July, 2022 | Christian D. Nell | christian@isolvents.co.za | Research consultant
BSc Molecular Biology and Biotechnology | Stellenbosch University

Ethanol performs many functions within the industry of cosmetics. The first instance of use is encountered outside the lab. Ethanol is an extraction medium, removes solid particles and separates oils from organic sources. This is common in the cold-press process of making soap. Flowers, roots, and leaves are treated with ethanol to extract active ingredients from the plant material. Subsequently the active ingredients are incorporated into mixtures of soda and fats to yield soap. This is straight-forward and can be done in your home. Even in this rudimental method of extraction, ethanol plays a part that can be applied in laboratories too. Ethanol extraction in labs is of even better value as it makes the extract inherently anti-microbial. At an ethanol concentration of 20% it inactivates and even kills any micro-organisms living on organic material that could be introduced into cosmetic products. This concentration is a standard for hairsprays, perfumes, and anti-bacterial hand gels. However, if ethanol concentrations are higher than 24% the product is flammable and must be labelled so accordingly.

Ethanol is a molecular constituent occurring in different compounds that are mixed for the composition of cosmetic products. It is present in preservatives, thinning agents, emulsifiers, solvents, and surfactants. All of these compounds can be added to make a soap with specific qualities. Ethanol has a function as a surfactant, which is the most advantageous aspect in its purpose for cosmetic science. Surfactants are compounds that bind to the surface of two molecules that otherwise wouldn’t bind together. This gives cosmetologists the liberty to add mineral oils and vital fats – up to a desirable amount – whilst binding it all together in the final homogeneous mixture. In this way, ethanol prevents products from separating and sweating out compounds that trap moisture. This is especially important in a vein of cosmetics known as rheology, where the flow of matter in soft-solids and semi-fluids is determined by the addition of ethanol. It is good to be well versed in rheology as a cosmetologist if you are handling clay. Mixing clay with oil requires a polar activator such as ethanol, which has relatively strong polar forces because of its chemical structure compared to its overall molecular size.

The figure on the right shows the distribution of atoms of an ethanol molecule, and its spatial arrangement. The thicker and dashed lines depict the ethanol molecule in three dimensions. The oxygen atom has two free pairs of negatively charged electrons which set up a charge difference across the molecule. The polarity is determined by the strength of the repulsive force of electrons on the positive charge of the molecule. The positive charge is distributed on the left of the molecule, due to its shape and location of the oxygen atom on the right. As discussed earlier, ethanol is an ideal surfactant in cosmetology for its small molecular size and its strong polarity. This allows it to enter between larger molecules and bind them together even if they’re positively or negatively charged. The table below captures the importance of this characteristic of ethanol. Mainly in three ways for cosmetics.

Safe use of Ethanol in the Cosmetic Industry

There is little research focus on toxic effects of ethanol, especially at the point of impact on skin. Results from studies lack evidence that associates topical ethanol use with an increased risk of skin disease. There is unambiguous evidence that oral ethanol consumption by drinking alcoholic beverages increases the risk of cancer. But does absorption of ethanol through skin add to that risk? This question was answered by a study that evaluated the safety of topical ethanol application. The aim was to verify what cosmetologists had been speculating in the past. Knowing that ethanol on the skin increases penetration of cells, does this mean that entry of undesirable compounds into skin is more likely, and therefore indirectly increase the toxicity of ethanol? This should be well thought through. Since the safe use of ethanol is played off against its desirable effect as a skin penetration enhancer for desirable compounds in cosmetics (Lachenmeier, 2008).

The study concluded three things on topical ethanol use

1. It does not cause systemic toxic effects on un-lacerated skin; (only if it is applied on damaged skin especially in cases of children).
2. Adverse effects include mild skin irritation, or allergic contact dermatitis in cases of genetic dispositions regarding ethanol metabolism
3. One concern is the permeation-enhancing capability of ethanol which can lead to absorption of other topically toxic compounds

Even though the study thwarts major health concerns, cosmetologists should keep in mind that ethanol is not the ideal solvent or surfactant always. Alternative surfactants can be used for people with skin disorders relating to genetic disorders and contact dermatitis.

