WO2022268755A1

WO2022268755A1 - Use of a cosmetic composition for preventing and/or treating cutaneous blackheads

Info

Publication number: WO2022268755A1
Application number: PCT/EP2022/066791
Authority: WO
Inventors: Julia PUECH; Nelly Billoni; Potter ANNE
Original assignee: L'oreal
Priority date: 2021-06-25
Filing date: 2022-06-21
Publication date: 2022-12-29
Also published as: FR3124383A1

Abstract

Use of a cosmetic composition for preventing and/or treating cutaneous blackheads The present invention relates to the use of at least one C18 fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads. It additionally targets a corresponding cosmetic method.

Description

Title: Use of a cosmetic composition for preventing and/or treating cutaneous blackheads

Technical field

The present invention relates to the field of cosmetic products, more particularly intended for the prevention and/or treatment of cutaneous blackheads.

It also relates to a cosmetic method, in particular a non-therapeutic method, comprising the application, to the skin to be treated, of a composition containing at least one active principle in accordance with the invention.

Prior art

Cutaneous blackheads, in particular on the face, concern all skin typologies. Due to their black, indeed even brown, color, they are highly visible, all the more so on lightly pigmented skin, and, as such, are generally regarded as unattractive and thus undesirable.

To date, it is accepted that the cutaneous blackhead results from the process of comedogenesis which affects pilosebaceous units of sebaceous follicle type, which are distributed predominantly on the face. From a clinical perspective, a cutaneous blackhead is an open comedo (noninflammatory lesion) characterized by distension of the hair canal, sebum retention and excessive comification of the pilosebaceous duct. Hypercornification results in sebum retention and in the accumulation of cell debris.

Cutaneous blackheads and comedones are different from keratin and keratotic plugs. Keratin and keratotic plugs are clusters of corneocytes, in particular clusters of proteins. They are colourless, while blackheads are, as their name suggests, black or dark brown. As such, while keratin plugs may be present in blackheads, they are not responsible for the black or brown colour of the comedones.

Solutions against keratin and keratotic plugs exist in the art and mainly offer a keratolytic action which helps detach and eliminate keratin from the skin. These compositions eliminate dead skin, therefore tackling the superficial layers that surround the blackhead, but do not act directly on the comedones or blackheads.

Examples of such compositions are provided in JP 2018/021084 which relates to a liquid cosmetic cleansing composition in the form of an emulsion for extracting the proteins which adhere to the skin. Mention may also be made of US 2012/073591 which describes a method for cleansing the skin by removing solid impurities such as keratotic plugs comprising several steps of massaging the skin with different compositions.

Solutions are also already available for treating blackheads. These solutions generally target accumulation of cell debris and sebum retention by an action of desquamation of the surface of the open comedo.

Some of these solutions consist of physical methods based on the use, for example, of comedo suction device, of comedo extractor or of self-adhesive patches to be removed. For obvious reasons, these methods have an aggressive nature with regard to the skin, are not painless and are capable of generating unattractive skin irritation or red marks.

Other solutions are based more particularly on the treatment of the blackheads with an active principle capable of detrimentally affecting them and/or eliminating them, in particular by acting on their coloration. By way of illustration of these active principles, mention may in particular be made of antioxidants, such as, for example, glutathione (GSH), ascorbic acid (vitamin C) or cysteine described in the patent FR 3 044 905 Bl. However, a number of these active principles have the drawback of detrimentally affecting the organoleptic properties of the composition comprising them, in particular the odor and/or the color of the composition, over time. Active principles capable of dissolving constituent lipids of blackheads, such as alkyl lactates, described in the patent US 4 540 567, or else neutralized fatty acids, such as described in the patent application EP 3 150 187, have also been provided.

The present invention results more particularly from the characterization by the inventors of novel active principles which are particularly effective with regard to blackheads and which advantageously prove to be devoid of the abovementioned disadvantages.

