Le dico des skintellectuelles - CLEAN PLANET - WE ARE CLEAN

The skintellectuals’ dictionary fom C to W

The skintellectual movement first appeared here in France, when the first controversies over certain molecules arose (over parabens, back in 2005). It did so first of all with the setup of specialised blogs, and now podcasts and Instagram accounts (or even TikTok content). There’s now a label for beautystas who demystify the INCI in formulations. Yet again it’s from the English-speaking world, where the trend is much more recent (going back only 2-3 years). That label is skintellectual, a contraction of the words “skin” and “intellectual”. These skincare addicts now have direct access to brands and consumers thanks to social media. They are specialists when it comes to the skin and its various issues, the art of putting together formulations and active ingredients. Skintellectuals have taken control of knowledge, and ultimately of their behaviour as consumers and that of their followers. Here is their lexicon from C to W:

Clean beauty

The term clean beauty refers to a beauty product that is virtuous. It is not limited to a formulation “cleansed” of any controversial ingredients, but encompasses all the aspects that come into play in a product’s design and production. These include the packaging and the whole value chain, ethics and transparency. Every aspect of its life cycle is important: the sourcing of the ingredients, formulation, production with development that’s as sustainable as possible, eco-design of the packaging and its degradability, respect shown to the workers who produce the product, innocuity and non-ecotoxicity of the formulatio


An emulsion is a heterogenous mixture of two liquids which cannot usually be mixed together. In beauty products they comprise an aqueous phase and an oily phase. Thanks to specific processes (agitation or addition of active ingredients called emulsifiers or surfactants to better bind emulsion), they take on a homogenous appearance. In fact, this is a dispersion of one phase in the other in the form of microdroplets. The aqueours phase is made up of water and water-soluble ingredients, and the oily phase of oils and oil-soluble active ingredients. The majority of beauty products are made up of Oil in Water (O/W) emulsions whereby the oily phase is dispersed as droplets in the aqueous phase. This emulsion achieves a fine, non-oily consistency which is easily absorbed by the skin. Some creams are of the Water in Oil (W/O) emulsion type. This brings immediate relief to the driest of skins by supplying them with significant, instantly-accessible nutrition. Some emulsifiers make it possible to yield biomimetic emulsions arranged with a lamellar structure like skin membranes.

Essential oils

Essential oils - CLEAN BEAUTY - WE ARE CLEAN

These plant extracts are yielded via extraction (distillation using water vapour or CO2), or cold pressing in the case of citrus fruit. Essential oils were known about back in 3500 B.C, and used empirically by virtue of their beneficial effects on physical and mental health. Technological advances have made it possible to better pin down the way in which they work through an understanding of their chemotypes (main biochemical components: pinene, limonene, thymol, etc.). There are big differences, for a single plant, according to species, genus and the location where it grows. These days it’s even scientifically possible to get an objective view of essential oils’ exact action and efficacy, through clinical studies or even through observation of the genes expressed after their use. The potency of their action is down to the fact that essential oils enter the bloodstream and reach their target through blood circulation. More than a dozen essentials oils are used in beauty products, by virtue of their soothing, antibacterial, antifungal, astringent, anti-ageing or regenerative properties… Since an essential oil can contain up to 250 molecules, it often has multiple properties and can address both wrinkles and dermatoses.
In aromatherapy and aromachology scents pass through the nasal cavity, which sends an electrical and chemical influx to the olfactory bulb. This in turn is directly linked to the brain’slimbic system : the part concerned with emotion and memory. The limbic system then orders the production of immune system substances and hormones. It has now been scientifically proven that you can restore your emotional balance by breathing in the essential oils that best suit your needs on a daily basis.

Good to know: pure essential oils must not come into contact with the skin. Some of them, like savory, cinnamon, thymol thyme and clove, are dermocaustic and therefore irritant.


Beauty product formulation is a matter of complex knowhow. Originally it was about combining, in the best way possible, ingredients which were often nigh on incompatible with one another to address a physiological need. Knowledge about the skin, and how it reacts to harsh chemicals, light and oxidation, make it possible to put together the active ingredients and adjuvants (emulsifiers, preservatives, fragrance, etc.) which must be included in its formulation.
Formulation draws on several scientific disciplines: physics, physiochemistry, chemistry, biology and also economic and social science and human sciences… Because it’s no longer enough for the formulation to meet certain prerequisites: innocuity, safety, stability and efficacity (which require a great many tests during and after the formulation process). It must also be pleasant (appealing to the senses) so as to be enticing, and comply with the EU’s stringent regulations. But when it comes to so-called clean beauty products, formulation criteria become even more stringent, including carefully-chosen ingredients which must be as clean as possible, traceable, socially and ecologically acceptable, arrangements for green production and a reduced footprint. This explains why it takes 12 to 18 months to develop a skincare formulation.

Fruit acids (AHA, BHA and PHA)


Alphahydroxy acids are natural sugar acids, which can be extracted from fruit (glycolic acid from sugar cane, malic acid from apples and grapes, citric acid from oranges and lemons, etc. However, those used in beauty products are mostly synthetic. They are the active ingredients that oily, acne-prone and saggy skin like best. Because the main property of AHAs is that of being keratolytic. They have exfoliating powers because they manage to break the bonds between the cells of the stratum corneum. Thus the dead skin cells fall away, leaving the complexion brighter and softer. AHAs also have the power to absorb water and thus affect the skin’s hydration level and elasticity. At higher concentrations (between 8 and 15%) and low pH, they promote the synthesis of collagen and glycosaminoglycans, which make up the matrix of the dermis. However, since they refine the skin, they make it more vulnerable and can cause a stinging sensation, irritation and photosensitivity (to UV rays). Hence some skin types fare better with BHAs (salicylic acid) or PHA (polyhydroxy acids, which are more complex acids) like glucuronolactone, which have larger molecules and are better tolerated.


