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Zinc oxide

Zinc oxide in skincare: UV filter, skin protectant. What it does on skin, how strong the evidence behind the claim actually is, the concentrations in normal use, who reacts to it, and where it stands in pregnancy and sunlight. On a label it appears as Zinc Oxide.

Soothers, protectants and acne activesUV filter, skin protectantEvidence: Strong

On the label: Zinc Oxide. Also called: Mineral sunscreen filter, calamine, nappy cream.

This is an ingredient reference, not a diagnosis and not a treatment plan. It describes what substances are and what the published evidence supports; it does not tell you what your skin has or what to put on it. A rash that spreads, hurts, weeps, does not settle, or comes with feeling unwell is a reason to see a doctor or pharmacist, not to change serum.

What it is

A white mineral powder used in two quite separate ways: as a broad-spectrum ultraviolet filter in sunscreen, and as a skin protectant in nappy creams, calamine and barrier ointments. It is one of very few single filters that covers ultraviolet B and reaches well into the long ultraviolet A range, which is why it appears in products aimed at sensitive skin and small children.

What it does on skin

As a filter it attenuates ultraviolet light mostly by absorbing it, with some scattering — the picture of a mineral filter reflecting light like a mirror is outdated. As a protectant it forms a physical layer that keeps moisture, urine and friction off inflamed skin, which is exactly what a nappy-rash cream needs to do and why the traditional thick white paste still outperforms most alternatives.

What the evidence is worth

Evidence: Strong

Strong on both counts. Its ultraviolet attenuation is measured and regulated; its protectant role in nappy rash and weeping skin is long established. What the evidence does not support is the belief that a mineral filter protects better than a modern organic filter — protection depends on the finished formulation and, above all, on how much you apply and how often you reapply.

How it is used

In sunscreen, applied generously and reapplied — the amount used in the lab test that produces the SPF number is far more than most people apply. As a barrier paste, thickly, on the affected area, replaced rather than scrubbed off at each change. The two uses have nothing in common except the mineral.

Typical concentration in normal use: Up to 25% as a UV filter in the EU. That is a description of the market, not a recommendation, and it is not a dose.

Who reacts to it

Very low irritation and allergy rates, which is why it dominates children's and sensitive-skin sunscreen. The practical complaint is the white cast, which is worse on darker skin, and the chalky feel of high-percentage formulas.

Pregnancy and breastfeeding

Generally considered fine

No pregnancy concerns, and mineral sunscreens are the ones most often recommended during pregnancy — partly on precaution and partly because pregnancy-related pigmentation is driven by sun exposure and needs daily protection.

Sunlight

It is a UV filter

This is a sunscreen ingredient. It attenuates visible light as well as ultraviolet, which is the cause of the white cast and also the reason tinted mineral sunscreens containing iron oxides are recommended for melasma, where visible light contributes to the pigmentation.

Rules and labelling

In the EU zinc oxide is a permitted ultraviolet filter up to 25%. Nano forms are permitted only to specifications assessed by the Scientific Committee on Consumer Safety and must be labelled with "[nano]" after the ingredient name, and uses that could lead to inhalation exposure — sprays and loose powders — are not permitted.

What it goes with, and what it does not

It is the last step of a morning routine, over any serum and moisturiser. Diluting sunscreen by mixing it into moisturiser or foundation reduces the protection you get and is the most common way people end up with less than the number on the bottle.

One thing people get wrong

The myth is that a mineral filter sits on top as a physical mirror while chemical filters are absorbed and dangerous. Zinc oxide mainly absorbs ultraviolet too, and nano zinc oxide has been assessed by EU safety committees and does not penetrate intact skin in the way the internet suggests. Choose a sunscreen you will actually apply properly: that decides your protection far more than the filter type.

The nutrition side

Skin is fed from the inside as well as treated from the outside, and the two are far less interchangeable than either industry suggests. The relevant page on this site: Foods highest in zinc.

Sources: EU Cosmetics Regulation (EC) No 1223/2009 and its annexes, as published in the European Commission's CosIng database, for every statement about what is permitted, restricted or banned · opinions of the Scientific Committee on Consumer Safety (SCCS) and safety assessments of the Cosmetic Ingredient Review (CIR) for the concentration positions · standard dermatology reference material for mechanism, tolerability and contact-allergy patterns · checked 2026-09-06. Deep links are deliberately omitted where a stable public URL could not be confirmed.

Frequently asked questions

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