Summary of the invention

Thus, according to a first aspect, the present invention relates to the cosmetic use of at least one Ci₈ fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads. Thus, the cosmetic use of at least one Cis fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures proves to be very particularly effective in preventing the appearance of cutaneous blackheads and/or removing cutaneous comedones and blackheads. According to a specific alternative form, isostearic acid and/or oleyl alcohol is/are employed in combination with at least one fatty acid chosen from oleic, linolenic, linoleic, behenic, arachidonic and stearic acid and in particular with at least oleic acid.

As emerges from the examples which appear below, the inventors have, contrary to all expectations, found that isostearic acid and oleyl alcohol prove to be capable of dissolving lipid substances constituting cutaneous comedones and blackheads and thus are shown to be particularly effective in preventing the appearance of blackheads and/or removing these blackheads.

According to another of its aspects, the present invention relates to a cosmetic method for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads, comprising the application, to the skin to be treated, of at least one Cis fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures.

In particular, the cosmetic method in accordance with the invention is of use in preventing the appearance of cutaneous blackheads and/or removing cutaneous comedones and blackheads.

The cosmetic uses and methods considered according to the invention are nontherapeutic.

In particular, the uses and methods considered herein for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads are exclusively cosmetic. The present application does not imply that at least one Cis fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures could be used for therapeutic purposes. In particular, the uses and methods of the invention do not require an expertise or prescription from a medical professional, and may be implemented by any individual wishing to prevent or eliminate inaesthetic imperfections such as blackheads. Again, this is a clear indication that the uses and methods of the invention are nontherapeutic.

The term "the skin" is understood to denote, within the meaning of the present invention, all of the skin of the body, excluding the scalp and the mucous membranes. Preferably, the skin is the skin of the face and/or of the body, in particular of the face and/or of the hands, preferably of the face, and more particularly of the forehead and/or of the alae of the nose and/or of the chin. According to a first alternative form, the skin is greasy and/or glistening skin, in particular skin exhibiting excessive secretion and excretion of sebum. According to this alternative form, the skin is in particular greasy and/or glistening skin, especially of phototype 1, 2, 3 or 4, in particular greasy and/or glistening skin of the face and/or of the hands, more particularly greasy and/or glistening skin of the forehead and/or of the alae of the nose and/or of the chin.

According to a second alternative form, the skin is nonacneic skin, namely healthy skin devoid of the clinical manifestations of acne, namely acne lesions, such as the presence of numerous acne pimples. This is because the blackheads constitute cutaneous imperfections of the skin, distinct from ailments of the skin, such as acne. In particular, the blackhead is not an inflammatory lesion of the skin, in contrast to the lesions characteristic of acne. Furthermore, the regions of the face which are favorable to the development of blackheads, namely more particularly the alae of the nose, precisely do not constitute regions partial to the development of acne.

Detailed description of the invention

Composition suitable for the invention

According to one aspect of the invention, the isostearic acid, the oleyl alcohol or one of their mixtures is employed in the form of a cosmetic composition containing it which is suitable for a topical application.

Advantageously, in this cosmetic use, the cosmetic composition comprises from 0.1% to 20% by weight, preferably from 0.2% to 10% by weight, better still from 0.5% to 5.0% by weight, more preferentially still from 1% to 3% by weight, of isostearic acid and/or of oleyl alcohol, with respect to its total weight.

When isostearic acid and/or oleyl alcohol are employed in the form of a composition, they are formulated therein in a physiologically acceptable medium. Such a medium is considered to be physiologically acceptable when it does not cause any tingling, tautness or discomfort unacceptable for the user.

