Testing our sunscreens

Sunscreens play an important role in public health and can reduce the risk of sunburn and skin cancer when used appropriately. We can't joke with their effectiveness and safety, and that's why we put them through various tests.

You should never have an uneasy feeling if you’ve bought something from Lush,” says Lush co-founder Mark Constantine. "We are offering products that consider the long-term health of your skin beyond its appearance. Reaching the right decision about products like sunscreen and hair dye takes a lot of discussion and we have to be open to changing our mind."

Tests on finished products - Lush testers panel

Back in the late 80s, when Lush was still a mail-order brand called Cosmetics To Go, our very first suncare range was tested on volunteers (including Lush co-founder Rowena Bird) as they climbed Kilimanjaro. While it was a particularly brave (if not hardcore) in situ testing situation, we're doing things a little differently today.

Lush’s product testing coordinator Jet Shears explains: “Every newly created product is thoroughly tested to ensure it is effective and safe to use. Firstly, the product inventor will use the product themselves. When they are satisfied, the product is then upscaled in our R&D facility and a larger quantity is made ready for our testing panel.The panel counts around 350 volunteer testers, all completely independent of Lush, with a variety of skin types, skin tones and concerns. They are sent products and asked to use them for a relevant period of time, usually three to four weeks, after which they fill out a feedback form.

Because some sunscreens can leave a white cast on darker skin tones, we also sought feedback from people of colour who work within the business. These testers gave us important feedback on which products worked for different skin tones and where gaps in the range needed to be filled. 

Tests on finished products - SPF and UVA

All sunscreen products must also be tested to assess the protection they offer. In our case, it's been done by an animal-free facility in France. Protection assessment is something you’ve seen on most sunscreen tubes and packages: it's the SPF (Sun Protection Factor) rank and/or the UVA logo. SPF testing measures the depth of protection, while UVA testing looks at the breadth of protection across the UVR spectrum.

SPF levels are presented as numbers. The higher the number, the more protection you can expect if you apply the product at the same thickness it was tested (2mg per cm2 of skin). While SPF ratings are commonly interpreted as a way to extend your time in the sun without damage, it is more accurate to think of them as a ranking system because many of us apply less sunscreen than manufacturers test. An SPF15 product applied at 2mg per cm2 of skin will give you 1/15th of the UVB exposure you would otherwise receive.

Finally, the UVA logo tells you if your sunscreen also offers good protection from UVA, a type of sunlight that leaves few visible marks but can still cause damage to the body. In the EU, UVA must be over a third of the SPF value to allow a brand to display the icon on a sunscreen.

Tests on individual ingredients - Toxicity, sensitivity and safety

Since 2014, we have been using the same three organic UV filters, sunscreen agents that absorb UV rays and protect your skin from them. Octylmethoxycinnamate (OMC), octocrylene (OC) and butyl methoxydibenzoylmethane (BMBM) were selected by our inventors for their long history of use and a large amount of test data available on them. However, in recent decades they have been described as controversial by some with questioning their long-term safety, particularly for skin sensitisation and cancer risks. Listening to these concerns, and being aware that all available data came from animal testing anyway, Lush founders decided to pull the range from sales in 2020 to take a closer look at these ingredients.

They passed the hot potato to Dr Chloé Raffalli, Lush's toxicologist. She is in charge of evaluating products' safety before they are sold and of providing animal-free data (available or commissioned by Lush from partner laboratories). “Most cosmetic companies still rely on historical animal data,” she says, “despite the piling evidence against animal testing as a respectable, satisfactory science that can protect consumers from harmful ingredients.”

In vitro testing with XCellR8

To assess our suncare products' safety, Chloé commissioned two tests from XCellR8, a lab we’ve been working with for years. "XCellR8 is the first lab that is 100% animal-free and uses only human by-products, giving us data that is ethically sourced and far more relevant to human health," Chloé explains. 

Genotoxicity test: Our ingredients have been tested on human cells and on reconstructed human epidermis tissue using the BlueScreen™ test. The laboratory faithfully reproduces the exposure of our organisms to certain substances. It even imitates metabolism activity with enzymes (because our body can actually be pretty good at eliminating unwanted substances). The lab is able to test for different types of genotoxins: clastogens, which damage chromosomes, aneugens, which can alter the number of chromosomes, and mutagens, which alter DNA. A genotoxic substance damages the genetic material of cells (DNA), and these changes can potentially lead to cancer, which is why genotoxicity testing is so important.

Skin sensitisation: Repeated exposure to an allergenic substance can cause allergic reactions in some people. The product may seem okay at first, but once you get sensitised, it's a lifelong condition that will show up every time you use the substance. This is why sensitisation is an important data to consider when assessing the use or the concentration of an ingredient in a cosmetic product. A 'two out of three' method of testing is used. Two to three tests are performed; if two fail, the ingredient is considered sensitising. XCellR8 did three different tests: the Direct Peptide Reactivity Assay (DPRA), KeratinoSens and h-CLAT. They cover a broad range of reactions, from covalent protein binding to keratinocyte activation and dendritic cell activation. The last step of this assessment is to establish a Dermal Sensitisation Threshold (DST), which helps determine safe and risky quantities. A low DST score means that even if a product is labelled 'sensitising' by previous tests, it is still not likely to cause adverse allergic reactions if used under a certain level.

Internal safety assessment

Once equipped with XCellR8 results, Chloé Raffalli conducted a systemic toxicity review, the final touch before returning to the inventors with a safety assessment.

Systemic toxicity refers to effects that occur at a distance from the site of application. For instance, cosmetics applied to the skin may affect other organs after entering the bloodstream. This high-tier hazard endpoint needs to be assessed in different steps.

To evaluate consumer exposure, a Systemic Exposure Dose (SED) of the ingredient is calculated. The SED is the amount expected to enter the bloodstream per kg of body weight daily. It is calculated with many parameters in mind, mainly linked to the product application (method, quantity, frequency and surface involved), the average skin absorption rate, the average weight of the exposed population and the ingredient concentration in the finished product. In the case of sunscreen, we wanted to ensure the ingredients were safe for children over three years old. Therefore, we considered lower body weight to calculate the systemic exposure dose compared to adults.

Considering SED and data from historical use, the systemic effect of the ingredients was assessed, and their safety for people above three years old could be proved. This led to the decision of re-launching our suncare range with confidence.

"The information provided to us through the work of XCellR8 has given us a guide to the levels of sunscreen we can use. This means we can now be confident that we are offering our customers suncare products that are good for their 100-year lives." Helen Ambrosen

Domovská stránka - Testing our sunscreens