Cyclosiloxanes are often referred to as cyclotetrasiloxane (D4) and cyclopentasiloxane (D5) because of their antistatic, emollient, moisturizing, solvent, viscosity-controlling, and hair-conditioning properties in cosmetics.
However, concerns have been raised about its toxicity and impact on the environment, and cyclotetrasiloxane (D4) is now recognized to be toxic to the human reproductive system
It also accumulates in the environment, causing unpredictable long-term effects.
Cyclopentasiloxane (D5) may also be harmful to the environment and the European Commission published an update in January 2018 amending Annex XVII of REACH Regulation (EC) No 1907/2006.
After January 31, 2020, the concentration of D4/D5 in cosmetic products placed on the market and rinsed off after application should be less than 0.1% by weight of both substances. This has now been modified to include cyclohexasiloxane (D6) and it is expected that the restriction will be extended to include leave-on products.
Due to these limitations, most silicone alternatives have been designed to replace D4/D5. Without necessarily ruling out silicone products, Innospec recommends that Volasil 8100 (INCI: dimethicone, trisiloxane) provides the right combination of volatility, lubricity and spreadability to give hair and skin products a dry, smooth finish.
It has a similar volatility to D4 and is recommended for antiperspirants and hair sprays that require fast drying times. Volasil DM-1.5 is a dimethicone that is slightly more volatile than D5. It gives hair and skin products a dry, smooth finish.
Innospec’s Dimethisil DM-5 and Dimethisil DM-6 are recommended as alternatives to D6 in hair and skin products, as solvents for active ingredients and as diluents for silicone rubbers and elastomers.