As specified above, according to a specific alternative form, isostearic acid and/or oleyl alcohol is/are employed with at least one fatty acid chosen from oleic, linolenic, linoleic, behenic, arachidonic and stearic acid and in particular with at least oleic acid. In this alternative embodiment, the use according to the invention can employ isostearic acid and/or oleyl alcohol in combination with at least one of the abovementioned fatty acids in an isostearic acid and/or oleyl alcohol/a fatty acid chosen from oleic, linolenic, linoleic, behenic, arachidonic and stearic acid and their mixtures ratio by weight varying from 10/90 to 90/10, 80/20 to 20/80, 40/60 to 60/40 or also 50/50.

According to a specific alternative form, a composition suitable for the invention contains at least isostearic acid and oleic acid in particular in an isostearic acid/oleic acid ratio by weight varying from 10/90 to 90/10, 80/20 to 20/80, 40/60 to 60/40 or also 50/50.

According to another specific alternative form, a composition suitable for the invention contains at least oleyl alcohol and oleic acid in particular in an oleyl alcohol/oleic acid ratio by weight varying from 10/90 to 90/10, 80/20 to 20/80, 40/60 to 60/40 or also 50/50. According to another specific alternative form, a composition suitable for the invention contains at least isostearic acid, oleic acid and oleyl alcohol in particular in an isostearic acid + oleyl alcohol/oleic acid ratio by weight varying from 10/90 to 90/10, 80/20 to 20/80, 40/60 to 60/40 or also 50/50.

A composition suitable for the invention can be provided in any formulation form normally used in the cosmetics field.

It can in particular be in the form of an aqueous or aqueous/alcoholic solution, which is optionally gelled, of a dispersion of the lotion type, which is optionally a two-phase lotion, of an oil-in-water or water-in-oil or multiple emulsion, of an aqueous gel, of a dispersion of oils in an aqueous phase, in particular by means of spherules, it being possible for these spherules to be polymer particles or, better still, lipid vesicles of ionic and/or non-ionic type, or else in the form of a powder, of a serum, of a paste or of a flexible rod or also of a stick. It can be of solid, pasty or more or less fluid liquid consistency.

Thus, the composition can comprise any constituent normally employed in the topical application and administration envisaged.

Mention may in particular be made of water, solvents, compounds forming a fatty phase which is liquid at ambient temperature, for example oils of mineral, animal and/or vegetable origin, waxes, in particular, pigments, fillers, surfactants, thickeners, gelling agents, preservatives and their mixtures in all proportions. A composition suitable for the invention can advantageously be provided in the form of an emulsion, in particular obtained by dispersion of an aqueous phase in a fatty phase (W/O) or of a fatty phase in an aqueous phase (O/W), of liquid or semi-liquid consistency of the milk type, or of soft, semi- solid or solid consistency of the cream or gel type, or also of multiple emulsion (W/O/W or O/W/O). These compositions are prepared according to the usual methods.

The composition can advantageously comprise at least one fatty phase which is liquid at ambient temperature and atmospheric pressure.

Such a fatty phase can comprise at least one nonvolatile ether oil having from 10 to 40 carbon atoms and/or at least one nonvolatile monoester oil.

Within the meaning of the present invention, the term "nonvolatile oil" is understood to denote an oil, the vapor pressure of which at ambient temperature and atmospheric pressure is nonzero and less than 10³ mmHg (0.13 Pa).

Mention may in particular be made, as example of ethers having from 10 to 40 carbon atoms, of dicaprylyl ether (CTFA name: Dicaprylyl ether).

Mention may in particular be made, as preferred monoesters, of isononyl isononanoate, oleyl erucate and/or 2-octyldodecyl neopentanoate, preferably isononyl isononanoate.

The amount of fatty phase which is liquid at ambient temperature and atmospheric pressure present in the compositions according to the invention, and taking into account the amounts of isostearic acid, oleyl alcohol and any other fatty acid capable of being combined with these, can range, for example, from 0.01% to 50% by weight and preferably from 0.1% to 30% by weight, with respect to the total weight of the composition.

