Titanium dioxide in sunscreen: nano, sprays and safety

What titanium dioxide does in a sunscreen

Titanium dioxide is added to some sunscreens to physically block ultraviolet radiation.¹ It is a mineral filter, so it works on the surface rather than being absorbed to do its job.

On a label it comes in two forms. Plain Titanium Dioxide is the ordinary one, and Titanium Dioxide [nano] marks the nanoparticle form. Snifff has a separate entry for each.

Does it get into your skin?

A minipig study applied sunscreens with 5% titanium dioxide, in three forms (submicron, nano, and coated nano), four times a day, five days a week for four weeks. Titanium levels in the lymph nodes and liver did not rise above those of untreated animals. The particles turned up in the outer skin layer and the upper hair follicle, with a few isolated particles in the dermis that looked more like contamination than a pattern. The authors concluded there is no significant penetration through intact, normal skin.¹

An older study of coated microparticles found much the same. The deeper layers of the horny layer had none, and the only place particles showed up was in the hair follicle openings, at under 1% of the amount applied. Nothing reached living tissue.²

Sunburnt skin is a fair test, since that is when people are most likely to reapply. In pig skin with UVB sunburn, titanium dioxide nanoparticles in an oil-in-water formula went 13 layers into the stratum corneum, against 7 in normal skin. No transdermal absorption was detected.³

The EU view on nano titanium dioxide and sprays

The EU's Scientific Committee on Consumer Safety looked at nano titanium dioxide in sunscreens and concluded that it is unlikely to cause systemic exposure through human skin, acute toxicity from skin contact or accidental swallowing, or skin and eye irritation or sensitisation on healthy skin. The same passage carries the limit that matters: none of that applies to sprays that may lead to inhalation, which may result in lung inflammation.⁴

The committee was also candid about what it could not settle. Some titanium dioxide nanoparticles have been shown to damage DNA, but negative results exist too, so the evidence is not conclusive. Titanium dioxide particles have also shown carcinogenic effects after inhalation, which is the reason sprays are treated differently.⁴

That is the context for Snifff's summaries above. The practical difference is simple: a cream stays on you, a spray gets breathed in. In the Cosmetics Regulation, Annex VI, entry 27a allows nano titanium dioxide at up to 25%, not for applications that may expose the lungs to inhalation.⁵ The India half is Snifff's.

Titanium dioxide in pregnancy and breastfeeding

Evidence on cosmetic products in pregnancy is limited overall, so ask your doctor or midwife about the specific product you use.⁶

What you will see on the label

On a label, look for Titanium Dioxide and Titanium Dioxide [nano]. Snifff shows it as Low risk. For the rest of the formula, see what the score means and how to read the list.

As Snifff shows it

Titanium dioxide

Titanium Dioxide

Low risk

Pregnancy and nursing

We found no pregnancy- or lactation-specific evidence for this ingredient.

Regulatory gap

The EU bars nano titanium dioxide in sprays when it could be inhaled. India does not distinguish nano from non-nano forms in spray products.

Titanium Dioxide [nano]

Low risk

Pregnancy and nursing

We found no pregnancy- or lactation-specific evidence for this ingredient.

Regulatory gap

Both regions permit this nano UV filter at up to 25%. The EU bars sprayable uses that could be inhaled; India does not make the same distinction.

Wording as it appears in the extension, which can change between releases.