'Nessie' and The Precautionary Principle

By: Johann W. Wiechers, PhD, JW Solutions

Posted: June 1, 2009

Democracy is a good thing, there is no doubt in my mind about that, but it can be taken too far. The word democracy comes from the Greek demos meaning people, and krátos meaning rule or strength. The ancient Greek city states experimented with this system, in which all people had the same access to power and all members enjoyed universally recognized freedoms and liberties. So, one might wonder, how can democracy be taken too far?

This article is not about an initiative of a Dutch political party that wants absolute freedom of speech, including, for example, the right to state that the Holocaust never happened—the party is not suggesting it did not; however, outlandish ideas can only be changed if they can be discussed. Hence, there needs to be absolute freedom of speech. The limit is reached when words instigate hatred and violence. Readers with absolute freedom of speech would probably ask me right now whether this is a political column or one about cosmetic science. The latter, of course, but I need to warm you up since politics are involved in this cosmetic subject.

A little while back, I published a story in Cosmetics & Toiletries magazine on the use of nanotechnology in personal care. The argument was that the majority of manufactured nanoparticles are used to produce sunscreen actives for sun care formulations. These particles, specifically micronized zinc oxide and titanium dioxide, must be nano-sized because customers want to apply a transparent film on their skin. While concerns have been raised that these particles might penetrate the skin, a plethora of studies (approximately 70) have been executed and have failed to show the particles penetrate beyond the stratum corneum. A few studies did show somewhat deeper penetration but in these cases, the results could be attributed to the methodologies used. So, in approximately 70 studies, no experimental evidence was found to support the argument that nanoparticles penetrate the skin.

Theoretical knowledge of skin penetration was applied to these particles, guided by deductions made by Prof. Michael Roberts, PhD, of the University of Queensland, Australia, and it was concluded to be physically impossible for these particles to penetrate normal and healthy human skin. Yet, concerns remain because the safety of these particles could not be irrefutably shown. Safety in fact never can be shown because it is impossible to demonstrate the presence of an absence; one can prove that something is there but not that something is absent. This is much like trying to prove that "Nessie," also known as the Loch Ness Monster, does not exist despite the existence of photographic evidence (see Figure 1).¹

Enter: The impossible situation of proving nanomaterials to be safe. Academia continues to conduct experiments demonstrating that nanoparticles do not penetrate into the deeper layers of the skin but skeptics and activist groups do not accept this evidence. Academia stresses the impossibility of declaring that something is completely safe, and they are right. Water may be the safest place for Nessie to hide but humans can drown in it. Therefore, cosmetic scientists must continue experimenting until skin penetration is found—much in the same way as the general public should continue looking for Nessie.