The emulsions according to the invention can comprise at least one emulsifier chosen from amphoteric, anionic, cationic or nonionic emulsifiers, used alone or as a mixture. Advantageously, the emulsifiers are appropriately chosen according to the emulsion to be obtained (W/O or O/W). The emulsifiers are generally present in the composition in a proportion which can range from 0.3% to 30% by weight and preferably from 0.5% to 20% by weight, with respect to the total weight of the composition.

Mention may be made, for the O/W emulsions, for example, as emulsifiers, of nonionic surfactants, and in particular esters of polyols and of fatty acids having a saturated or unsaturated chain comprising, for example, from 8 to 24 carbon atoms and better still from 12 to 22 carbon atoms, and their oxyalkylenated derivatives, that is to say derivatives comprising oxy ethylene and/or oxypropylene units, for example the esters of glycerol and of C₈-C₂₄ fatty acids, and their oxyalkylenated derivatives; the esters of polyethylene glycol and of C₈-C₂₄ fatty acids, and their oxyalkylenated derivatives; the esters of sorbitol and of C₈-C₂₄ fatty acids, and their oxyalkylenated derivatives; the esters of sugar (sucrose, glucose or alkylglucose) and of C₈-C₂₄ fatty acids, and their oxyalkylenated derivatives; the ethers of fatty alcohols; the ethers of sugar and of C₈-C₂₄ fatty alcohols; and their mixtures in all proportions.

A composition suitable for the invention can additionally comprise at least one silicone elastomer, in particular the products sold under the KSG names by Shin-Etsu, under the Trefil, BY29 or EPSX names by Dow Coming or under the Gransil names by Grant Industries.

A composition suitable for the invention can additionally contain one or more adjuvants commonly used in the cosmetics field, in particular sequestering agents, odor absorbers, UV- screening agents, fragrances, mattifying agents, and abrasive fillers or exfoliating agents, and their mixtures in all proportions.

A composition used according to the invention can advantageously comprise at least one additional active principle. The additional active principles may be selected from those commonly employed in the art of cosmetic formulation.

The inclusion of one or more additional active principles does not confer any therapeutic properties to the composition. As such, the uses and methods of the invention remain cosmetic and nontherapeutic even if one or more additional active principles are included in the composition.

The expression "additional active principle" is understood to mean, in the context of the present invention, a compound which has, by itself, that is to say not requiring the intervention of an external agent in order to activate it, a biological activity which can in particular be:

- a desquamating activity (which makes possible the opening of the comedones), and/or

- an antimicrobial activity (in particular with regard to P. acnes ), and/or

- a soothing or anti-irritant activity, and/or

- a sebum-regulating or anti- seborrheic activity, and/or

- an astringent activity, and/or - an activity intended to combat and/or prevent the signs of aging, in particular chronobiological aging, for example wrinkles and fine lines.

The additional active principle which can be used in the compositions of the invention is preferentially chosen from agents which dissolve supplementary lipid compounds, desquamating agents, soothing agents, anti-irritant agents, sebum-regulating or anti- seborrheic agents, astringent agents and their mixtures in all proportions.

According to a specific alternative form, this additional agent is at least oleic acid.

It can also be at least one active principle for caring for greasy skin.

The additional active principle for caring for greasy skin used in a composition suitable for the invention can represent from 0.0001% to 20%, preferably from 0.01% to 10% and better still from 0.01% to 5% by weight, with respect to the total weight of the composition. Mention may in particular be made, as specific example of other additional active principles, of salicylic acid and pro-xylane, in particular extracted from rye seeds.

Moreover, a composition employed according to the invention can advantageously comprise from 5% to 80% by weight and preferably from 35% to 75% by weight of water, with respect to the total weight of said composition.

The pH of said composition is advantageously less than or equal to 8, preferably ranging from 4 to 7, limits included, better still ranging from 4.5 to 6.5, limits included.

A composition suitable for the invention can additionally comprise retinol, otherwise known as vitamin A, preferably all-trans-retinol.

