Synthetic Amorphous Silica: EU Committee Issues an Opinion

The Scientific Committee on Consumer Safety (SCCS) of the EU has examined the solubility of various forms of synthetic amorphous silica (SAS) and determined both the hydrophilic and the hydrophobic forms of SAS chemicals to be insoluble.

In January 2018, the Association of Synthetic Amorphous Silica Producers (ASASP) submitted a dossier to the EU. With the dossier, the Association wanted to prove the solubility of SAS so that the chemicals would not be considered nanomaterials according to the Cosmetics Regulation, Article 2(1)(k). The claim made in the dossier would have meant that the Association did not need to take any other measures to prove the harmlessness of SAS.

The EU then delegated the matter to the SCCS for a scientific examination of the data in the dossier. The SCCS reached a different conclusion about the solubility of SAS. According authors of the Opinion, the Association incorrectly used an excessively high threshold value for solubility. The Opinion states that the correct value is 33 mg/l instead of the 100 mg/l used by the Association:

  • The hydrophilic SAS materials were reported in the range of 22 to 225 mg/L for solubility tests performed in aqueous media containing up to 0.5% ethanol.
  • The hydrophobic SAS materials were reported in the range of 0.4 to 180 mg/L in aqueous media with up to 10% ethanol.

Other test conditions: Temperature: 19.5-20.5°C, pH: 3-8, Time: 3-49 days

In its Opinion, the Committee admitted that the solubility it found applies only in these conditions. In certain circumstances and under different condition, the solubility could be different.

The consumer portal of the German state of Baden-Württemberg, “Nanotechnologies in Daily Life” (German only) provides a good overview of cosmetics and nanomaterials.

We are pleased to support you regarding all tricky legal issues related to the cosmetics regulation. Please contact us at

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