So many questions. So little time.

By Andrea Niermeier, April 1, 2023

Aisles of products, numerous social media top 10 lists, and abundant information on the internet: Consumers can be quickly overwhelmed with sunscreen questions related to types, usage, and safety — coming to their dermatologist to seek clarity. While most dermatologists could spend hours on the subject, they unfortunately don’t have the time. This month, DermWorld asked dermatologists to share their bite-sized responses to patients’ frequently asked questions about sunscreen.

Q: Who needs sunscreen? Why do I need sunscreen?

A: According to Kanade Shinkai, MD, PhD, FAAD, professor of clinical dermatology at the University of California San Francisco Department of Dermatology, one of the most important things for patients to understand about sunscreen is that it is part of a program of photoprotection from ultraviolet (UV) radiation from the sun that also includes sun-protective clothing, hats, sunglasses, shade. “We know that UV radiation can cause skin cancer and that skin cancer is the most common cancer in the United States, affecting over three million people a year.”

While we know that non-melanoma skin cancers occur more frequently in fair-skinned individuals, darker-skinned individuals are still at risk. Tasneem Mohammad, MD, FAAD, staff physician in the Department of Dermatology at Henry Ford Health Systems, explained that helping patients with skin of color understand that sunscreen can also help with prevention of pigmentary disorders as well as photoaging is crucial. “I help my patients understand that sunscreen can do different things for different populations but that it can do something for all populations.”

Q: What type of sunscreen should I use?

A: The American Academy of Dermatology currently recommends a broad spectrum, water-resistant sunscreen that is SPF 30 or higher. Ultimately, when helping a patient choose a sunscreen, Iltefat Hamzavi, MD, FAAD, senior staff physician in the Department of Dermatology at Henry Ford Hospital, suggests that the most important quality is wearability. “Knowing your skin situation and skin type determine what kind of sunscreen you pick. Not all sunscreens are appropriate for all populations. However, if you are not actually going to wear a sunscreen product because of color or formulation, forget about using that type of sunscreen and go for one you will use.”

Dr. Shinkai likes to start by asking patients about their sunscreen habits and barriers to sunscreen use. “Patients often tell me a lot of things that are quite insightful and offer a lot of opportunities to explore all of the sunscreen options.” Dr. Mohammad added that patients often imagine a beachgoer with a white triangle on the nose or have had negative experiences with thick, greasy, or uncomfortable sunscreens, making them apprehensive. Some patients may complain about the way a sunscreen interacts with their makeup, creates a white cast, or interferes with the hair on their body. For others, cost is a barrier.

Responding to these concerns, Dr. Mohammad reminds patients about the variety of sunscreens available, including lotions, creams, gels, sticks, powders, and sprays. Gels may be recommended to patients with beards or those concerned about body hair, and powders can work well for the scalp. For patients with skin of color, a variety of micronized mineral and chemical sunscreen filters exist. “Really try to explore the barriers to find the opportunities,” Dr. Shinkai suggested.

Dr. Hamzavi echoed this sentiment. “We can customize a sunscreen plan based on patients’ formulation, SPF, and spectrum of photoprotection needs. That requires us to offer something. We can’t just say ‘try whatever you like’. We have to tell patients, ‘This is your skin type, your habits, and your preferences — try this sunscreen.’”

Q: When should I use sunscreen? Do I need to wear it every day or just on sunny days?

A: When speaking to patients about sunscreen use, emphasizing a daily routine is helpful. Dr. Mohammad recommends connecting sunscreen application to another routine such as brushing teeth, getting out of the shower, applying moisturizer, or putting on makeup. Applying sunscreen during these times often provides the recommended 15 minutes before photo exposure, she noted.

Helping patients tailor their sunscreen routine to a variety of situations is also important. Dr. Shinkai commented that wearing moisturizers, makeup, or setting powders with adequate sunscreen components or UV filters for photoprotection may be a reasonable option for a patient heading into the office. When that person later decides to go for a jog during peak hours of the day, that’s when to encourage a water-resistant sports sunscreen. “These are the practical elements that I really try to encourage patients to explore — customizing the type of sunscreen that they should use and when,” Dr. Shinkai added.

Q: How much sunscreen should I use, and how often should I apply it?

