Answers to Your Summer Parenting Questions: The Research Behind Sunscreen

Is sunscreen safe? What type of sunscreen should you use? Do you really need to reapply every two hours? Does SPF matter?

This long newsletter provides a deep dive into the research on sunscreen. This newsletter will be more technical than most of my newsletters so if you aren’t interested in the research and only want the takeaway message, skip ahead to the “Overall Translation” section at the end. If you are interested in the research, remember that all underlined words link to the research or the source.

Should I Even Be Using Sunscreen on My Kids (and Myself)?

Some research estimates that regular use of sunscreen during childhood may reduce the lifetime risk skin cancer by as much as 78%. However, research is mixed as to whether sunscreen use in the real world actually prevents skin cancer due to other factors involved such as sunscreen use potentially increasing the time spent in the sun. In addition, most sunscreens only provide protection from UVB rays and very little protection from UVA rays, which penetrate the skin more deeply and are also linked to skin cancer.

Yet despite these mixed findings, dermatologists clearly still recommend the regular use of sunscreen, particularly for young children. The American Academy of Pediatrics also recommends sunscreen and emphasizes that “any sunscreen is better than not using sunscreen at all”. Research also finds that children who do not always wear sunscreen are over two times more likely to get a sunburn.

TRANSLATION: Most experts recommend that children regularly wear sunscreen due to potential risk for skin cancer and sunburn.

Source: Kindel Media/Pexels

Is sunscreen safe?

To answer this question, it is first important to explain that there are two types of sunscreen: chemical sunscreens and physical sunscreens. Chemical sunscreens sink into your skin and act like a sponge absorbing UV rays. Physical sunscreens (also called “mineral sunscreens”) stay on the surface of your skin acting like a shield that reflects UV rays. Chemical sunscreens include active ingredients such as oxybenzone, avobenzone, octocrylene, ecamsule, octisalate, homosalate, and octinoxate. Physical sunscreens typically include silicone dioxide, zinc oxide, or titanium dioxide as active ingredients.

A recent study involving only adults found that four common ingredients in chemical sunscreens (oxybenzone, avobenzone, octocrylene, and ecamsule) are absorbed into the blood and that, when sunscreen was applied frequently (four times per day) over the course of four days, the blood levels exceeded what is considered to be safe according to the US Food and Drug Administration (FDA). These findings were confirmed by a follow-up study. This follow-up study also found that these chemicals are absorbed into the bloodstream even after a single use and were still found on the skin and in the blood weeks after using the sunscreen. This study also found that three additional active sunscreen ingredients (homosalate, octisalate, and octinoxate) may be absorbed into the bloodstream. Research also finds that these chemicals may be found in breastmilk and urine after using sunscreen. On the other hand, mineral sunscreens do not seem to be absorbed into the body in the same way.

The long-term health impacts of these chemicals being absorbed into the body are still relatively unknown. In animals, research suggests that these ingredients disrupt hormonal and reproductive systems. Some studies in humans suggest that these ingredients may be linked to reduced fertility in men and changes in birthweight when pregnant women are exposed. Yet, further research is definitely needed to better understand these impacts.

Oxybenzone and other active ingredients in chemical sunscreens also have harmful impacts on the environment such as damaging coral reefs.

TRANSLATION: There is some research suggesting that ingredients in chemical sunscreen may harmful for your health and the environment. Yet, even in light of this data, dermatologists, the FDA, and even the authors of some of these studies still recommend the use of sunscreen. However, if these studies are concerning to you, then you can try mineral sunscreen (which has not been found to penetrate the skin) and/or other measures such as protective clothing. It can also help to give your child a bath after a day of wearing sunscreen to minimize how much of these chemicals are absorbed.

Other strategies for reducing UV exposure that are recommended by experts include wearing hats, sunglasses, and protective clothing and staying in the shade particularly during peak sun hours (10am until 4pm). Research even suggests that wearing long sleeves and seeking shade may be more effective at preventing sunburn than wearing sunscreen.

What about spray sunscreen?

Many experts do not recommend the use of spray sunscreen due to concerns about its effectiveness and potential health implications.

First, research suggests that when spray sunscreen is applied outside, 32-79% of the sunscreen may be lost to the wind. Spray sunscreen often has other chemicals called “propellants”, such as propane, butane, isobutane, or hydrocarbon, which help to spray the product out. However, research suggests that commercially available aerosol spray sunscreen bottles may be 41 to 59% propellant, meaning you may not be getting as much SPF as you think.

However, a recent study suggests that sunscreen sprays with mineral sunscreen may be safe.

TRANSLATION: You may want to avoid chemical sunscreen sprays due to potential safety risks and lack of effectiveness.

What about for babies under 6 months?

Sunscreen has not been studied in babies under 6 months and most experts advise that infants under 6 months avoid sunscreen due to the lack of research and the more sensitive skin in this population. In 2018, the American Academy of Pediatrics changed their recommendation for sunscreen in babies under 6 months, stating that, if necessary, some sunscreen may be applied to small areas of the body to provide protection. However, they also continue to emphasize the importance of avoiding the sun if possible (through protective clothing and avoiding peak sun hours). Experts also recommend washing off sunscreen as soon as the infant is out of the sun and using a mineral sunscreen if possible.

Do I really need to reapply every two hours?

Finally some good news! You actually may not need to reapply as often as you think since research finds that SPF protection may only reduce by 25% 8 hours after application. Another study found that a single application of SPF 25 to children may be adequate for 6 hours of sun exposure but not 8 hours. However, you may want to re-apply more often if there is any swimming, sweating, or friction from clothing or sand involved.

Does SPF matter?

SPF, or sun protection factor, should indicate how much protection a sunscreen provides from the sun’s UV rays. SPF 30 should block out nearly 97% of UV rays, SPF 50 should block out 98%, and SPF 100 should block out 99% of UV rays. This means that the difference between SPF 50 and SPF 100 is likely negligible

However, research finds that the SPF indicated on the bottle of sunscreen usually isn’t accurate and that most sunscreens provide much less protection from UV rays than the SPF would have you believe. In fact, most sunscreens provide about half as much protection from UVB rays as indicated by the SPF rating.

Research also finds that higher SPF values may encourage people to spend more time in the sun, leading them to falsely believe that they are safe from any harmful impacts.

TRANSLATION: SPF values may be an unreliable measure of sun protection. There is likely no reason to use an SPF greater than 50.

OVERALL TRANSLATION

Sunscreen may be important in preventing skin cancer and sunburns but there is some emerging research suggesting that parents may want to avoid some chemical sunscreens and spray sunscreens if possible. Babies under 6 months can use small amounts of sunscreen if necessary and SPF and reapplying sunscreen may not matter as much as you think!

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Welcome to the Parenting Translator newsletter! I am Dr. Cara Goodwin, a licensed psychologist with a PhD in child psychology and mother to three children (currently an almost-2-year-old, 4-year-old, and 6-year-old). I specialize in taking all of the research that is out there related to parenting and child development and turning it into information that is accurate, relevant, and useful for parents! I recently turned these efforts into a non-profit organization since I believe that all parents deserve access to unbiased and free information. This means that I am only here to help YOU as a parent so please send along any feedback, topic suggestions, or questions that you have! You can also find me on Instagram @parentingtranslator, on TikTok @parentingtranslator, and my website (www.parentingtranslator.com).