A Closer Look at Sunscreens: Insights, Innovations, and Inaccuracies

Experts weigh in on the current state of SPF and skin protection.

By Paul Winnington
 

Sunscreens. They are widely available, generally affordable, and easy to apply. They are proven effective for reducing risks of skin cancer and signs of photodamage. And they are also surprisingly controversial.

Media outlets, marketers of sunscreen “alternatives,” and consumer groups have all weighed in on the safety and efficacy of sunscreens, sometimes with misleading claims or false information. The result is a good deal of confusion and misinformation in the public sphere.

Doris Day, MD is used to fielding questions about the safety of sunscreens. “Patients question me on this on a daily basis,” she acknowledges. “My response is that sunscreen actives are FDA approved and that it’s a very rigorous process that takes years.”

When it comes to reports of sunscreen under-performance—a topic that gets a lot of ink but perhaps not so much critical assessment—the issue may be less about the sunscreen formulation and more about the practicality of sunscreen use. “The SPF on the label is decided based on standardized testing but is not a reflection of how it’s used in the general population,” Dr. Day notes, “so I recommend a higher SPF when possible.”

Some patients consider SPF rating as a sort of time rating of sunscreen protection. While this concept is technically rooted in the FDA-approved SPF testing process, it’s not entirely accurate. Any sunscreen product requires re-application, and each label provides instruction on frequency of re-application. Additionally, patients still may not recognize that SPF assesses UVB filtering only. It does not assess UVA filtering.

Dina Anderson, MD confronts patient confusion about SPF on a consistent basis. “Patients tell me, ‘I wore SPF 70 and reapplied and still got freckling and color.’ I explain that SPF only measures UVB and at an SPF of 30, 95% of UVB is blocked, but usually not UVA (in most chemical formulations). That is why melasma comes back in summer for women who use these types of chemical sunscreens.”

There is evidence that higher SPFs offer enhanced protection relative to lower SPF products in “real world” settings. In other words, if a patient isn’t going to apply enough sunscreen or re-apply it frequently enough, a higher SPF product may provide more protection over a greater period of time, than a lower SPF product would.

For Sandra Marchese Johnson, MD, advising patients on sunscreen selection remains just one aspect of the UV avoidance conversation. “Sunscreens should be used as part of your sun smart behavior,” she admonishes patients. “Avoid peak hours, seek shade, wear sun protective clothing, etc. Sunscreen reapplied every two hours is effective when used with other sun smart behaviors.”

Ingredients in the Crosshairs

In recent media coverage of sunscreens, there has been continuous questioning of sunscreen ingredient safety. The Environmental Working Group (EWG), whose annual sunscreen assessment is due this spring, has been a prominent opponent of certain sunscreen ingredients, especially oxybenzone. According to EWG, “Laboratory studies indicate that some chemical UV filters may mimic hormones.” Detractors argue that chemical sunscreens may even be linked to cancer.

“Due to a lot of false information relayed on the Internet/social media, many patients are concerned about sunscreen ‘causing cancer’ or being more harmful than beneficial,” notes West Hollywood dermatologist Nancy Samolitis, MD.

Dermatologists and sunscreen formulators have for years challenged such assertions. While there appears to be some evidence of a hormone mimicking effect for high doses of certain sunscreens in murine models, such effect has not been documented in humans. It is not established that sunscreens actually enter the blood stream at appreciable levels.

San Antonio’s Vivian Bucay, MD reassures patients about sunscreen safety by pointing out that formulations in the US are regulated by the FDA, which assesses safety as well as efficacy. “I also tell them that there are multiple published studies proving that sunscreens can prevent skin cancer but that there is not a single study proving that sunscreens cause skin cancer,” she adds.

Dr. Samolitis addresses the issue of paradoxical over-exposure, as well as the problem of sunscreen misuse. “I explain to patients that sunscreens have been shown to be beneficial in reducing physical signs of sun damage and risk of skin cancer; however, it is well known that people often use sunscreen incorrectly, leading to decreased efficacy and a false sense of protection,” she says.

Rather than try to convince patients who are skeptical about sunscreen chemicals, dermatologists can offer alternatives. In fact, Dr. Anderson says that her preferred sunscreen is a physical one. “The best and safest ingredient is zinc oxide, hands down,” she says. “It is safe enough for a newborn baby’s bottom, and this inert, physical block is the best at blocking UVA, where most chemical formulations fall short.”

