Cosmetic Regulation Europe

Cyclotetrasiloxane (D4), Cyclopentasiloxane (D5) and Cyclohexasiloxane (D6)


BIORIUS Information Letter 118: The so awaited D4, D5 and D6 restrictions in wash-off and leave-on cosmetic products are notified


The Draft Regulation on Cyclotetrasiloxane (D4), Cyclopentasiloxane (D5) and Cyclohexasiloxane (D6) has been notified to the World Trade Organization (WTO) on the 22nd of June (HERE and HERE). This Regulation will amend the Annex XVII of the REACH Regulation and it is expected to be adopted in Q4 2023. The restrictions applicable to cosmetics are described below.

Cyclotetrasiloxane (D4):
Already forbidden in the cosmetic products. Only technically unavoidable traces are tolerated at the max levels below:
– In wash-off products: already restricted at max 0.1%
– In leave-on products: max 0.1% from Q4 2026
Cyclopentasiloxane (D5)
– In wash-off products: already restricted at max 0.1%
– In leave-on products: max 0.1% from Q4 2026
Cyclohexasiloxane (D6)
– In wash-off products: max 0.1% from Q4 2025
– In leave-on products: max 0.1% from Q4 2026


We hope that this will be of help and stay at your disposal for any questions related to this topic. Should you have any question, please, feel free to contact your CRM (Customer Relationship Manager) or contact us directly:


Thanks to Stéphanie Annet for writing this article.


To assist us in enhancing our regulatory articles and news, we kindly encourage you to provide your thoughts by utilizing the thumbs-up/thumbs-down buttons located below the article. Your feedback will remain anonymous.

Get in Touch

Need a piece of advice, a quotation or answers to your questions? Contact us…

Fill in this form or contact us directly: We will answer as soon as possible!

As specialists in cosmetic Regulations for more than 15 years, Biorius offers a reliable turnkey solution for placing cosmetic products in various markets:

  • First Class specialists in cosmetic regulations in Europe, the United Kingdom, the United States, and in more than 60 countries
  • 50 regulatory experts, toxicologists, pharmacists, and chemists to serve you.
  • A unique model that guarantees you both the fastest turnaround possible and high-quality services. Curious? Ask us to know more!
  • No hidden costs: Biorius does not charge you for any question, call, or meeting.
  • A best-in-class IT tool, free of charge, and saving a lot of your time.
  • More than 1,500 international clients have already chosen Biorius!
  • We evaluated more than 100,000 products and never had any compliance issues (fines, withdrawals from the market, etc.) in 15 years of existence.


  • Frédéric Lebreux

    Dr. Frédéric Lebreux is Biorius's Chief Executive Officer and has worked in the cosmetic industry for more than 13 years. He is regularly invited as a speaker or Professor to cosmetic events.

    View all posts