This is a reaction that takes place between sugar and the collagen and elastin fibres in the dermis. Glucose, which circulates freely in the bloodstream, kind of “caramelises” these proteins, making them harder and less operational. As a result, wrinkles get deepened.

Hyaluronic acid

This complex sugar is a natural component of the epidermis and especially of the extracellular matrix of the dermis. It alone contains 50% of the hyaluronic acid in the whole body. It gets constantly produced and destroyed, with a lifespan of 24 hours, but its quantity diminishes with age (50% of the reserve is used up by the age of 50).
Like a sponge, hyaluronic acid retains up to 1,000 times its weight in water. It is biomimetic, i.e.  able to mimic the body. Originally harvested from cockerel combs, these days it is produced via biotechnology from wheat or beets. In beauty therapy it is injected as a moisturiser and stimulant in fluid form, or as a filler and volumizer if it has a thicker consistency. In beauty products it is used in various molecular weights (or sizes). Hyaluronic acis with high molecular weight fixes water and smooths the skin’s surface. That with low molecular weight, or fragmented hyaluronic acid, gets further inside and stimulates the production of hyaluronic acid in the epidermis. The cells of the epidermis then instruct those of the dermis to produce more collagen. In this way, it puffs the cushion of the dermis back up, plumps the skin back up and pushes wrinkles out from the inside.


There are two kinds of skin inflammation: visible and invisible. Acne, atopic dermatitis (eczema), psoriasis and seborrheic dermatitis are types of dermatosis with inflammatory variants. But there is also a silent type of inflammation which is not immediately visible, called inflamm-ageing (a contraction of the terms “inflammation” and “ageing”), which were first described in the 2000s by Prof. Franceschi. This micro-inflammatory state, which is imperceptible, chronic and “low noise”, is caused by multiple damaging factors related to our lifestyle and environment, which the body cannot handle. The body gets overwhelmed and then develops continuous inflammatory microreactions, meaning regular stimulation of destructive enzymes which eat away at healthy tissue. In addition, this inflammatory reaction increases the production of free radicals, which amplifies the phenomenon. Inflamm-ageing and oxidative stress are mechanisms which fuel one another. They present on the skin in a great many ways: lacklustre reactive skin, sagging, wrinkles, rosacea, age spots… And therefore accelerated ageing.


Obviously, you think of lipids in the skin as triglycerides, which get stored in the adipocytes in the hypodermis to form cellulite and the orange peel look. But lipids are also essential fatty acids, present in the skin in many places. Lipids are among the components of cell membranes. In the stratum corneum, they make up the intercellular cement (ceramides, cholesterol and fatty acids) which forms the skin’s barrier. The sebaceous glands, which are found at the base of hairs, also produce various kinds of lipids. These form part of the makeup of sebum and of the hydrolipidic film that covers the skin and guards it against dehydration and external damaging factors. So lipids, which make up around 2% of skin tissue, are essential to keeping it in balance. In case of dry skin (therefore skin lacking in lipids), favour omega 3 or 6 fatty acids. You should get them both from your diet (oily fish, rapeseed, olive and walnut oils) and from beauty products high in borage, evening primrose and argan oils, squalene and ceramides.



Organic beauty products are certified as such by charters and certifications (here in France, Cosmos, Natrue and Nature & Progrès). For a product to secure one of these certifications, its formulation must meet a schedule of specifications stating the proportion of ingredients which are organic, natural or of natural origin (which varies from certification to certification). It also rules out a certain number of controversial chemicals. The products are inspected by accredited bodies, the best-known of which is Ecocert, to check their conformity. However, no beauty product is 100% organic, unless it’s something like pure shea butter or organic plant-based oil. But the more water a formulation contains, the lower its percentage of organic ingredients will be (since water cannot be certified as organic). Since a beauty product is not a vegetable, its footprint goes beyond the fact that its formulation contains a lot of organic ingredients. That is why organic certifications go beyond certified ingredients and impose a stringent charter spanning production, packaging and ecological footprints.


Giving water to the skin is not the way to hydrate it. The water from the shower does not soak in, and the water that you drink only reaches the skin after having supplied all the vital organs. Water ascends from the dermis (the deep-down layer of skin), which is 70% water, to the epidermis which is 60% water, then the surface layer or stratum corneum, which is only 13% water. Yet this is where hydration affects the skin’s appearance the most. The stratum corneum is a kind of brick wall (made up of corneocytes) whereby water is trapped by sponges, callednatural hydration factors, of which urea is one of the essential components. This wall is mortared with intercellular cement (ceramides) and its surface protected by the hydrolipidic film. Water escapes by ascending through the skin, in a process known as transepidermal water loss. If the cement is not of good quality or if the hydrolipidic film has holes in it, the percentage of water drops to 10% or even 7%, the skin feels tight and becomes lacklustre. This can also be because the water does not manage to make its way up from the deep-down layers. Yet dehydrated skin is not only uncomfortable, but also ages faster. The ingredients used for hydration purposes are glycerine which reduces water loss, hyaluronic acid which traps water, urea which fixes water and sugars (rhamnose and trehalose) which strengthen natural hydration factors.

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