More particularly, a composition suitable for the invention can comprise an amount of retinol ranging from 0.02% to 5.0% by weight, in particular from 0.05% to 3.0% by weight, with respect to the total weight of the composition.

Thus, a composition employed in a use or a method according to the invention can comprise at least one active principle, in particular chosen from oleic acid, salicylic acid, pro-xylane, retinol and their mixtures.

A composition suitable for the invention can additionally comprise at least one polyol, namely an organic molecule comprising at least two free hydroxyl groups, in particular chosen from ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butylene glycol, isoprene glycol, 1,2-pentylene glycol, hexylene glycol, caprylyl glycol, dipropylene glycol, glycerol, pentaerythritol, trimethylolpropane, polyglycerols, polyethylene glycols and their mixtures. A composition suitable for the invention can additionally comprise at least one gelling agent, in particular a hydrophilic gelling agent, namely a compound capable of gelling the aqueous phase of the compositions suitable for the invention. Mention may be made, as examples of hydrophilic gelling agents, of the polymers and copolymers of 2-acrylamido-2- methylpropanesulfonic acid, which are crosslinked and/or neutralized, polysaccharides and their mixtures.

A composition suitable for the invention can also comprise at least one derivative of polyethylene glycol and of mono-, di- and triglycerides of an acid comprising at least one alkyl chain ranging from Ce to C_½, and having at least two ethylene oxide groups, in particular chosen from derivatives of polyethylene glycol and of mono-, di- and triglycerides of caprylic acid and of capric acid, for example that comprising 6 ethylene oxide groups (INCI name: PEG-6 caprylic/capric glycerides), sold under the name Softigen 767 by Sasol. It can also comprise at least one colorant chosen, for example, from pigments, pearlescent agents, dyes, effect materials and their mixtures in all proportions. These colorants can be present in a content ranging from 0.01% to 50% by weight and preferably from 0.01% to 30% by weight, with respect to the total weight of the composition.

A composition suitable for the invention can additionally comprise at least one filler, in particular in a content ranging from 0.01% to 50% by weight, preferably ranging from 0.01% to 30% by weight, with respect to the total weight of the composition. These fillers can be inorganic or organic and of any shape, platelet, spherical or oblong, whatever the crystallographic form (for example sheet, cubic, hexagonal, orthorhombic or amorphous). Of course, a person skilled in the art will take care to choose the optional additional compound(s), and/or their amount, in such a way that the advantageous properties of the Cis fatty acid and/or alcohol which are required according to the invention are not, or not substantially, detrimentally affected by the envisaged addition and that the properties of the compositions resulting therefrom are compatible with the topical administration route.

A composition of the invention can advantageously exhibit a firm and compact feel when taken up. It can be thick on application and subsequently be transformed, melt and release freshness.

According to another alternative form, a composition of the invention can advantageously be provided in the form of a more or less wide stick, such as a pencil, for example. A composition can alternatively have the form of a product for caring for or making up the face and/or the body, and be packaged, for example, in the form of cream in ajar or of fluid in a tube or as a pump- action spray.

A composition according to the invention can be manufactured by any known process generally used in the cosmetics field. The ingredients are mixed before they are shaped, in the order and under conditions which are easily determined by a person skilled in the art.

Cosmetic methods

As mentioned above, the present invention relates to a cosmetic method for dissolving all or part of the constituent lipids of cutaneous comedones and blackheads, comprising the application, to the skin, of a cosmetic composition comprising at least isostearic acid and/or oleyl alcohol and, if appropriate, oleic acid.

Such a method proves to be very particularly useful for preventing the appearance of blackheads and/or removing cutaneous comedones and/or blackheads.

The cosmetic method of the invention is carried out by administering, by the topical route, a composition comprising at least isostearic acid and/or oleyl alcohol and, if appropriate, oleic acid, preferably in a physiologically acceptable medium.

