For nearly 70 years, silicones have infiltrated our cosmetics formulae and become essential ingredients for the industry by bringing many beauty products a soft touch and smooth appearance, all at reduced cost.
But in fact, everything comes at a cost. In the case of silicones, It Is the environment that pays the price. It is precisely for this reason, and also due to their petrochemical origins, that silicones have always been banned in organic cosmetics.
Read on to find out more!
What exactly are silicones?
Silicones are inorganic polymers whose molecular structure is made up of silicon and oxygen, via siloxane bonds.
(A short vocabulary explainer: the word ‘organic’ here should not be confused with the same word used in terms such as ‘organic farming’. From a chemical standpoint, an organic molecule contains carbon, while an inorganic substance does not.)
Silicones are compounds that can only be obtained by chemical synthesis, and do not exist in the natural world. Today, there are a lot of derivatives in the silicone family. They come in the form of oils (volatile or non-volatile), elastomers and resins.
In 2021, nearly 1.3 billion tonnes of silicones were produced worldwide! They are extensively used in a range of sectors such as the aeronautical industry, car making, building, textiles, food, health and, of course, cosmetics.
What is the role of silicones in cosmetics?
As cosmetic ingredients, silicones are primarily used in creams, milks, lipsticks, etc. for their sensorial properties and/or their water-repellent characteristics.
They can also be found in shampoos and conditioners for their propensity to cling to the surface of hair and skin. In the INCI (international nomenclature of cosmetic ingredients), silicones can be recognised by names including :
CYCLOMETHICONE, CYCLOPENTASILOXANE, CYCLOHEXASILOXANE, TRISILOXANE, DIMETHICONE, DIMETHICONE COPOLYOL, AMINODIMETHICONE, DIMETHICONOL, DIMETHICONE CROSSPOLYMER, VINYL DIMETHICONE CROSSPOLYMER, TRIMETHYSILOXYSILICATE, POLYPROPYLSILSESQUIOXANE and POLYMETHYLSILSESQUIOXANE.
Why should you avoid silicones in your cosmetics?
- Silicones and your health
Owing to their highly stable chemical structure, both from biochemical and physical perspectives, silicones are considered to be “safe” for cosmetic use. They are neither irritant nor allergenic, and are also considered to be non-comedogenic.
However, questions often arise as to the safety of silicones! Cyclotetrasiloxane (D4), for example, has been banned since 1 January 2022 under European Regulation (EC) No. 1223/2009 on cosmetic products, as this silicone is strongly suspected to be an endocrine disruptor.
Current research does not clearly indicate any harmful effects of other silicones on our health.
- Silicones and environmental harm
However, silicones are disastrous for the environment. Considering on the one hand their non-biodegradability and on the other the classification of some as persistent bioaccumulative toxic substances (PBTs), their use in cosmetics should be halted.
As mentioned above, the highly resistant chemical structure of silicones plays a role in their (non) biodegradation. It makes some silicones very slow to biodegrade, while others are entirely non-biodegradable (the right conditions for partial degradation are rarely met).
Silicones found in rinse-off cosmetics (shampoo, shower gel, hair masks) inevitably end up in wastewater. And a substantial share of this wastewater is not processed in wastewater treatment plants, but instead is discharged straight into the natural world. As a result, silicones pollute the earth and the oceans, representing a threat to biodiversity.
Even the silicones that successfully get through wastewater treatment plants can seriously disrupt anaerobic digestion process, contaminating the biogas used by industry (heat), households (for heating, hot water, cooking) or as fuel (bioCNG).
Even worse than their almost total inability to biodegrade, Cyclopentasiloxane (D5) and Cyclohexasiloxane (D6) are being, or are due to be, restricted in their use, as they are considered to be persistent bioaccumulative toxic substances.
A 0.1% ceiling is already in place on the use of Cyclopentasiloxane (D5) in rinse-off cosmetics. Over the next two years, the same limit is due to be imposed on D5 in leave-on products, and on Cyclohexasiloxane (D6) in both rinse-off and leave-on products.
What silicone alternatives are used in organic cosmetics?
Organic cosmetics can offer pleasant sensorial textures through the use of natural alternatives! Organic cosmetic brands formulate their products with ingredients such as squalane, essential fatty acids, (omega-3, omega-6) or plant esters such as Avocado Oil Polyglyceryl-6 Esters, Shea Butter Ethyl Esters, and so on.
So, do you think you can do without silicones?