A: Realistically, people only apply half to a quarter of the amount of sunscreen that they should, according to Drs. Hamzavi, Mohammad, and Shinkai. Sharing with patients that sunscreen testing in labs is done at a concentration of 2 milligrams per centimeter squared and explaining what that looks like may help patients understand that their actual SPF coverage may not be what they think it is.

While packaging usually recommends reapplication every one-and-a-half to two hours, again Dr. Mohammad urges using a common-sense approach with patients. If the plan for the day is taking a 15-minute walk in the morning or going out to get coffee, applying sunscreen once a day in the morning feels doable to patients. When a person heads to the beach, works outdoors, or sweats a lot, that’s when emphasizing frequent reapplication is necessary.

Dr. Mohammad also suggests that sunscreen type should be considered when speaking to a patient about application. For example, patients can often tell if a cream sunscreen has been applied evenly. However, patients who use spray or powder sunscreen filters may think they have gotten their whole body, but realistically the wind has wafted away 90% of the product, leading to uneven or inadequate coverage. An appropriate recommendation to patients is to spray the product directly into their hands and rub it over the whole body.

Q: Broad-spectrum sunscreens protect against both UVA and UVB rays. What is the difference between the rays?

A: Traditionally, dermatologists know that UVA rays are often thought of as the culprit for aging of the skin and UVB rays as more responsible for sunburn. However, visible light is worth discussing with patients as it also has effects on the skin, including pigmentation on darker-skinned individuals and increased inflammatory markers on lighter-skinned populations, Dr. Mohammad noted.

While most sunscreens sold for sun protection these days are labeled “broad spectrum,” covering both UVA and UVB rays, Dr. Mohammad typically recommends that patients get a tinted sunscreen product to have truly broad-spectrum coverage.

Q: What is the difference between chemical and physical sunscreens?

A: Explaining to patients the different properties of each filter is helpful — summarizing that while mineral sunscreens reflect or refract ultraviolet radiation, chemical filters absorb it. Dr. Mohammad often recommends physical sunscreens containing zinc oxide and titanium dioxide for lighter-skinned individuals or those concerned with skin sensitivities. For darker-skinned patients, she suggests chemical sunscreens because these products have a more preferable finish on the skin. “Even the micronized sunscreens can still leave a whitish cast that can be cosmetically unacceptable for many people with skin of color, deterring them from using sunscreen again.”

Q: What does SPF mean? Is a high-number SPF better than a low-number one?

A: Patients may have misconceptions about the meaning of the Sun Protection Factor (SPF) number listed on their sunscreen packaging.

Dr. Hamzavi uses the analogy of an umbrella to help patients understand: “If you walk outside for 10 seconds and have a tiny hole in your umbrella, your umbrella will protect you from getting too wet. However, if you go outside for an hour with a hole in your umbrella, you could potentially be soaked. The variable is exposure over time. An SPF 30 just has more holes than an SPF 100.”

Dr. Hamzavi also recommends sharing with patients that SPF is only calculated to UVB rays. Patients may not know that SPF does not take into account UVA or visible light, which can cause photoaging and pigmentation. Because of this, using an iron oxide or a formulation with antioxidants with sunscreen may be advisable.

Q: How can I protect my baby or toddler from the sun? Can sunscreen be applied to babies?

A: One thing to emphasize to patients is that sun exposure during childhood is some of the most important in setting up risks later in life for skin cancer and melanoma, according to Dr. Shinkai. However, reassuring caregivers that the American Academy of Pediatrics and the AAD provide good guidance is also helpful. Caregivers should use sun-protective clothing and shade for babies younger than six months and a combination of photoprotective covering and physical sunscreens after six months. Coverings may include hats, stroller covers, and playshades, among other things.

Staying practical for patients is necessary. “As we all know, there are times in life when you can’t sit under an umbrella. Using sunscreen on exposed areas is really required,” Dr. Shinkai noted. Physical sunscreens are less likely to induce allergic reactions and are deemed safe and effective, Dr. Mohammad highlighted.   

Q: Can I use the sunscreen I bought last summer, or do I need to purchase a new bottle? Does it lose its strength?

A: Dr. Mohammad advises patients to look at both the packaging and the formulation when deciding whether to purchase new sunscreen products. Typically, an expiration date can be found on the packaging. Additionally, she instructs patients to push out some product to examine its consistency. “If the product comes out as oil and then a thick cream, the ingredients are separating, signaling a loss of efficacy.”

