They are seeking simple, natural products, and demand greater transparency regarding the composition of their cosmetics, especially concerning worries over certain substances (silicones, aluminium, parabens, phtalates, etc.). They are even showing increasing concern regarding the methods of production used (Are they energy-efficient? Water-efficient?) and the raw materials employed (Where are they from? What is their carbon footprint? Are they produced by fair trade sources? Is the sourcing sustainable?). At the same time, consumers do not wish to compromise on the ‘pleasure’ factor, or effectiveness; quite the opposite. Natural products must be able to provide identical performance to those of traditional synthetic components, which fosters a positive impetus in favour of innovation for natural formulas and a strong consumer demand. Expertise in natural formulation has enabled Alban Muller to develop an innovative ‘sensorial’ ingredient, as a natural alternative to synthetic silicones: Lipolami. Obtained from milk thistle, an original plant for cosmetics, Lipolami takes the form of a dry soft-touch, fluid oil. It can be used to provide finished products with a smooth, silky and nonsticky texture with no silicones. It offers a feeling of extreme softness when applied. Lipolami is also an active ingredient source of omega-6 fatty acids that contribute to reinforce the skin barrier. It offers exceptional dispersing and solubilising properties which make it an interesting ingredient in sun care, make-up, perfumery, etc. Lipolami (now referred to as ‘the natural silicone alternative’) is obtained by transesterifying triglycerides from milk thistle fatty acids. This process produces monoesters, which give the oil its dermocosmetic properties. These natural fatty acid esters are very fluid and are dry to the touch, which means they can be used to formulate lighter textures than vegetable oils while retaining their dermocosmetic properties.
Tests
Sensorial test for emulsions
A comparative blind study between five separate textures was carried out to evaluate the sensorial qualities obtained by adding 5% of the following to a basic formula:
• Sweet almond oil (used as the reference).
• The natural silicone alternative.
• Dimethicone (silicone).
• Cyclopentasiloxane/Cyclohexasiloxane (silicone).
• Dicaprylyl carbonate (ester).
Method
Five experienced volunteers gave marks for four textures according to five parameters: how easy it is to spread it, soaping, sticky sensation, smoothness and softness. An assessment note is given for each parameter on a scale ranging from 0 to 10. The texture of sweet almond oil was used as the control witness and was given a mark out of five for all parameters.
Results
An average of all notes of the five volunteers is made for each parameter. The results are represented in Figure 1. The formula with the natural silicone alternative gives the best average on most parameters. Examining each parameter shows that the natural silicone alternative can be used to formulate natural, melting, smooth and non-sticky products. It provides a feeling of extreme softness when applied, and reduces the soaping effect.
Use in foaming products
When used in foaming products, the natural silicone alternative decreases the drying effect of the surfactants, which manifests as a feeling of comfort when applied to the skin as well as, after shampoo, hair is supple, easy to untangle and easy to style. Up to 1.5% (even more depending on formulas), natural silicone alternative can be added directly to foaming products (without using solubiliser) and without affecting their transparency or their foaming power.
Reinforcement of skin barrier function
The natural silicone alternative has the same proportions of fatty acids as the oil from which it is made. It thus contains over 50% linoleic acid, an essential unsaturated fatty acid, the precursor of the omega-6 family. This fatty acid forms part of the natural composition of the skin barrier. Adding extra linoleic acid reinforces and thus improves the preservation of the skin’s ideal hydration level. ‘Essential’ fatty acid means ‘nonmetabolisable by the organism’, i.e. it must come from an outside source. It was discovered that linoleic acid was essential in the 1960s, based on a finding that deficiencies in linoleic acid resulted, among other pathological symptoms, in a heightened loss of moisture from the skin and excessive keratinisation of the epidermis. Linoleic acid is present in the complex lipids of the epidermis, particularly linked to ceramides, which are essential for the proper functioning of the skin barrier. It thus contributes to keeping the skin supple and hydrated. The esters typically used in formulation come from saturated fatty acids, mostly from coprah and palm oil: caprylic, lauric, myristic, palmitic and stearic acids. These esters are not essential fatty acids and do not confer this benefit.
Technical benefits in formulas
The natural silicone alternative can also fulfil several roles as part of cosmetic formulas. Indeed it combines its sensory appeal with extremely interesting technical benefits as for example stability and fineness of emulsions, sunscreen dispersion and solubilisation.
Stability and fineness of emulsions
Observation revealed that the emulsion obtained with the natural silicone alternative is noticeably finer and more homogeneous than the one formulated with sweet almond oil. It is therefore much more liable to be stable and is light and refined to the touch (Fig. 2).
Disperses and solubilises sunscreens
Good solubility of powder form sunscreens helps to get an effective SPF. The solubilisation of two commonly-used sunscreens (benzophenone-3 and butyl methoxydibenzoylmethane) was tested using control solubilisers (C12-15 alkyl benzoate and coco-caprylate) and using the natural silicone alternative.
Method
Sunscreens were solubilised at 20°C when magnetic agitation. 0.1 g (1%) sunscreen was added to 10 g of each solubiliser tested. The mixture is agitated until complete solubilisation is achieved. It must be transparent. If the mixture is clear, the process is repeated, adding 0.1 g sun filter every time, until the mixture becomes cloudy. This is the sign that the mixture has exceeded its solubility threshold. The final clear mixture is stored for one week at room temperature to monitor any potential recrystallisations after 24 hours, 48 hours and 1 week.
Results
The results obtained with the natural silicone alternative are very close to those obtained with conventional solubilisers and solubility of sunscreens in the natural silicone alternative is greater than 10%. Liquid sunscreens such as octylmethoxycinnamate must be perfectly miscible with the solvents used, as it is the case for the natural silicone alternative. Finally, mineral sunscreens need to be properly dispersed in the finished product in order to form a homogeneous screen, to optimise the SPF. We compared the dispersion of titanium oxide treated with aluminium stearate in C12-15 alkyle benzoate and in the natural silicone alternative. Observation under a microscope showed an identical dispersion.
Conclusion
Lipolami Milk Thistle is therefore a natural alternative to chemical solubilisers because it effectively solubilises and disperses sunscreens, both chemical and mineral. This means that sun protection products can be more natural (Fig. 3). Also Lipolami also can efficiently disperse pigments and minerals for make-up products, solubilise perfumes in cosmetic formulation and solubilise oily substances (interesting in make-up removers for example). Lipolami is a multi-active ingredient, for the new generation of cosmetics.