A MOM’S GUIDE TO UNDERSTANDING SUNSCREEN LABELS

 

80% of a person’s lifetime exposure to harmful UV light from the sun occurs before the age of 18. That’s a staggering figure and, once again, proves that kids do not listen to their elders.

Sunscreen has been shown scientifically to protect us against all kinds of skin damage and several types of skin cancer.

Surprisingly, experts insist that sunscreen should, in fact, be the last line of defense against the sun. Proper clothing and shade are way more effective than sunscreen. The American Academy of Pediatrics recommends that infants under 6 months of age not be exposed to direct sunlight at all and older babies up to toddlers be in the sun very sparingly with lots of sunscreen on (at least 2mg/cm2 of skin).

With that said, there are a few things every parent should know about when reading common sunscreen labels.

 

 SPF rating

It is a controversial, but widely used way to test the efficacy of a sunscreen even though many scientists are skeptical about it. The test is done on human volunteers and estimates the amount of artificial solar energy required to cause redness on the skin. This setup makes the test pretty subjective with many uncontrolled variables. Still, it’s useful, but only as a general estimate. For instance, SPF of 15 or less provides minimal protection against the sun, 30-50 would be moderate to strong, and over 50 gives maximal protection. So, since the PSF test is not very sensitive, we cannot say that a sunscreen with SPF 35 is 5 points  better than one with SPF 30 and you should use that number only as a rough guide.

 

 

BROAD-SPECTRUM

Next, you will probably see something about “UVA and UVB” or “broad-spectrum” protection. Since no single ingredient is good enough to protect us from the whole range of harmful solar radiation, sunscreens typically have a mixture of 2 or more chemicals to cover all the bases, so to speak. The most harmful components of solar energy which get through the ozone layer are UVA and UVB light. Both types will cause skin damage, but UVB carries more energy and even though there is almost 20 times more UVA than UVB in sunlight, it’s UVB that’s responsible for most sunburns. Therefore, a well-formulated sunscreen needs to absorb or reflect both.

 

 NATURAL

Many parents choose products for their kids that are labelled “natural”, “organic” or “green”. This includes sunscreen. You will often see the words “natural” or “natural mineral” on sunscreen containers. Most often, these terms refer to a formulation based on zinc oxide as the main ingredient (hence the word mineral) with various plant oils and vitamins to complete the recipe. These ingredients may originate from organic sources, but the types of ingredients are the same as in generic sunscreens.

 

 NON-NANO

To understand this label, we need to get a quick background on sunscreens. They fall into 2 broad categories: chemical and physical. Chemical ones are based on substances that absorb UV energy from the sun and dissipate it before it can damage our skin. Common ingredients are: parabens (rarely used nowadays), homosalate, oxybenzone, avobenzone. Although they go on easily and leave no trace, these sunscreens have a bunch of drawbacks: they quickly degrade under the sun, requiring constant re-application. Some of the ingredients cause skin irritation. They also get absorbed into the bloodstream through the skin and for many people it’s a concern even though current research shows no evidence that these chemicals cause cancer or interfere with hormones.

What’s the alternative to chemical sunscreens? Physical ones! They are based on titanium oxide (TiO2) and zinc oxide (ZnO) powder mixed with a bunch of oils. They protect the skin by reflecting and scattering harmful UV light with TiO2 better suited for UVB and ZnO for UVA. The big advantages of these sunscreens are: they don’t need frequent re-application (they don’t degrade), they won’t cause skin irritation, they offer excellent protection from the sun when applied evenly, and they won’t get absorbed into your bloodstream.

However, we are vain creatures and the mere fact that these sunscreens leave a white residue when applied makes them less popular. The industry solved the issue by using TiO2 and ZnO nanoparticles which, due to their minute size, do not leave a white film on the skin and, as a bonus, lead to more even skin coverage. However, with every positive there is a negative. These oxide particles promote the creation of free radicals when they interact with sunlight and our skin. To suppress free radical formation, manufacturers now coat their TiO2 and ZnO particles with things like silica. Some fear that these free radicals can lead to cancer, but current research has found no support for this under real life circumstances. Yet another health concern is that nano-particles are small enough to penetrate the skin and may cause damage to the whole body. That’s the reason many manufacturers use particles that are small, but not too small, in other words “non-nano”. Studies have confirmed that most nano-particles in sunscreen only go as deep as the top layer of dead skin cells which is harmless. Some TiO2 nano-particles can go a bit deeper into the epidermis but none of them can fully cross the skin barrier.

 

 HYPOALLERGENIC

Also, you may find statements like “gentle” or “hypoallergenic” on kids’ sunscreen labels and it goes back to the chemical vs. physical distinction. With  a few exceptions, these formulations will be zinc oxide-based since it has no known allergic reactions in contrast to traditionally used chemical sunscreens containing benzones or parabens.

 

 WATER-RESISTANT

This one is pretty self-explanatory. In the past you would have seen words like “water-proof”, but authorities found that misleading since every sunscreen can be washed off to some extent. Now manufacturers must give you an estimate of how many minutes the sunscreen will stay on when you sweat, swim, or both. So, make sure to re-apply according to the instructions.

 

 

 

References (links to primary literature):

 

https://www.sciencedirect.com/science/article/pii/S0020169306000259

https://onlinelibrary.wiley.com/doi/full/10.1111/phpp.12113

https://journals.lww.com/co-pediatrics/Fulltext/2013/02000/Current_principles_of_sunscreen_use_in_children.19.aspx

https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2125.1999.00056.x

https://www.sciencedirect.com/science/article/pii/S0022202X1530885X

https://link.springer.com/article/10.2165/00128071-200001040-00003

https://www.karger.com/Article/Abstract/87606

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0781.2011.00557.x

https://www.jaad.org/article/S0190-9622(09)00539-8/abstract

https://academic.oup.com/toxsci/article/123/1/264/1644613

https://febs.onlinelibrary.wiley.com/doi/full/10.1016/S0014-5793%2897%2901356-2

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3781714/

https://www.karger.com/Article/Abstract/68291

http://www.scielo.br/pdf/abd/v86n3/en_v86n3a13.pdf

 

 

 

 
 
 

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