Benefits of organic & inorganic UV filters

With the ever-growing popularity of sunscreens, it is important for the formulator to use the most effective and efficient strategies to maximise the protection potential of each UV filter within a formulation. Studies have shown that exploiting the synergistic effects of a combination of organic and inorganic UV filters can greatly benefit the overall formulation by allowing for higher solids loading, less interaction with organic UV filters and lower costs per unit of SPF. The synergy benefits of using both types of UV filters are well documented and are based upon the different mechanisms of protection from each type of UV filter working differently to each other but also working well together. This has previously been demonstrated in a study using the Monte Carlo calculation, which used typical optical parameters of the skin to characterise the synergy effect when organic and inorganic UV filters are used together. This proved that the synergistic performance is caused by light scattering from inorganic UV filters in combination with organic UV filters.1

As awareness of the harmful effects of UV light increases, the need for effective sun protection products becomes a necessity. At present in the UK alone there are approximately 16,200 new melanoma skin cancer cases every year (2015-2017), meaning the need for more sophisticated sun protection products is higher than ever.2 As awareness increases around the importance of SPF and UVA ratings, this means that sun protection products need to follow current trends, meet strict guidelines in terms of high SPF, UVA protection and meet sensorial requirements. For the formulator, lots of factors must be taken into consideration. They not only face strict regulations to abide by which are different in each region, but the products must pass strict and expensive in vivo SPF and UVAPF tests whilst also taking into account the ethical and environmental implications of each product, all whilst keeping the sensory and the cost of the product desirable. This is where taking advantage of the synergistic effects of using a combination of organic and inorganic UV filters can help within a formulation.3

Inorganic UV filters are often referred to as physical UV filters due to their mode of skin protection. The most used inorganic UV filters are titanium dioxide (TiO2) and zinc oxide (ZnO), which are growing in popularity due to the known mildness, lack of skin penetration and other factors such as natural mineral origin and reef-safe claims.