Eco-conscious sun protection

COSSMA: What are the most important product trends in sun care at present?

Stéphanie Acker, Senior Technical Manager Sun Care, BASF: Major market trends include for example improved protection across the entire UVA and UVB spectrum, additional protection against visible blue light as well as and lighter, more pleasant formulations. 

We are increasingly seeing and addressing another trend: consumer demand for products with improved environmental compatibility and, more generally, for more sustainable products is on the rise. 

We expect this trend to continue or even accelerate since public discussion is focused on environmental issues. These  include as adverse effects on corals and marine life, endocrine disruption, and bioaccumulation.

Do sun care and sustainability go together?

Absolutely – it’s all a matter of using and balancing the right ingredients. To assess the environmental impact of the UV filters used in sunscreen formulations, our company has developed the EcoSun Pass. This methodology was created to provide a tool for assessing UV filters more holistically. It is based on internationally recognised criteria and takes into account eight different parameters. 

From what we know, it is the first scientifically sound and transparent system to rank and thus potentially improve the environmental impact of a given formulation available on the market. It is based on the latest scientific findings, which improves regulatory acceptance. 

Which criteria are covered by your assessment tool? 

The eight criteria covered by our evaluation method include bioaccumulation, biodegradation and Log Pow, endocrine suspicion, toxicity to terrestrial organisms, toxicity to sediment-dwelling organisms, and acute and chronic aquatic toxicity, i.e. the intrinsic capability of a substance to cause damage to aquatic organisms after short-term or long-term exposure. Each substance is assigned a specific environmental ranking.

All eco-ranked substances in a given formulation are then rated on an open-ended scale, starting at zero for ingredients with the worst possible performance. 

We created an algorithm to calculate the effect of a sunscreen formulation on the environment that takes the eight parameters into account for each UV filter. The EcoSun Pass value for any given formulation is normalised for its sun protection factor to prevent sunscreens being rated as poor because of their high efficacy and filter concentration. The higher the EcoSun Pass value for a formulation, the more environmentally friendly it is.  

How does this tool help manufacturers formulate sunscreens that meet the demands of eco-conscious consumers?

It enables us to advise formulators as early as possible in the development stage on which UV filter combinations are best suited for their application – in the interests of both the consumer and the environment. As well as considering environmental factors for individual UV filters, it provides a comprehensive environmental evaluation for the entire filter system within a sunscreen product. This enables our customers to evaluate their sunscreens based on all the relevant environmental aspects and allows for the eco-friendliest consumer product to be brought onto the market. 

The methodology does not apply only to our company’s products; it works entirely independently of our product portfolio. All widely-used UV filters are assessed transparently, regardless of the supplier. This means that potential improvements to the UV filter mixture may or may not involve our ingredients.

One approach to formulating sunscreens with improved environmental compatibility is to select the most efficient UV filters with better environmental profiles and use the lowest possible concentrations. This also makes formulations as light as possible without compromising performance.

One widespread fear is that nano particles easily penetrate the skin and cause undesirable effects. 

However, percutaneous absorption depends on several properties, including chemical structure, molecular weight, solubility and polarity, as well as melting point. Both the organic and inorganic nano filters in our portfolio are very unlikely to penetrate the skin. With particle sizes starting between 20 and 500 nanometers, they are vastly bigger than other common UV filters which are not classified as nano because they are soluble in oil or water. In comparison to other cosmetic ingredients, nano particles are quite large.

Another fear centres on the acute and chronic inhalation toxicity of spray applications. Both acute and chronic inhalation toxicity tests are required by the EU Scientific Committee on Consumer Safety (SCCS) to confirm safety in spray applications. With a ban on animal tests in place, it is virtually impossible to prove products are harmless regardless of filter size. For some widely-used UV filters, whether nano or not, only acute inhalation tests are available. Getting approval for spray applications would be impossible today. 

Despite their vastly different properties, consumers are becoming increasingly wary of all nano particles – a trend driven by the tendency of consumer organisations and journalists to denigrate products containing nano particles. When consumers spot the mandatory (nano) indication in the ingredients list of any particular product, they are more likely to leave it on the shelf and buy another product instead. 

What are the advantages of nano-sized UV filters?

For particulate UV filters such as MBBT, TBPT, ZnO and TiO2, we can prove that efficacy increases with decreasing particle size – and at the same time, smaller particles have a reduced white-painting effect. This means that nanoparticles allow us to formulate more effective, lighter, and more transparent sunscreens.

Moreover, nanoparticles have a very beneficial triple effect: they reflect and scatter light due to their particulate nature. The structure of organic particles allows for the highest absorption which makes them more efficient than inorganic particles. 

What would forgoing nanoparticles mean for sunscreen manufacturers?

Nano-sized filters are highly efficient and do not need to be dissolved in water or oil. Replacing them with oil-soluble filters would require more emollients, making formulations heavier and oilier. 

It would also become more difficult to formulate highly effective formulations generally, and formulations would be harder to stabilise.