Silica: A Powder with a Nano-Scale Debate on the Horizon
Arin Editorial · how this is made
When you see 'Silica' on a label, it is an inorganic solid made of silicon and oxygen. It can be derived from natural minerals or produced synthetically. The amorphous form is the most common in cosmetics and is at the center of the discussion.
What is silica?
Silica consists of silicon-oxygen tetrahedral units. Depending on how the atoms are arranged, it takes different physical forms. Amorphous silica has an irregular, non-crystalline structure. The CIR panel bases its assessment on synthetic amorphous silica; the method of manufacture is considered decisive for safety.
What do the CIR data say?
The panel reviews acute toxicity, eye and skin irritation, and genotoxicity data. In a study where silica and hydrated silica were ingested, no significant change in renal silica excretion was observed. These data form the basis of CIR's safety assessment.
What does the IARC classification mean?
IARC has classified amorphous silica as Group 3. This means there is not enough evidence to say it causes cancer in humans. But it does not mean 'definitely safe' either; IARC assesses hazards, not the doses and exposure in cosmetics.
Why is it being re-evaluated?
The European Commission has asked the SCCS for a new safety opinion on four nano silica ingredients used in cosmetics. The reason is the uncertainty around biological effects at the nanoscale. This is a precautionary step, not a ban.
There is no specific restriction on amorphous silica in cosmetics; a new SCCS opinion on nano silica is pending.
Don't panic when you see 'Silica' on a label. There is no current restriction on amorphous silica. For products containing nano silica, it's best to wait for the European evaluation.
Sources
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CIR (Cosmetic Ingredient Review) Safety Assessment
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IARC Monographs