Debunking sunscreen myths part 2
Some people differentiate between soluble and insoluble sunscreen particles, grouping them into two types of UV filters, ‘physical’ and ‘chemical’ - but thinking about them in this way has led to many people misunderstanding how sunscreen really works to protect the skin. ‘Experts’ on television and media continue to propagate this way of differentiating between soluble and insoluble filters, often stating that chemical filters work by absorbing UV rays, while physical filters work by scattering and reflecting.
It’s time to truly ‘scatter’ this idea to the wind!
The truth is that UV filters work by blocking different wavelengths; whether these are UVB or UVA rays.
Some sunscreens have ‘physical’ filters consisting of titanium dioxide (TiO2) and zinc oxide (ZnO), and while they do have scattering and reflective properties, it is not because of these properties that they become effective sunscreens! Rather, it is because of its semiconductor-like electronic properties as solids. The emphasis on scattering and reflecting on one hand, and absorbing on the other, through the ‘chemical’ and ‘physical’ grouping of UV filters is technically incorrect, as ‘physical’ blockers also absorb UV rays.
Truth be told, the scattering and reflective properties of titanium dioxide (TiO2) and zinc oxide (ZnO) in sunscreen is quite undesirable for consumers and formulators. When applied on skin, the consistency is thick, gooey and leaves a pale white sheen (also known as the dreaded ‘white cast’). To avoid this, the particles of these physical UV filters must be extremely small - less than 100nm.
So, how much of these scattering and reflective properties in ‘physical’ UV filters contribute to the effectiveness in protecting our skin? The answer: According to academic research, it is no more than a staggering 15%! So, before you or someone else claims that ‘physical’ filters only block UV rays, think again!
BASF’s Tinosorb® M
BASF’s Tinosorb® M is uniquely both an organic and inorganic sun care formula, the first in the market to utilise organic microfine particle technology to act as a micropigment and organic UV absorber.
It is highly efficient because of its triple action:
- UV absorption by its photostable organic molecules
- Light scattering by its microfine structure, and
- Light reflection by its microfine structure
* Always read the label, use only as directed
Interested in learning more? Contact us so we can share our insight and expertise in developing solutions for the sunscreen industry.
1. Schlossmann D., et al. Sunscreens-regulations and commercial development, cosmetic science and technology,3rd edn, Series 28. Boca Raton, FL: Taylor &Francis,2005,239-279
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