conditions of use, under medical supervision, usually dermatological, but sometimes ophthalmological. Use tests have a dual purpose: they validate the tolerance and efficacy of a cosmetic product on a panel of several dozen users.

After receiving information on the product and its use, the tester activates the product’s use at home, following normal conditions of use. After a given period, they return to the research laboratory to fill in a questionnaire assessing their feelings about various aspects of the product. The questionnaire comprises around twenty questions. If necessary, observers note physical signs of skin reaction (redness, itching, erythema…) to assess product tolerance.

Questions validated positively by more than 75% of the panel are considered statistically significant. Consequently, they are considered valid to justify the claim.

Example: “My skin is matte after use”. If a minimum of 75% of the panel responded positively, the marketer can put the “mattifying” claim forward on his product.

Use tests can be carried out using panels of non-specific volunteers, or by selecting participants according to criteria such as gender, age, skin, hair or scalp type. In this way, the expected effect can be targeted as effectively as possible.


     3) The effectiveness of natural formulas

The effectiveness of a cosmetic product depends on the base on which the formula is based, as well as the active ingredients.

Whatever the type of cosmetic and whatever its galenic form (cream, gel, powder, paste, balm…), the basic composition of a cosmetic is more or less the same. For:

  • 80% to 90% excipients: basic raw materials (including water). They help to obtain the desired texture, color or scent, and stabilize the formula.
  • 10% to 20% active ingredients.

In conventional cosmetics, excipients mostly come from the petrochemical industry: mineral oils, silicones, synthetic gelling agents… These ingredients offer numerous technical and sometimes economic advantages, but are of limited benefit to the skin.

In contrast, natural and organic cosmetics use natural excipients: vegetable oils, waxes, floral waters, etc. They provide genuine skin care. All these plant materials are active ingredients in themselves. They are beneficial for the skin because they are rich in omegas, polyphenols, isoflavones, anti-oxidants, etc. Vegetable oils, for example, are rich in vitamins and fatty acids, which are very well assimilated by the skin. Since excipients of natural origin can be considered active ingredients in their own right, natural and organic cosmetics will contain a higher quantity of “active” ingredients than conventional cosmetics.

Natural and organic cosmetology is increasingly interested in plants/algae as active ingredients, as they wage a merciless struggle to survive in their environment. They develop a highly sophisticated protection system to resist aggression and ensure the survival of their species. Maintaining hydration levels, neutralizing free radicals, regenerating and healing are just some of the particularly sophisticated vital functions of plant metabolism.

Plants and algae therefore represent a considerable wealth of powerful active ingredients, in perfect affinity with our skin.


The efficacy of promised natural cosmetic formulas is a key factor in the act of purchasing a cosmetic product. For years, conventional cosmetics manufacturers have regarded organic and natural cosmetics as less effective, while vying with each other to present increasingly sophisticated claims.

Natural cosmetics now hold all the cards to take center stage. On the one hand, consumers are looking for a return to basic needs (cleansing, moisturizing, nourishing), and on the other, raw material suppliers are increasingly innovative in expanding their portfolios of natural raw materials.