Everyone knows that proper use of sunscreen can protect consumers from damage caused by ultraviolet radiation…Or do they?

The New York Chapter of the Society of Cosmetic Chemists (NYSCC) put sun protection in the spotlight during a one-day education event this month. “Sunscreen Formulations: Misconceptions & Future Directions for Innovation” occurred in Weehawken, NJ. The meeting was chaired and moderated by EMD’s Howard Epstein, PhD.

“Since covid, science has been abused; how we get information is not very accurate,” noted Epstein. “It is a growing problem.”

It’s a problem for science in general, and sunscreens in particular.

William Goodfellow, Exponent Inc., told attendees consumers encounter misinformation every day in various ways, including word-of-mouth, internet searches, social media and influencers. He noted that just as Summer 2024 was underway, some influencers began asking their followers, “is your sunscreen poisoning you?” Another tweeted, “we blame the sun for skin cancer, but should we blame our food?”

Goodfellow told attendees that statements such as these fill a vacuum—a vacuum that the industry must fill and respond in responsible journals.

“In the absence of our informed understanding of specific issues, the vacuum of information will be filled with uninformed information,” he explained.

Goodfellow noted that the publishing industry is dwindling; companies are going out of business and journals are expanding their scope. As a result, reviewers are not subject matter experts and manuscripts are not peer-reviewed.

“Journals and organizational press releases overstate things to be ‘above the fold,’” he charged.

Moreover, articles, blogs, podcasts, etc., often “live” on the internet for years.

“It is very difficult to remove bad science once it has been published, as well as information posted on social media,” added Goodfellow.

Misinformation v. Disinformation

Goodfellow said science communication is fraught with misinformation and disinformation. The former he described as unintentional false information, inaccurate information or just getting facts wrong. Misinformation may be caused by rushing studies to be first to publish, insufficient QA/QC of data before publication and repeating information without verification.

In contrast, disinformation involves intentional false information, knowingly inaccurate information and deliberately misstating facts. Reasons for circulating disinformation include:

• Designing studies to support pre-desired results;

• Knowingly posturing false information; and

• Promoting a political agenda not based on good science.

To help remedy the situation, Goodfellow said all work and outcomes should have adequate review to make sure that pitfalls can be viewed from numerous perspectives. He reminded attendees that the role of the scientist is to evaluate underlying data, evaluate source data, communicate correct information and uncertainties, evaluate source data and question everything!

“Otherwise, we will continue to see the public accept misinformation as ‘true’ because they don’t have the information to balance misinformation,” Goodfellow concluded.

Endocrine Disruptors

Daniela Fruth PhD of Merck Electronics detailed the complex world of endocrine disruptors, substances that, at certain levels, can interfere with endocrine or hormonal systems.

“It’s not just one test, it’s not just one answer when it comes to endocrine disruption,” she warned attendees. “There is a lot of misinformation and it is all very political.”

For example, the European Commission has identified vitamin D3 as an endocrine disruptor.

Rather, she urged the audience to consider the EATS modalities:

• Endocrine

• Androgen

• Thyroid

• Steroidogenesis

How are organic filters related to endocrine disruptors? They have been shown to interfere with EATS, according to the speaker.

EPA, Sunscreen & the Environment

Sandy Raimondo of the US Environmental Protection Agency (EPA) reviewed results of a 2022 Agency study conducted for the National Academy of Sciences for potential impacts of currently marketed sunscreens on the environment. After filters were detected in water samples from around the world and in the tissue of marine organisms, NAS recommended that the EPA conduct an ecological risk assessment for all currently marketed UV filters and any new ones that become available. Raimondo admitted that such monitoring does not provide robust representations of chemicals in the environment.

“With the present state of the science, the data just are not there,” he noted.

As a result, some compounds will be evaluated based on data for fewer than five species (most less than 10 species). In addition, the endpoints may not be ecologically relevant.

To improve its studies, EPA is asking for help. Data EPA would “love to have,” according to Raimondo, include:

• Quantitative Adverse outcome pathways (qAOPs);

• Quantitative linkages from molecular initiating event through population-level impact;

• Interspecies linkages;

• Pathways validated with lab studies;

• Species Sensitivity Distribution (SSD);

• Diverse taxa, multiple studies; and

• Identify most sensitive taxa;

That said, Raimondo pointed out that EPA does not regulate personal care products (or OTC drugs, for that matter).

Still, EPA’s Office of Research & Development has issued a notice on research funding opportunities regarding the ecological risk and impact of UV filters in sunscreens and aquatic ecosystems. To learn more, and to get involved, visit the EPA website at https://www.epa.gov/research-grants/research-funding-opportunities.

Designing Mineral-Based Sunscreens

FDA seeks more data on organic sunscreens. As reported in Happi, regulators are even calling for animal testing to ensure safety. What’s a formulator to do?

Jeroen van den Bosch, Uviva Technologies suggested designing mineral-based sunscreens—after all, FDA is seeking more data for either zinc oxide or titanium dioxide. He presented a design strategy to create zinc oxide-based products that consumers want to use. Historically, ZnO formulas are not aesthetically-pleasing due to large particle sizes. Formulas are less transparent and heavier on skin.

But these issues can be alleviated if formulators choose coated zinc oxide with regular particle shapes, according to van den Bosch. And when formulating with zinc oxide powder, van den Bosch recommended using a dedicated dispersing aid in an optimum amount and building the formulation in the proper order of addition:

            • Combine ester and dispersing aid;

            • Add ZnO while mixing and homogenize until smooth;

            • Combine with other oil phase ingredients; and

            • Combine oil and water phases.