The administration consists of the external application to the skin of cosmetic compositions according to the usual techniques for use of these compositions.

By way of illustration, the cosmetic method according to the invention can be carried out by topical application, for example daily, of at least one fatty acid or alcohol in accordance with the invention which can, for example, be formulated in the form of a cream, gel, serum, lotion, emulsion, make-up-removing milk, stick or aftersun composition.

According to one embodiment, the application is repeated, for example, 2 to 3 times daily for one day or more and generally over an extended period of at least 4 weeks, indeed even 4 to 15 weeks, with, if appropriate, one or more periods of interruption.

According to another embodiment, the application is daily (once per day) and generally over an extended period of at least 4 weeks, indeed even 4 to 15 weeks, with, if appropriate, one or more periods of interruption.

According to another embodiment, the composition including at least isostearic acid and/or oleyl alcohol and, if appropriate, oleic acid is applied to skin regions which have been cleansed beforehand, for example using an appropriate soap, and/or freed beforehand from at least one blackhead, for example using an adhesive patch or a mechanical action. Furthermore, treatment combinations with optionally supplementary topical forms, in order to complement or to reinforce the activity of the isostearic acid and/or oleyl alcohol, can be envisaged.

It might be possible to imagine a topical treatment with a composition containing at least isostearic acid and/or oleyl alcohol, combined with a supplementary composition dedicated to a topical application and containing at least one active principle distinct from isostearic acid and/or oleyl alcohol.

According to an alternative embodiment, this distinct active principle is oleic acid.

Thus, the present invention also relates to a cosmetic method for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads, comprising: a) a stage of application, to the skin, of a cosmetic composition comprising at least one Cis fatty acid and/or alcohol chosen from isostearic acid, oleyl alcohol or one of their mixtures; and b) a stage of application, to said skin treated in a), of a composition different from said composition of stage a) and containing at least one active principle distinct from that of the composition a).

Such a composition applied in stage b) can be described as "supplementary composition". Stages a) and b) defined above can be carried out simultaneously or successively.

This supplementary composition, which is different from the composition suitable for the invention, and applicable by the topical route, can in particular be in the form of an emulsified oil-in-water gel, comprising at least one compound chosen from oleic acid or retinol; polyols; hydrophilic gelling agents; derivatives of polyethylene glycol and of mono- , di- and triglycerides of an acid comprising at least one alkyl chain ranging from Ce to C_½, and having at least two ethylene oxide groups; nonvolatile ether oils having from 10 to 40 carbon atoms; and nonvolatile monoester oils.

Throughout the description, including the claims, the expressions "between ... and ...", "of between ... and ..." and "ranging from ... to ..." should be understood as meaning limits included, unless otherwise specified. The examples which follow illustrate the present invention without limiting the scope thereof.

Materials and methods

The solubilizing effectiveness of the compounds tested was evaluated by targeting the dissolution of palmitic acid, which is the fatty acid predominantly present in blackheads, according to the following protocols:

1) By DSC measurement

In order to evaluate the satisfactory solvent potential of a starting material with regard to palmitic acid, DSC measurements were carried out by studying mixtures according to the following ratio by weight: 20% by weight of palmitic acid + 80% by weight of the compound to be tested.

The measurements are carried out on a TA Instruments DSC Q100, in high-pressure stainless steel crucibles of approximately 20 pi with a leaktight seal.

The crucible containing the sample to be characterized is introduced into an oven at ambient temperature and then equilibrated at 10°C. It is subsequently heated to 80°C with a gradient at 5°C/min. An isotherm is applied for 5 min. This first cycle represents the first melting of the palmitic acid. The temperature is then brought down to 10°C with a gradient of 5°C/min. This second cycle marks the recrystallization of the palmitic acid. Finally, the crucible is heated to 80°C with a gradient at 5°C/min. This last cycle represents the second melting of the palmitic acid. The objective of this measurement is to identify if the compound tested is a good solvent for palmitic acid by shifting the melting peak toward a lower temperature in the second melting. The percentage of palmitic acid molten at 32°C (surface temperature of the skin) could thus be determined for each compound tested as solvent.

