Continue reading Little Dragon's series on all things sunscreen! If you missed out on part 1 where we tackle the topic of SPF and sunscreen regulation, you can find it here. In part 2 we will explore the difference between chemical and natural UV filters as well as take on the topic of nano particles...
Chemical versus Physical UV Filters
When it comes to sunscreen manufacture there are are a huge number of possible UV filters available on the market, however these can be categorised into two types of active ingredients - chemical and physical.
Physical UV filters are inorganic compounds such as Zinc Oxide (ZnO2) or Titanium Dioxide (TiO2) which reflect and scatter the UV rays. Both of these compounds are naturally occurring and constitute the main ingredients in all natural sunscreens. Little Dragon Natural SPF50 Sunscreen uses Zinc Oxide as its primary active ingredient.
Chemical UV filters are organic chemical compounds (don't be confused with Organic farmed ingredients) with names like oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate that absorb and disperse UV rays. These compounds are used in the majority of sunscreens on the market as they are generally very cost effective and provide good protection from UVA and UVB. The trouble with these types of ingredients is that lab research suggests that they are absorbed through the skin and may mimic hormones causing unintended health consequences. These ingredients are also known skin irritants with large numbers of allergic reactions, especially amongst young children. Chemical filters are also inherently unstable as they are designed to react with light and need to be stored very carefully to not jeopardise their effectiveness.
Nano Particles - What are they?
The issue in the sunscreen industry today stems from consumer preference for specific products. Most people prefer sunscreens that feel good on the skin (aren’t heavy or greasy) and disappear when applied. As with most things in life the sunscreens that provide the best protection are the heavy, white sticky ones that don’t feel good to apply. A physical UV filter like Zinc Oxide provides great protection against UVA and UVB rays, is very stable and has low skin irritation, however it is thick, white and heavy so doesn’t perform well ‘cosmetically’.
To overcome these ‘cosmetic’ issues scientists are working to create compounds with smaller particles termed ‘nanoparticles’. A ‘nanoparticle’ is loosely defined as a particle with a size of between 1 and 100nm (1nm = 0.00000001 m) and are all around us. Every atom that makes up every physical and living thing in the world around us is a nanoparticle or a cluster of nanoparticles. The Zinc Oxide compound used in sunscreens is no different and is made up of many clusters of nanoparticles held together in a lotion or cream. The smaller these particles are the better dispersed they are in the lotion or cream and the better protection they provide from the sun’s harmful rays.
Any sunscreen manufacturer claiming to use ‘non-nano’ or ‘micronized’ Zinc Oxide is preying on the semantics of the definition for nanoparticles (as proposed by the FDA) and are being misleading. Scientific evidence shows overwhelmingly that particles greater than 30nm applied to the skin in a cream or lotion do not enter the blood stream and are not a threat to human health.
The Environmental Working Group (EWG) recommends the use of nano mineral sunscreens over chemical sunscreens. There is no evidence to suggest that nano-particles of Zinc Oxide are able to penetrate healthy human skin. By contrast chemical sunscreen ingredients have a molecular size much smaller than nano-particles and are actually designed to be absorbed into the skin.
So that concludes our two part series on all things sunscreen! Please feel free to send us through any further questions or comments, we are more than happy to answer all of your questions. Have a great summer, and don't forget to slip, slop, slap and wrap!
If you'd like to try out a natural sunscreen this summer, be sure to check out Little Dragon's SPF 50 sunscreen here.