D4, D5, and D6 in cosmetic products  –  Draft proposal for new use restrictions


The European Commission has notified a proposal to amend Regulation (EC) No. 1907/2006 of the European Parliament and of the Council, concerning the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH), specifically in relation to the ingredients D4 (Cyclotetrasiloxane), D5 (Cyclopentasiloxane), and D6 (Cyclohexasiloxane).

These components are known for their predominant use in the cosmetics industry to deliver smoothness and conditioning to skin and hair. They work by creating a protective film that envelops hair strands and skin surfaces, resulting in a visibly smoother and more hydrated appearance.

Why has this amendment come out?

It’s remarkable the utilization of D4 and D5 in cosmetic products has been subject to regulations since 2020, owing to their persistent and highly bioaccumulative (vPvB) properties, thereby signifying a significant environmental impact. Furthermore, it has been identified that D5 and D6 exhibit persistent, bioaccumulative, and toxic (PBT) properties when they contain 0.1% or more in weight of D4. In this context, D4 itself displays PBT properties at its minimum concentration.

The main objective of this Amendment is to strengthen and expand existing restrictions on D4 and D5 ingredients in rinse-off and leave-on products.

What risk do they have? How it will affect?

Consequently, these legal implications with current restrictions have been incorporated into European Union Cosmetic Regulation 1223/2009 as follows:

Chemical NameINCICAS No.Existing restrictionsProposed restrictions
Cyclopentasiloxane541-02-6Without restrictions< 0,1%< 0,1%< 0,1%
Cyclohexasiloxane540-97-6Without restrictionsWithout restrictions< 0,1%< 0,1%

The substance D4 maintains the prohibition of use, and D5 and D6 may be used both in rinse-off and non-rinse cosmetic products at a concentration always less than 0.1% in the final product.


Proposed date of adoption this draft is on 4th quarter of 2023. Once it will entry into force, there are 20 days from publication in the Official Journal of the EU.

INCICAS No.Limit date
Cyclotetrasiloxane (D4)556-67-2ForbiddenForbidden
Cyclopentasiloxane (D5)541-02-63 years after the entry into force of this amending Regulation.< 0,1%
Cyclohexasiloxane (D6)540-97-62 years after the entry into force of this amending Regulation.

After this period, there must not be cosmetic products for sale in the European market which do not comply with these restrictions.

How Cosmeservice can help you?

Cosmeservice and its team of experts in cosmetic regulation is at your disposal, f you wish to get more information about this subject or receive regulatory support feel free to contact us at info@cosmeservice.com.

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