INGREDIENT INTRODUCTION: Nano-Particles
Posted 14 February 11A few months ago, we talked about the use of nano-technology in sunscreens. In this issue we’ll further discuss nano-technology and provide more proof on the safety of nano-particles in sunscreens. Nano-technology has been used in sunscreens for many years now. Zinc oxide and titanium dioxide are two of a number of ingredients with proven ability to protect skin from damage due to ultraviolet radiation.1
Zinc oxide and titanium dioxide are particularly valuable because of their ability to filter UVA as well as UVB light, giving broad protection from damaging sunlight.1
Historically, when used in sunscreens, zinc oxide and titanium dioxide are visible, giving the skin a white colour.1 This effect can be reduced when these chemicals are used in nano-particle form, where they cannot be seen on the skin but still retain the sun-screening properties of the coarser material.1
Recently, there have been questions raised about the safety of sunscreens that contain nano-particles.1 The concern is that if nano-particles were to be absorbed into skin cells, they could possibly interact with sunlight to increase the risk of damage to these cells.1 Ongoing scientific research continues to conclude that nano titanium dioxide and zinc oxide used in sunscreens do not pose a risk to human health.
In Australia, sunscreens with an SPF of over 15 and sunscreen components are regulated through the Therapeutic Goods Administration (TGA). In early 2009, the TGA conducted an updated review of the scientific literature in relation to the use of nano-particulate zinc oxide and titanium dioxide in sunscreens.1
The TGA review concluded that:
The potential for titanium dioxide and zinc oxide nano-particles in sunscreens to cause adverse effects depends primarily upon the ability of the nano-particles to reach viable skin cells; and to date, the current weight of evidence suggests that titanium dioxide and zinc oxide nano-particles do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer of the skin that is composed of non-viable cells.1
1. Therapeutic Goods Administration. TGA Fact Sheet – Sunscreens [online] 2010 [cited 11 February 2011]. Available from URL: http://www.tga.health.gov.au/npmeds/sunscreen-zotd.htm
