Are Nano Zinc & Titanium Dioxide Safe? What Penetration Studies Show
The fear that nanoparticles slip into your bloodstream is widespread - here's what the actual penetration studies, including a major regulatory review, found.
The large majority of studies, including a major TGA literature review, find that nano-sized zinc oxide and titanium dioxide do not penetrate beyond the stratum corneum into living skin, and human studies show negligible systemic absorption.
Australia's Therapeutic Goods Administration concluded from its literature review that nano-sized zinc oxide and titanium dioxide remain on the skin's surface and outer dead-cell layer, and are unlikely to reach living cells - supporting their safety in topical sunscreens.
Questions we get a lot
Do nanoparticles in sunscreen get absorbed into the body?
The weight of evidence says no. A major TGA literature review found that nano zinc oxide and titanium dioxide do not penetrate beyond the stratum corneum, the outer layer of dead skin cells, into living skin. Human studies show negligible systemic absorption.
Are nano mineral sunscreens safe to use?
Based on the available research, including the TGA review, nano-sized zinc oxide and titanium dioxide used in sunscreens are considered safe for topical use because they stay on the skin's surface. They also offer the cosmetic advantage of being less visibly white than larger particles.
Where did the 'nanoparticles are dangerous' idea come from?
Concern arose because nanoparticles are very small, raising questions about whether they could cross the skin barrier. The TGA's review of the scientific literature addressed this directly and found they do not penetrate beyond the stratum corneum into living skin in normal use.
r/SkincareAddiction: 'I keep seeing posts that nano mineral sunscreens get into your organs - is there real science behind that?'