How can we define and mesure skincare's efficacy?


In the absence of an objective measuring tool, consumers have the right to question the efficacy of the sometimes high-priced cosmetic skincare products they buy.

Although it is difficult to quantitatively assess how “amazing” or “beautifying” a cream is, we ought to know how effective the hydrating, regenerating, softening and any other claimed effects are, and indeed whether such effects even exist at all. 

While brands often suffer at the hands of regulations which limit claims, even if they are true, to avoid confusion with the medical industry, they are sometimes guilty of overmarketing to maximise profit. With short-term financial gain as their sole objective, such brands have no ethics whatsoever, and their true purpose is not to improve customers’ skin.

They end up talking nonsense, which is difficult to measure.

 The brands that can avoid seeking short-term gains and simply try to offer the best possible products cannot generally finance research to objectively measure the results. These studies are very expensive and can be biochemical (efficacy for the skin on a molecular level) and/or statistical (double-blind study to assess efficacy on a sizeable group, i.e. several thousand participants).

 So efficacy measured quantitatively is a no go.

As a result, we have to rely on a qualitative approach and common sense instead. This simple formula, based on four variables, embodies this idea:

Skincare efficacy
quality of formulation
quality of ingredients
quantity of active ingredients
manufacturing processes


1. Quality of the formulation

Both the fruit of science and experience, it is obviously a crucial part of the end result. An effective formula must include all the ingredients required for the desired effect (hydrating, anti-ageing, cleansing, etc.). It also has to strike a balance between the components as some combinations have no effect, some have positive ones and others negative.

Without going into the sensory aspect (texture and smell) at this stage, the formulator – previously known as the apothecary – must ensure that the result will be functionally useable and stable without any undesirable effects. In Europe, the result must be checked by a toxicologist before being put on the market (to avoid potential allergies and side effects, to check the development of bacterial contamination, etc.).

The principles of aromatherapy and botany, light or sometimes heavy chemistry: the methods used vary according to the brand and how industrialised they are.

2. Quality of the ingredients

Only the quality of the natural ingredients can be studied. How do you assess the “quality” of a synthetic molecule made in a factory? Do we really know what long-term impact it will have on the human body?

The efficacy of a single plant on the skin can vary dramatically, but its name in the formula and on the INCI list displayed on the packaging will be the same. Like a fruit or vegetable, its benefits for the body change completely depending on a variety of factors including the quality of the seed, its potential exposure to plant protection products and pollution, the soil that nourishes it, how much sunlight it receives and how much water it absorbs.

As such, the first reassuring feature to look out for is organic certification: it guarantees that the plant has not been exposed to pesticides and herbicides which weaken it.

There is a second way to evaluate the quality of vegetable oils in particular: were they cold pressed (like high quality olive oil used in cooking) or refined (which weakens the molecular structure and removes some of the vitamins and active ingredients)? We have a whole article on this important subject.

It is worth noting that, although brands are increasingly identifying their organic ingredients as such, they are unfortunately not specifying what oil extraction processes they use.

3. Quantity of active ingredients 

Although conspicuously absent from conventional cosmetics marketing, it is vital information. Which part of the formula really acts on the skin?

As a comparison, conventional cosmetics manufactured in factories contain around 5% active ingredients in their formulas. The rest is a combination of excipient (texture, often petrochemical), fragrances (often synthetic), dyes (often synthetic) and preservatives (always synthetic).

Creams and balms made using artisanal processes contain between 30% and 99.5% active ingredients. The majority of the product is therefore not an excipient which does nothing for the skin, but a vegetable oil, a natural active ingredient which also provides the texture. If possible, water (which has no effect) is replaced by floral water (an active ingredient) or minimised.

4. Manufacturing processes

Another key feature missing from conventional cosmetics marketing, the manufacturing process can completely change the efficacy of a product. If the ingredients are mishandled (heated, transported or mixed too much), they will be stripped of their vitamins and all their beneficial effects. As in the food industry, if you have an outstanding recipe that uses delicious ingredients but grind everything up or heat it too much, then the end result won’t look any good (hence the temptation to add colourings) or taste nice (temptation to add artificial aromas), and it won’t be good for your health either (but it’ll be too late to do anything about it).


At this stage, few brands can boast about genuine efficacy, because their priorities are not these four variables, but rather:

1. The production cost of the formula

This is the number 1 criteria for conventional cosmetics: how to reduce the cost as much as possible, even by a fraction of a penny, because, once multiplied millions of times, it has a real impact on the result.

Taken to the extreme, we end up with products made almost entirely of water or chemical ingredients often derived from oil, produced in factories for an unbeatable price, yet they are ineffective.

2. The sensory experience

Taking advantage of consumers’ natural weakness (pleasing products), companies are engaged in a fierce battle to find the most pleasing texture and the odour that will appeal to the largest number of people.

Here again, to control the result, synthetic ingredients and industrial manufacturing tend to be used rather than plants, as live ingredients are more difficult to control.

Another absurd result: products that feel silky, are quickly absorbed by the skin and smell nice, yet are ineffective.


Consumers must think about these four variables when choosing their cosmetics.

There are apps available to help, for example, Yuka gives you an idea of the quality of the formulation (although strangely it downgrades formulas containing essential oils). As for the rest, the only solution is to do your research, learn to read between the lines and protect yourself against overmarketing. 

That’s the price you have to pay to properly look after your skin... and your wallet.