2) Characterization of the dissolution of palmitic acid by microscopic observation in the presence of palmitic acid + the compound to be tested.

The microscopic observations are carried out between slide and cover slip by means of a Leica DMLB microscope which is used in transmission mode. The preparation of the samples consists in putting 0.0017 g of palmitic acid and then one drop of the compound to be tested on a slide with spacer placed on a heating stage at 32°C during the microscopic observation (at xlO magnification) over a total duration of 24 h. The state of dissolution of the palmitic acid crystals is characterized by microscopic observation (xlO). 3) Characterization of the dissolution of the lipid components of comedones by microscopic observation.

The samples were prepared precisely with the same equipment and methodology considered for the protocol 2), the palmitic acid being replaced with an ex vivo comedo. A detrimental change in the density of the comedo, exposed to contact with the compound to be tested, is indicative of a detrimental change in the integrity of this comedo and thus in the effectiveness of dissolution of the compound tested.

The results obtained for isostearic acid, oleyl alcohol and oleic acid are given in table 1 below.

[Table 1]

As emerges from the above results, isostearic acid and oleyl alcohol show the most significant effectivenesses with regard to the dissolution of constituent lipids of comedones. Brought into contact with each of these two compounds, the comedones lose in density and thus diminish in volume.

Oleic acid, although having a lower effectiveness, also has a dissolving power with regard to the constituent lipids of comedones.

Claims

1. Cosmetic use of at least one Cis fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads.

2. Cosmetic use according to Claim 1, for preventing the appearance of cutaneous blackheads and/or removing cutaneous comedones and/or blackheads.

3. Cosmetic use according to Claim 1 or 2, employing said Cis fatty acid and/or alcohol in combination with at least one fatty acid chosen from oleic, linolenic, linoleic, behenic, arachidonic and stearic acid and in particular with at least oleic acid.

4. Cosmetic use according to any one of the preceding claims, in which said Cis fatty acid and/or alcohol is employed in the form of a cosmetic composition intended for a topical application.

5. Cosmetic use according to the preceding claim, in which said composition contains from 0.1% to 20% by weight, preferably from 0.2% to 10% by weight, better still from 0.5% to 5.0% by weight, more preferentially still from 1% to 3% by weight, of isostearic acid and/or of oleyl alcohol, with respect to its total weight.

6. Cosmetic use according to either one of Claims 4 and 5, in which said cosmetic composition further comprises at least one additional active principle, in particular chosen from oleic acid, salicylic acid, pro-xylane, retinol and their mixtures, and preferably at least oleic acid.

7. Cosmetic method for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads, comprising the application, to the skin to be treated, of at least one Cis fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures.

8. Cosmetic method according to the preceding claim, useful for preventing the appearance of cutaneous blackheads and/or removing cutaneous comedones and/or blackheads.

9. Cosmetic method according to Claim 7 or 8, in which the skin is the skin of the face and/or of the body, in particular of the face and/or of the hands, preferably of the face, and more particularly of the forehead and/or of the alae of the nose and/or of the chin.

10. Cosmetic method for dissolving all or part of the constituent lipids of cutaneous comedones and/or blackheads, comprising: a) a stage of application, to the skin, of a cosmetic composition comprising at least one Ci₈ fatty acid or alcohol chosen from isostearic acid, oleyl alcohol and their mixtures; and b) a stage of application, to said skin treated in a), of a composition different from said composition of stage a) and containing at least one active principle distinct from said fatty acid and/or alcohol.

11. Cosmetic method according to the preceding claim, for preventing the appearance of cutaneous blackheads and/or removing cutaneous comedones and/or blackheads.