An important distinction in media reporting around sunscreen is the issue of “reactions” to sunscreen ingredients. Especially if an individual has had a personal experience of developing a skin rash after using a sunscreen, he or she may view the products as inherently harsh or “unsafe.” However, this is clearly not the case.

“I point out that currently available sunscreens use ingredients that are generally recognized as safe. While individuals sometimes have reactions to certain sunscreens, the overall risk of having a problem with sunscreens is low, especially relative to the amount that is being used,” says Todd Schlesinger, MD. “The efficacy has been tested in independent laboratories and vetted by the FDA, which has resulted in updated labeling guidelines.”

Explaining to patients the nature of allergic contact dermatitis and pointing out that the reaction is an individual response may help relieve anxiety associated with sunscreens as a class.

Physical Fitness

For a variety of reasons, dermatologists seem to have a slight preference for physical sunscreens over chemical ones. “Physical and chemical both work, but my preference is physical—zinc oxide and titanium dioxide—because of broader coverage and greater stability, as well as a lower incidence of sensitivity to their ingredients,” Dr. Bucay says.

Dr. Schlesinger similarly prefers physical or inorganic sunscreens, also noting that they protect against a wider spectrum of the ultraviolet light range. “Physical blockers sit on the surface of the skin and are washed off easily, so they are better when the skin stays dry,” he says. But chemical sunscreens may have an important role. “Chemical, aka organic, sunscreens absorb into the proteins of the skin, so are good at protecting the skin, even if it gets wet from swimming or sweat,” he adds. Dr. Schlesinger tells patients all sunscreens should be reapplied frequently for the best protection.

“I personally prefer physical sunscreens and even lean toward tinted sunscreens that contain zinc oxide and titanium dioxide,” Dr. Samolitis echoes. “It has recently been verified that tinted sunscreens (containing iron oxide) have better protection against all visible light including indoor light and ‘screen light’ from devices, which may be contributing to conditions such as melasma.”

DATE CHECK

FDA regulations require all sunscreens and other nonprescription drugs to have an expiration date unless stability testing conducted by the manufacturer has shown that the product will remain stable for at least three years. That means a sunscreen product that doesn’t have an expiration date should be considered expired three years after purchase.

—FDA.gov

Another benefit of physical sunscreens? They may “stay in place” better, especially in the period immediately after application. Dr. Johnson explains, “I personally like physical blockers because it does not get into my eyes. Sunscreen can burn when it gets into my eyes.”

“With newer methods of micronizing zinc and titanium particles, the mineral sunscreens often are more cosmetically elegant,” Dr. Samolitis says. “Many of the chemical sunscreens often have an offending odor, oily texture, or cause stinging/burning of eyes with sweating.”

Given the purported benefits of physical sunscreens, it may come as a surprise to dermatologists that when Consumer Reports evaluated sunscreens last year and published its ratings, “None of the mineral sunscreens in our tests…did well enough to make our list of recommendations.”

The Personal Care Products Council, the leading national trade association representing the global cosmetic and personal care products industry, took issue with Consumer Reports’ sunscreen assessment process, stating, “It appears that their testing methods are not consistent with those used by the US Food & Drug Administration (FDA). Therefore, their testing methods are not the same as those required of product manufacturers to assign the SPF designation…We do, however, caution consumers that the results of the Consumer Reports testing cannot be directly compared to a label claim.”

In announcing their ratings, Consumer Reports provided this description of their assessment process, which seems to parallel the testing process required by the FDA:

To check for UVB protection, a standard amount of each sunscreen is applied to six places on our panelists’ backs. Then they soak in a tub of water. Afterward, each of those areas is exposed to six intensities of UVB light from a sun simulator for a set time. About a day later, the six spots are examined for redness. The resulting UVB protection ratings reflect each product’s actual effectiveness after water immersion and are based on an average of our results for each sunscreen.

The UVA test we use allows us to differentiate the degree of UVA protection among sunscreens.

To test for UVA, we smear sunscreen onto plastic plates and pass UV light through and measure the amount of UVA and UVB rays that are absorbed. That information is then used to calculate our UVA score.