“Particle size is important, but so is morphology,” concluded van den Bosch. “Dispersion is critical when you work with zinc oxide.

Richard Rigg, Vizor, explained why modifying the surface of zinc oxide is important to reduce whiteness, improve aesthetics and boost SPF.

But before he did that, he wondered aloud about the Environmental Working Group and its suncare product ratings.

“I am surprised that an organization with so little knowledge can be so damn powerful.”

Many in the audience would certainly agree with his statement.

Back to the subject of zinc oxide, the speaker admitted that zinc oxide is difficult to work with, as it involves making emulsions in three phases: oil, water and ZnO. To create an effective formula, he recommended, a three-step approach:

1. Choose the right starting particle, uncoated zinc oxide.
2. Identify the optimum surface treatment to add functional value such as higher SPF.
3. Select the right coating process.

“Most skin care chemists are lost when they can’t use Carbopol,” he charged. “Better to give sunscreen formulations to color cosmetic chemists!”

He concluded that surface modification is the only real tool available to chemists. As a result, formulation science is critical.

“What we found is that you can have an oil-in-water formulation (O/W) perform as well as a water-in-oil formulation (W/O). The trick is to have it invert on skin to water-in-oil. If a film is continuous, you have a better shot at getting a higher SPF…but make sure the formula inverts on skin.”

The Impact of UV and Visible Light on Skin

Süneco Technologies’ Ross Pearlman MD and Buu Duong MD reviewed skin damage caused by UV. They noted UVC (250nm) barely penetrates the epidermis. UVB (300nm) passes through the epidermis and into the dermis. UVA (350nm) passes deeply into the dermis and damages collagen and elastin production.

UVB exposure causes pre-mutagenic DNA lesions such as pyrimidine dimers. Actinic keratosis is one type of premalignant lesion, but there is only 0.1% chance of malignancy transformation with each actinic keratosis. However, the accumulation of these mutations increases skin cancer risk.

The speakers also reviewed blue light’s impact on skin. They noted blue light destroys epidermal and dermal structures, but admitted that researchers don’t understand how it induces melanogenesis. Pearlman told attendees that iron oxide is the only dependable way to protect against blue light-induced damage.

FDA Wants Sunscreen Permeation Test Results

FDA wants more sunscreen permeation tests. The Agency is calling for animal-based testing, a call that is getting rebuffed by animal rights groups, consumers and many fast-moving consumer goods companies. FDA’s Yang Yang MD didn’t wade into that controversy. Instead, he detailed in vitro studies to support Maximal Usage Trials (MUsT) for sunscreens.

Some history. In 2019, FDA proposed sunscreen regulation changes. In conducting in vitro studies, sunscreen active ingredients were detected in the bloodstream. In part II of its investigation, the FDA looked at the permeation in four different skin models (two human cadavers and two in vitro human skin cultures). Formulas contained varying levels of oxybenzone, avobenzone and octocrylene.

According to Yang, concerning permeation, in vitro human skin cultures and human cadaver skin responded in the same manner of oxybenzone permeation from sunscreen formulations. But Yang warned that human skin model performance may be formulation-dependent. Octocrylene was found to reduce permeation, and propylene glycol enhances penetration, but pH had no significant impact on the permeation of oxybenzone.

“To determine whether in vitro human skin cultures can be used as human skin surrogates for IVPT (in vitro permeation test), additional investigation using other topical drug products is needed,” he concluded.

Next, researchers looked at physiologically based pharmacokinetic (PBPK) models to predict dermal absorption of oxybenzone. They concluded that data may be used as a reference to pharmacokinetic endpoints of topical sunscreen products. Now, researchers are looking into different skin models for their potential in sunscreen IVPT. Furthermore, they are using a modeling approach to predict dermal absorption of sunscreen actives.

Environmental Risk Assessment

Carys Mitchelmore, University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory, detailed results of seawater and coral monitoring projects in Florida from 2019 to 2024. Presence of UV filters varied greatly due to site differences, sample variations and seasonal differences.

“Even within a few hours you get very different concentrations,” she noted. “Once people leave (the water), levels rapidly decrease. It’s very complicated. We need standardized analytical test procedures.”

Still, researchers found toxicity to be underestimated in static-renewal tests. Flow-through tests indicated higher toxicity (lower EC50 & LC50) than static-renewal tests in the chemicals studied.

Ratan Chaudhuri, Sytheon, detailed the benefits of incorporating acetyl zingerone (AZ) into suncare formulas. He maintained it is more effective at neutralizing reactive oxygen species than alpha-tocopherol or zingerone (ginger).

Built with a zingerone backbone, AZ is an antioxidant that helps reduce the burden of ROS by five distinct pathways:

• Select chelator;

• Enzyme inhibitor;

• Defense system modulator;

• Conventional antioxidant; and

• Physical quencher.

Chaudhuri said AZ reverses key biomarkers involved in aging and photoaging.

“The effects you get with AZ are far more effective than zingerone. In five years, the industry will be bragging about the benefits of AZ,” he predicted.

Chaudhuri was the final speaker at the NYSCC symposium, which was a well-received, sold-out event. Next up on the NYSCC schedule are a webinar, Embracing Global Beauty on June 27, and the annual golf outing on July 29. To learn more, visit www.nyscc.org