If the patient finds the product past the listed expiration date or an unusual consistency, the sunscreen should be replaced.

Q: Will using sunscreen prevent me from getting enough vitamin D?

A: While this may be a concern of patients, Drs. Mohammad and Hamzavi agree that the data does not suggest that this is likely the case. In fact, a 2019 British Journal of Dermatology meta-analysis found little evidence that sunscreen creates vitamin D deficiency in real-life settings, suggesting that concerns about vitamin D should not negate skin cancer prevention advice (https://doi.org/10.1111/bjd.17980).

Dr. Mohammad highlighted that sunscreen does not block 100% of the sun’s rays. Most patients are able to get enough vitamin D from their diet and sun exposure, even with sunscreen. If patients are still concerned about a deficiency, she suggests recommending patients take a supplement.

Q: Are sunscreens safe?

A: To address concerns about sunscreen safety with patients, Dr. Hamzavi emphasizes that simple formulations with a physical barrier have been proven safe and effective. Dr. Mohammad accentuates that sunscreen filters on the FDA’s Generally Safe and Effective (GRASE) list have gone through stringent testing. However, both are transparent to patients that the FDA still has insufficient data for many of the chemical sunscreens on store shelves in the United States.

Dr. Shinkai explains to patients that the science community has known about UV filters in the body for over a decade — which is likely not just coming from the sunscreens people are putting on their bodies. Studies as recent as 2019 and 2020 have indicated some sunscreen systemic absorption. While we know that some data has shown a correlation between sunscreen and alterations on the body, we do not have proven harmful effects of that absorption, Dr. Mohammad emphasized.

In addition to systemic absorption, many patients have concerns about sunscreen and hair loss. Again, Dr. Mohammad clarifies for patients that while some studies have shown a correlation between sunscreen and lichen planopilaris, additional, well-designed studies are needed to determine the accuracy of the results. “I don’t think at this point I would say stop using your sunscreen because it will give you hair loss,” she commented.

While much still needs to be researched about sunscreen in terms of systemic absorption or hair loss, Drs. Hamzavi, Mohammad, and Shinkai all agree on one point: The patient should focus on what data make clear. “We know that sunscreen protects against skin cancer and is very helpful for people who have skin conditions worsened by the sun. We do need further testing of some of these sunscreen filters to have a better idea of the effects or better control in clinical trials. However, the FDA does not recommend that people stop using these sunscreens,” Dr. Mohammad assured.

Q: What can I use if I’m worried about the environmental impact of sunscreens?

A: Dr. Shinkai pointed out that while many patients who worry about the environmental impact of sunscreen may reach for those labeled “reef safe,” this designation does not currently have a regulated or standardized definition and may vary in composition and character.

A large study done by the National Academies of Sciences, Engineering, and Medicine in 2022 pulled together an extensive amount of environmental research and human health information to get a broader understanding of the issue, ultimately recommending that the EPA pursue an ecological assessment to help define what risk the UV filters pose to the environment. This will be a complex study, Dr. Shinkai emphasized, because the way UV filters get into the environment, persist in the environment, and affect different species varies widely.

However, from a human health perspective and as a dermatologist, Dr. Shinkai continues to educate her patients that what we are sure about is that UV protection is important, and that sunscreen is a key player in photoprotection.

Dr. Mohammad instructs patients who are concerned about the environmental impact to use a physical UV blocker and wear photoprotective clothing to reduce the amount of sunscreen they use.

Q: What products can I avoid or use if I think I’m allergic to sunscreen?

A: If a patient is concerned about an allergic reaction to sunscreen, Dr. Mohammad suggests recommending a mineral sunscreen or a chemical product that uses hypoallergenic ingredients. In addition to these topical sunscreens, Dr. Hamzavi also noted that oral adjuncts may be helpful such as some oral antioxidants containing polypodium leucotomas.

Dr. Shinkai reminds patients who are worried about allergic reactions, “Allergy testing, specifically patch testing, to sunscreens may help to identify which UV filters are safe for patients with concerns about allergic reactions.”

Ultimately, helping patients understand what sunscreen is, why it helps them, and which is most appropriate for their skin type and lifestyle comes down to empowering patients to get informed. While the aforementioned suggested talking points can be helpful during patient encounters, dermatologists can direct patients to the AAD Sun Protection Resource Center for more in-depth information.

Additional DermWorld Resources