Sunscreen Sensory

And the effects of product layering

Here Comes the Sun

The world is finally reopening, and what better time than the summer!? As we rush outside to soak in all the Vitamin D we missed in 2020, let’s not forget to apply sunscreen. We may have skipped this product in our daily skincare routines last year, but we surely do not want to burn in our newfound freedom! Sunburns are typically due to poor application of hard-to-reach areas, forgetting to reapply, and poor sensory. And while the first two reasons can be resolved by personal accountability or a loyal partner-in-crime, the third is up to science, which Gattefossé formulation and sensory experts can surely address.

 

In 2019, Gattefossé conducted a study to evaluate the impacts of the composition and texture on the remanence of sunscreens during the day. We found that vegetable wax derivatives could improve the durability of the protective UV film and that W/O emulsions delivered longer protection than O/W ones. (1) Though the results were quite informative, the study was performed on bare skin, knowing very well that a typical, daily beauty routine includes layers of products. And so, in a more recent study, we examined the effects of product layering on the sunscreen sensory, durability, and ease of rinsing. Let’s explore the methodology and the results so that you’re ready for summer 2021! 

 

The Methodology  

 

We performed seven tests of different product layer combinations, with the same sunscreen formula for each – an O/W emulsion containing a blend of organic UVA filters. 

                                                       

Using a UV camera, with a captor sensitive to UVA,  we were able to view and track the behavior of the UV protective film and ultimately rank the sunscreen durability, for each test.  We also used an auricular repositioning system to ensure the proper placement of volunteers to capture consistent images of UV absorption. Next, we performed an image acquisition with our UV camera at four time-points: before application of the sunscreen on bare skin (T-1), after application of the sunscreen (T0), 4h after application (T4), and after washing the skin with a cleansing gel (T4+W). We measured a specific parameter to quantify the remanence of the sunscreen, which correlates to its durability and its rinse-off ability. 

 

                               

 

As for evaluating sensory, we used sensory analysis with our in-house expert panel to evaluate the sunscreen layer, focusing on eight different sensory criteria, during the application, and after absorption.

 

The Results 

 

When considering the most durable and most easy-to-rinse products, the answer was clear. A suncare product applied on top of an O/W moisturizer containing a film former performed better than all other product combinations and better than the sunscreen alone.   

And when it comes to the sensory of the sunscreen, let’s break it down by category of layer combinations:

  • When applying suncare on top of a moisturizer, the suncare product is greasier, shinier, and tackier, and more spreadable than when applying suncare alone. 
  • When adding a film former to the moisturizer only, the residual film, greasiness, and soft after-feel are improved, while the tacky after-feel gets worse.
  • When there is a film former in both the sunscreen and moisturizer, the residual film and greasiness are surprisingly lower, despite the higher tacky after-feel. 

 

Though it is impossible to draw generalities from this study, the findings could still be interesting for future product development. However, you may need to find out which performance properties are most valued by your consumers. Do they prefer a sun care product that is able to be washed off easily or one that has a better water resistance? The methodology we used could also be beneficial for brands, alongside their consumer tests, to aid in their development of efficient product combinations for improved sensory and UV protection.
 
 
For a more in-depth look at this study, join us on July 29th, 11:30 am EST for our Sunscreen Sensory Webinar!
 
 
 
 
(1) Hubiche, V. et al. (2019) The Camera Nevers Lies, C&T vol134 N°4, 23-32