Zinc Oxide

What is zinc oxide and what does it do?

Zinc oxide is a white inorganic compound formed from zinc and oxygen. In sunscreens it both reflects and absorbs light. Its most important advantage is that it is one of the few filters that on its own covers short- and long-wave UVA and most of UVB.

In skincare it also has a mild drying and soothing effect. Because it forms a protective layer against wetness and friction in the nappy area, it is used at high concentrations in nappy rash creams.

Which products contain it?

• Mineral sunscreens, baby and children's sunscreens
• Nappy rash and barrier creams
• Face creams with SPF, tinted moisturisers and powders
• Some deodorants and acne care products

On the label it is listed as Zinc Oxide; when used as a colourant, the code CI 77947 may appear. In nano form, EU rules require the word (nano) after its name.

Is it harmful? The scientific assessment

The EU's scientific committee, the SCCS, has found zinc oxide safe as a UV filter in products applied to the skin, in both normal and nano form, up to a certain maximum. Studies show that even on intact skin, and on skin mildly damaged by the sun, nano particles do not pass into the living layers of the skin to any significant extent.

The only concern relates to inhalation. For this reason the EU does not permit nano zinc oxide in spray applications that could lead to inhalation. In the US, the FDA has also proposed zinc oxide as one of two sunscreen filters generally recognised as safe and effective based on the available data; the other is titanium dioxide.

Zinc oxide can be toxic to some aquatic organisms; however, this is more an environmental issue than a matter of human health.

White cast and tips for use

The most common complaint about mineral filters is the whitish cast they leave on the skin. The smaller the particle size, the less noticeable this cast becomes; tinted formulas also give a more natural look on darker skin tones. Applying zinc oxide creams in thin, even layers improves both the look and the protection.

Mineral filters protect immediately after application; even so, they should be reapplied after swimming, sweating or towelling dry.

Who is it suitable for?

• Babies and children: It is often recommended both as a sunscreen and as a nappy rash cream; for babies under six months, however, protection with shade and clothing is recommended first.
• People with sensitive, redness-prone or rosacea-prone skin: It is less irritating than chemical filters.
• People with a history of allergy to chemical filters: It is a good alternative.