Cosmetologists from L’Oréal have insight in the way they use ethanol in their products. It carries out three main functions that need to be covered by other surfactants when ethanol is not used. The three functions are volatility, solubility, and facilitation of skin penetration. Volatility describes the rate of evaporation of a compound and its readiness to change from liquid to gas. This means that solvents like ethanol evaporate quickly after use, disappearing readily as it is sprayed or rubbed on the skin. A good solvent that acts as a solubilizing agent will be a vehicle that offloads active ingredients at the surface of the skin whilst evaporating from it at the same time. This will cool down the skin and make it contract, which facilitates skin penetration.

An alternative surfactant to ethanol is denatured alcohol. Denatured alcohol has specific additives that give it a bad taste and sharp smell to discourage recreational consumption of alcohol (especially at the high quantity and concentration in cosmetic products). Some additives have been safety checked and proven to be of good use by the CIR (cosmetic ingredient review). They have laid down good parameters by defining which additives can be used to make specially
denatured alcohol (SD alcohol) for an intended purpose. In their published article in the international journal of Toxicology in 2008, they list four standardized additives by which ethanol can be denatured to change the way it interacts with skin cells to reduce adverse effects. These modifications should be implemented in making cosmetic products if they are to benefit all people groups. In this way we can serve those that have sensitive skin or skin disease.

Ethanol market potential in Nigeria and Zambia

Knowing that ethanol – pure or denatured – is an essential ingredient in almost all cosmetic products; there is unmissable opportunities for growing this industry in Sub Saharan Africa. In some African countries like Nigeria, there exists a well-established ethanol economy. Despite the significant production and distribution of ethanol, their companies cannot meet economic demands for the chemical. In Nigeria, about 90% of the ethanol is still imported, of which most funnels toward consumption in alcoholic beverages, (natural resource institute, 2019). For Nigeria, the sector with the third highest use of ethanol use by quantity is the cosmetics industry. Most of their national ethanol produce is made by cassava farmers that have a specific breed of cassava (CAVA2) to increase the scale of ethanol industry. Nigeria is the world's biggest producer of cassava but it is still short of creating a thriving ethanol industry.

Zambia on the other hand, has different limitations in their soap and detergent industry. High input costs through tax and compliance fees on ethanol imports is an additional barrier in establishing ethanol trade. However, economic developments for both South Africa and Zambia are promising. South Africa’s intent to make key chemicals like ethanol more accessible to Zambia’s cosmetic industry can sustain its growth of Zambia. This is met by regional access to supermarket outlets that Zambia implements for procurement and distribution of local produce, (Teboho et al. 2017). So Southern African companies can push their import of ethanol to Zambia, leveraging Zambian domestic trade of ethanol to meet the need in cosmetic industries.

References

Bosiu, Teboho & Chinanga, Farisai & Das Nair, Reena & Mondliwa, Pamela & Phiri, Mwanda & Ziba, Francis. (2017). Growth and Development in the Cosmetics, Soaps, and Detergents Regional Value Chains: South Africa and Zambia. SSRN Electronic Journal.
Final Report of the Safety Assessment of Alcohol Denaturants. International Journal of Toxicology, 27(Suppl. 1):1–43, 2008.
Lachenmeier D.W. Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity, 3(1), 26–0, 2008.
https://saiia.org.za/saiia-toolkit/growth-and-development-in-the-cosmetics-soap-and-detergent-regional-value-chains-south-africa-and-zambia/
https://guardian.ng/business-services/investing-in-industrial-ethanol-production/
https://www.nri.org/latest/news/2019/cava2-and-ethanol-the-perfect-cocktail-for-cassava-farmers-and-large-scale-industry
https://inside-our-products.loreal.com/ingredients/alcohol-cosmetics