LIFESTYLE


Formulating: The ultimate balancing act


Lou Graydon - Aston Cosmetics, UK


In the age of misinformation, there is a myriad of articles, blogs and social media posts claiming that cosmetic ingredient ‘X’ is terrible but ‘Y’ is perfect. Cosmetic scientists around the globe baulk at these claims as very rarely is anything so black and white, particularly when it comes to skin care. In fact, an individual’s skin care needs


constantly change depending on diet, hormones and even the time of year.1


What skin actually


requires is a balance of a variety of ingredients to target those needs – there is no universal serum that will give everyone perfect skin. Cosmetic formulations themselves are


mixtures of different materials carefully balanced to provide the best stability, aesthetics and texture possible. Arguably the most important category of ingredients for personal care is emulsifiers. However, when formulating a cosmetics product there is a lot more to consider than just the ingredients. Sustainability and environmental impact are


at the top of nearly everyone’s agenda, with many claims being made about eco-friendly practices, but in reality, the issues we face are enormously complex. As with skin care, there is no single method of reducing environmental impact and, in many cases, choosing to focus on one area of sustainability can have consequences elsewhere. This article discusses the conflicts,


compromises and trade-offs that formulators encounter every day, whether related to ingredient performance, naturality, sustainability or consumer perception.


Sun care One of the most discussed topics over the last few years has been sunscreens and, with around 70% of consumers using SPF as part of their daily skin care routine2


, this is set to


become a mainstay. The most pressing issue regarding sunscreens is the effect on coral reefs of organic UV filters.3


creating an excited-state molecule which will eventually degrade and lose its absorption ability if it is unable to return to the original ground state.4 Although there is significant evidence


that coral damage is mostly caused by sustained elevated temperatures resulting from global warming5,6


, several legislators


have begun to ban some organic UV filters, including benzophenone-3 and ethylhexyl methoxycinnamate, in response to a handful


www.personalcaremagazine.com These absorb UV radiation,


Figure 1: To be launched at SCS Formulate, Deluxe Detox Solid Shampoo contains synthetic fluorphlogopite


of studies which concluded that they are toxic to corals.7,8


The data available is limited,


with significant data gaps and flaws in the methodology used. In order for any future data to be reliably used


to inform policies, a standardised method for determining coral toxicity must be developed, ensuring all solvents, species and tests used are appropriate for the research being conducted. This would allow toxicologists around the world to replicate and confirm the findings, providing a reliable base for decision making. However, with media attention, there has


been a rapid increase in public and political interest on the topic5


, resulting in a trend


towards inorganic UV filters – namely titanium dioxide (TiO2


) and zinc oxide (ZnO). These


are mineral-based, and there is a common misconception that their UV filter properties are mostly a result of reflecting, refracting and scattering the radiation. In reality, the majority of UV is absorbed by the compounds, with only a small amount being scattered and reflected.4 While the shift to inorganic filters might be


beneficial for our oceans, there is evidence that ZnO and TiO2


are semiconductor materials,


which are photo-activated when exposed to UV light and when this occurs, the materials generate radical species such as •OH, which are highly oxidising.9 Studies have shown that these materials,


even nanoparticles, do not penetrate the stratum corneum and therefore have no effect on viable cells. However, in order to reduce the risk, it is important for formulators to use surface-treated inorganic sunscreens, which


helps to reduce the photoactivity. The biggest challenge that formulators face


with inorganic sunscreens is their opacity. It is notoriously difficult to formulate a stable, high SPF, inorganic sunscreen product which is suitable for all skin tones. Inorganic filters are white solids, which inevitably cause a white cast on skin when used at the levels needed to obtain a high SPF rating. They also turn milky on contact with


water and sweat, and these effects are much more noticeable on dark skin tones. There are a few ways to reduce this effect, with the most common being to create a tinted SPF formulation, which helps to cover the white appearance. This works to a certain extent, but if the levels of inorganic filters are too high, the product can appear ashy on skin, even with the addition of other pigments. Another solution is to use nano-sized


inorganic sunscreens. These are much less whitening and also provide higher SPF, and so can be used at lower levels. However, if the reason for using nano-materials is to avoid organic SPF filters and the risk of any potential damage to coral reefs, it is necessary to consider the bioaccumulation of nano-TiO2 oceans for the same reason.10,11


in the Again, the data


here is limited and it is hard to draw definitive conclusions, but based on these findings, many brands have chosen to avoid nano UV filters. As SPF products are a vital part of a skin


care routine, the only option left is to reduce the impact of the UV filters on the environment through reducing rather than eliminating their usage. This can be achieved by creating hybrid sunscreens; balancing the levels of both organic and inorganic filters within a product to achieve a high SPF product with minimal whitening. Using both types of UV filter also gives a synergistic effect due to the light scattering ability of the inorganic UV filters, which can help to reduce usage levels even further.12-14


Naturals vs synthetics Whichever direction a brand chooses to take, the products they create must be functional and UV filters are not the only ingredients that have an influence on the SPF rating. Film-formers are extremely important to ensure the product stays functional and is not removed from the skin by sweat, water or transfer to clothes. Synthetic film-formers are frequently the


best choice for performance, but their lack of biodegradability can also raise environmental


November 2021 PERSONAL CARE


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