Glossary

Nanoparticle

Written by Reviewed by the SYNC editorial team Published Last reviewed Editorial standards

Nanoparticle — an extremely small particle, generally defined as measuring between roughly 1 and 100 nanometers in at least one dimension. In skincare, nanoparticles appear in some mineral sunscreens and delivery systems, where their small size can affect texture, appearance, and how ingredients are dispersed in a formula.

Key points

  • A nanometer is one billionth of a meter, so nanoparticles are far smaller than what the eye can see.
  • Nano-sized zinc oxide and titanium dioxide are used in some mineral sunscreens to reduce the white cast left on skin.
  • Regulatory bodies such as the EU require certain nanomaterials to be labeled with the word nano in the ingredient list.
  • Current scientific reviews generally indicate that nanoparticles in sunscreen remain on the skin's surface and do not penetrate healthy intact skin.
  • Nanotechnology is also explored for encapsulating and delivering active ingredients within formulas.

Frequently asked

Are nanoparticles in sunscreen safe?

Regulatory and scientific reviews generally conclude that mineral sunscreen nanoparticles stay on the surface of healthy, intact skin and are considered safe for topical use, though research continues.

Why are nanoparticles used in mineral sunscreens?

Reducing zinc oxide or titanium dioxide to nano size helps the sunscreen spread more easily and leaves less visible white cast while still providing UV protection.

Related topics

This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.

Encyclopedia

Further reading

This entry was written and checked against the sources below. They are published by clinical and scientific bodies, they are listed most readable first, and each one opens in a new tab. They are background for the whole entry rather than footnotes to individual sentences.

  1. Introduction to Sunscreens and Their UV Filters - Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen… StatPearls (NCBI Bookshelf) Reference text ncbi.nlm.nih.gov
  2. Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen U.S. FDA Regulatory and safety fda.gov
  3. Sunscreen: How to Help Protect Your Skin from the Sun U.S. FDA Regulatory and safety fda.gov
  4. Ultraviolet Filters: Dissecting Current Facts and Myths PubMed Central Peer-reviewed, open access pmc.ncbi.nlm.nih.gov
  5. A short review of alternative ingredients and technologies of inorganic UV filters PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov
  6. Synergy effects between organic and inorganic UV filters in sunscreens PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov

SYNC does not publish medical advice. Nothing here replaces a consultation with a doctor or a pharmacist about your own skin.