Dermatologists and product marketers maintain that physical-based formulations on the market can be trusted, and should perform in a manner consitent with their SPF rating. Formulators from Pierre Fabre Dermo-Cosmétique Research and Development/Product Development Division addressed questions about formulating with physical sunscreens. They say that, “It’s not just a question of concentration but the right balance between tolerance, effectiveness and compliance.” They indicate that SPF rating remains the best and most reliable tool for assessing a formulation. “For the consumer, the SPF of a sunscreen is a good information of how well it protects the skin from sunburn.” (Look for more insights on sunscreen development from formulators in an upcoming edition of Practical Dermatology® magazine.)

As Dr. Johnson notes, “’I tell my patients that any product of SPF 30 or higher they like is fine. There are many options. They need to apply enough to get full coverage and reapply every two hours.”

“The majority of my patients are put on a micronized, zinc based block with a slight tint. Tizo is 16% zinc and very elegant without odor or a greasy feel and my preferred brand, although Young also offers a similar formulation with a lower concentration of zinc but more shades for darker skin types,” says Dr. Anderson. “They rub in well and do not leave a ‘ghostly hue’ that happens with many OTC zinc based sunscreens. I try to stay away from chemical formulations as they are not effective UVA blockers.”

Tinted formulations may appeal to patients with active skin diseases, including acne. “My oldest is 14. She worries about things that are put on her skin that cause acne. I have taught her all about things that say non-comedogenic,” says Joel L. Cohen, MD. “Now, there is an Elta Clear that actually has a tint too—it comes in regular clear or tinted clear. This is specifically formulated and labeled as non-comedogenic, but the fact that it has a tint helps hide some of the post inflammatory redness from acne. So it’s a double-whammy.”

A Bevy of Vehicle Options

Recent years have witnessed the emergence of various sunscreen formulation vehicle types, including powders, sticks, and towelettes (See table for FDA-approved formulation types). These offer consumers/patients enhanced flexibility and convenience, hopefully bolstering adherence. “Vehicles are a matter of personal preference,” Dr. Bucay says. “What’s important is to apply enough sunscreen and to reapply frequently.”

Dr. Johnson urges patients to, “Try to use a sunscreen that is cosmetically elegant to you.”

Dr. Schlesinger takes a similar approach. “The best kind of sunscreen product is the one that gets used,” he says. “Whatever the user prefers and will use on a regular basis would be the one I would be happiest with.”

Dr. Day also notes that the most important consideration is that a patient actually use a sunscreen. However, she does find certain vehicles have benefits. “I like gels for those who are active or acne-prone and for men. They tend to blend in quickly and not feel sticky on the skin or run into the eyes in those who are active,” she says. “Sticks are great for sensitive areas like the nose and even for the scalp.”

“Sticks are great for lips and around the eyes, because the sunscreen adheres better and won’t run into the eyes or come off the lips as easily,” Dr. Bucay offers.

Both Dr. Day and Dr. Bucay favor powders for regular re-applications throughout the day for women who wear makeup. Solid creams are also good for this application, Dr. Day says.

“I personally like a cream for daily use and a powder to reapply when outdoors running or sweating. I like TD&R SPF 50 Daily,” offers Dr. Johnson.

Sprays are good for large surface areas like the back, chest, and legs or for hairy areas, the dermatologists we spoke with say. There are physical-based sprays on the market now. “For the body, I prefer physical-based sprays (Elta) and tinted zinc or titanium oxide-based sticks for areas where there are wounds or surgical scars that are still healing,” Dr. Anderson says.

When it comes to sprays and certain other vehicles, patients may need reminders on proper use. “I remind patients that they still need to rub in the sunscreen to get adequate protection, especially if it’s a spray, to avoid ‘skip areas,” Dr. Samolitis advises.

A Matter of Fact

Dermatologists may find UV safety education frustrating, especially as misinformation continues to accumulate. However, it is important to arm patients with facts and direct them to the best sunscreen for them. “I typically will recommend a list of certain brands to patients and suggest that they choose the vehicle depending on their personal preference,” Dr. Samolitis says.

As noted multiple times by experts, sunscreens only work when they are used properly. And they are just one part of UV safety.

 

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About Practical Dermatology

Practical Dermatology is the monthly publication that provides coverage of medical care, cosmetic advancements, and practice management for clinicians in the field. With straight-forward, how-to advice from experts in various fields, we strive to enhance quality of care and improve the daily operation of dermatology practices.