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Sunscreen filters

Titanium dioxide

Also listed as TiO2, CI 77891, mineral sunscreen, E171

Mineral UV filter in sunscreens and a white pigment in toothpaste. Strong on UVB, weaker in long-wave UVA; the concerns are about inhaling or swallowing it, not skin contact.

Strong evidenceTypical strength: Up to 25% as a sunscreen filter (US and EU); small amounts as a pigment in toothpaste

What it is

Titanium dioxide does two jobs in this catalogue. In sunscreens it is a mineral UV filter: very effective against UVB and short-wave UVA, less so against long-wave UVA1, so it is usually paired with zinc oxide or an organic UVA filter. Like zinc oxide it is photostable and rarely causes allergy.

In toothpaste it is simply a white colourant (listed as CI 77891) that makes the paste look bright. It does not whiten teeth.

How strong is the evidence?

Strong evidence

As a sunscreen filter its protection is measured directly in SPF testing, and it is one of the three filters the FDA currently regards as safe and effective. Safety questions concern other routes: EFSA concluded in 2021 that swallowed particles could not be ruled out as genotoxic, which ended its use as a food additive in the EU, and inhaled fine powder is classed as a possible carcinogen based on rat studies. Neither is a finding of harm from use on skin.

What it's used for, checked

UVB protection

Holds up

Strong UVB and UVA2 blocker; needs a partner filter for full UVA1 coverage.

Whitens teeth (in toothpaste)

False

It only colours the paste. Whitening in toothpaste comes from abrasives or peroxide.

Safe to swallow in toothpaste

Mixed

The EU banned it in food in 2022 after EFSA could not exclude genotoxicity. In 2024 the EU's cosmetics committee said the data could not rule this out for most grades used in oral products either; it remains permitted in toothpaste while more data are reviewed.

Works well with

  • zinc-oxide

Who should be careful

  • Avoid inhaling powders and sprays; in the EU, nano titanium dioxide is not allowed in products that could be inhaled, and fine powder is classed as a suspected carcinogen by inhalation.
  • Toothpaste: children swallow more, so use the recommended amount (a smear under 3, pea-sized from 3 to 6). If you would rather avoid swallowed titanium dioxide, pigment-free pastes exist.
  • Allergy is very rare.

The studies

Every citation is checked against its PubMed record.

  1. Safety assessment of titanium dioxide (E171) as a food additive.
    EFSA Panel on Food Additives and Flavourings (FAF), Younes M, Aquilina G, et al. · EFSA J · 2021 · Regulatory risk assessment

    EFSA found no organ or reproductive toxicity at high doses, but could not rule out that swallowed titanium dioxide particles damage DNA, and concluded it could no longer be considered safe as a food additive. This led to the EU food ban; it is not a finding about skin use.