SCCS/1653/23: HC Blue 18 in Hair Dye Products Assessed as Safe up to 0.35%

The Scientific Committee on Consumer Safety (SCCS) has re-assessed the hair dye HC Blue 18. In its opinion SCCS/1653/23, adopted on 27 April 2023, the Committee concludes that use in hair dye products is safe under certain conditions. At the same time, the SCCS classifies the substance as a moderate sensitiser.

What the SCCS assessed

The SCCS is an independent advisory body of the European Commission. It assesses the health safety of cosmetic ingredients and thereby provides the scientific basis for subsequent regulatory decisions. An SCCS opinion is not itself a legal act, but a scientific assessment.

The subject of opinion SCCS/1653/23 is the substance HC Blue 18. The key data from the source material:

• Substance name: HC Blue 18
• Colipa number: B122
• CAS number: 1166834-57-6
• Use: hair dye in non-oxidative as well as oxidative hair dye products

This is a second submission (Submission II). The SCCS took into account new physicochemical data underlying the assessment.

The outcome of the opinion

The European Commission asked the SCCS two questions. First, whether HC Blue 18 is considered safe when used in non-oxidative as well as oxidative hair dye formulations up to a maximum on-head concentration of 0.35%.

The SCCS answers: based on the newly submitted physicochemical data, the use of HC Blue 18 as an ingredient in non-oxidative as well as oxidative hair dye products is safe up to a maximum on-head concentration of 0.35%.

The term on-head concentration refers to the concentration of the dye in the ready-to-use mixture that is actually applied to the hair. For oxidative hair dye products, the product is typically mixed with a developer component before application. The on-head concentration therefore refers to the mixture at the moment of application, not to the concentration in a single component before mixing.

Classification as a moderate sensitiser

The Commission's second question was whether the SCCS has any further scientific concerns regarding the use of HC Blue 18 in cosmetic products. Here the Committee states: the SCCS considers HC Blue 18 to be a moderate sensitiser.

Sensitisation describes a substance's potential to trigger allergic skin reactions. Classification as moderate means the substance has a medium sensitising potential. This assessment is relevant for manufacturers of hair dye products because it feeds into the safety assessment of the final product. Beyond this classification, the source material does not mention any further conditions or warnings.

Who is affected by the assessment

Addressed are manufacturers and distributors of hair dye products who use, or plan to use, HC Blue 18. This applies to both non-oxidative and oxidative systems. The SCCS opinion provides the scientific basis on which the European Commission can decide on a possible inclusion in, or adjustment of, the annexes to the Cosmetics Regulation (EC) No 1223/2009.

Important: the opinion itself does not set any transitional periods and does not directly amend the Cosmetics Regulation. It is a scientific assessment. Whether and when the stated maximum concentration of 0.35% will be transposed into binding law is not stated in the source material. The currently applicable annexes to the Cosmetics Regulation remain the authoritative legal reference.

What manufacturers can check now

Those using or planning to use HC Blue 18 can keep the following points in mind:

• Check concentration: verify that the on-head concentration in the ready-to-use mixture complies with the upper limit of 0.35% assessed by the SCCS.
• Classify the type of application: the SCCS assesses both non-oxidative and oxidative formulations. The formulation should be clearly assigned to one of these categories.
• Consider sensitisation: the classification as a moderate sensitiser belongs in the safety assessment of the final product under Annex I.
• Monitor legal developments: since transposition into binding law is still open, it is worth following future amendments to the Cosmetics Regulation.

The full opinion is available as a PDF (SCCS/1653/23, sccs_o_272.pdf) on the website of the European Commission. You can find the document in the SCCS publication on HC Blue 18 (Submission II) as well as in the overview of all SCCS opinions.

Practical implications

The assessment of HC Blue 18 illustrates a recurring pattern: a dye is considered safe within a defined concentration range, but carries a relevant property, in this case moderate sensitisation. For the safety assessment of a hair dye product it is therefore not enough to look solely at the maximum concentration. The sensitising effect and the specific formulation also determine how the final product should be assessed.

At REGULARUS, we take current SCCS opinions into account when preparing the CPSR (Cosmetic Product Safety Report, safety report under Annex I) and incorporate substance data such as that on HC Blue 18 into the assessment of the respective product. This keeps traceable the scientific basis on which a formulation was assessed.