If ever there was a difficult, controversial topic in cosmetics, it’s sunscreen. At Amazingy we get dozens of questions per month about the subject. It’s always the cause of much discussion, so I felt it was about time to write an article about everything I’ve learned about this topic.
I decided to neglect the guru-talk and home-kitchen-garden knowledge out there as much as possible. Reason: each source is saying something different, making it very difficult to find out what is true and what is not. That’s why I chose to only go on as much scientifically proven reports as I could get my head around. Needless to say, I wrote this article while having a caffeine + 85% dark chocolate induced buzz most of the time.
Finally I’d like to state: I am not a doctor or an authority in this field. I’m just a guy using his common sense. If I learn that I’ve made mistakes around this topic, I will edit the article, although I’m pretty sure the content is all based on the latest scientific research out there.
Don’t feel like reading a lengthy article? Scroll down for my advice and conclusion.
Ultraviolet radiation reaching the earth can be divided into UVA (320–400 nm) and UVB (290–320 nm). An easy way of saying what the difference is between the two types, is to think of UVA as the aging radiation, and UVB as the burning radiation. Your exposure to UV radiation depends on factors such as your current location on planet earth, time of year/day, and atmospheric conditions (clouds, smog, pollution). For example, if you’re sipping a juicy, shaken not stirred, alcohol free (yeah, right!) cocktail on the beach of Barcelona at noon in the summer, the radiation mix is about 94% UVA, and 6% UVB.
Note: UVC rays do not reach the earth’s surface as they are completely absorbed by the ozone layer.
UVB has been the traditional focus — stop the sunburn and all is well. Therefore, the famous sun protection factor (SPF) is a score used to describe the ‘strength’ of the product to protect against “sun-burn”, i.e. mainly UVB radiation. That’s partly the reason why many sunscreens do not block UVA radiation well enough.
This is a problem, because even though UVA does not cause sunburn, it does cause damage to the skin without you noticing it. UVA causes the skin to age faster (oh no, wrinkles! Get me my BB CC DD cream, quickly darling!) and can increase the chances of developing melanoma and photodermatitis. On top of that, not only can UVA pass through glass, its rays penetrate deeper into the skin than UVB does.
If you’ve ever looked like a boiled lobster after spending a day in the sun, you are well aware of the short-term effects UVB can have on you. Short term sunburns can range from some redness to seriously dangerous situations. Long term however, the skin will show signs of both UVA and UVB damage: degenerative changes including premature aging and skin damage, as well as fibrous tissue and circulatory changes. Both are the direct result from chronic exposure to the sun. And then there’s the big C-word we are all worried about: Cancer. Both UVA and UVB are now implicated as cancer-causing, and UV radiation is considered a carcinogen.
Sunscreens marked ‘broad spectrum’, ‘multi spectrum’ or ‘UVA/UVB protection’ usually contain UVA-blocking ingredients such as stabilized avobenzone, ecamsule, oxybenzone, titanium dioxide, and zinc oxide.
We have learned that the SPF level of a sunscreen specifies its level of protection against UVB. To be exact: SPF of 15 filters out about 93 percent of incoming UVB rays, SPF-30 already blocks 97% of UVB and SPF-50 only one percent more, 98%.
In fact, it’s so misleading for consumers that the EU has banned any labels over SPF-50, and in the US, the FDA is also finalizing this long overdue limitation. The EU has also banned labeling claims such as ‘total protection’, ‘100% protection’, ‘sunblock’ and ‘all day prevention’ on any marketing info associated with the sunscreen.
My advice: SPF-15 is a good start since it blocks 93% of UVB. On sunny days or days when you are outside for a longer period of time, the step up to SPF 30 is worth it. Anything over SPF50 seems to be nonsense:
As you can see, it seems like it’s a fair statement that higher SPF products are more about marketing, rather than meaningful differences in potential sun protection. You get better protection using a medium spf sunscreen properly than using a very high spf suncreen badly. And therein lies a big problem: hardly anybody uses enough sunscreen or applies again after a certain amount of time.
SPF values are calculated based on a dose of about 30 ML (1 oz) for the entire body — much more than you and I are probably using. The result: insufficient amounts of sunscreen are applied to achieve the labeled UV protection. In real-world observations of use, actual protection is limited far more by the amount applied, and how often it is reapplied, than by the SPF.
An EWG report illustrates the consequences of inadequate use of sunscreens, based on applying one-quarter of the recommended amount:
As you can see this is a totally different score than the SPF test results, where SPF 30 only allowed 4% to go through. No wonder people still burn when using sunscreens!
Concerning SPF tests and their outcome, there is hardly a difference between the FDA test and the EU Colipa test: the Colipa rating in Europe requires that a UVA protection forms one third of the total SPF rating. Hence, if the UVA protection is SPF 5 and the UVB protection is SPF 30, the overall SPF allowed to be displayed on the product is 15. In the USA, according to the new FDA guidelines from 2012, sunscreen labels can only claim that they offer broad spectrum protection if they protect against both UVA and UVB rays.
So when a product in the US delivers broadband protection, the difference between EU and US SPF is negligable: when a US broadband sunscreen has an SPF of 30, it will get about the same rate in the EU (needless to say all SPF products on Amazingy are broadband!).
However: when the skin after sun exposure reacts with redness, itching or pain, tiny bumps that merge into raised patches, scaling, crusting or bleeding, blisters or hives, you might have a case of sun allergy. The type of sunscreen and amount of SPF that is then needed to keep your skin safe may differ from the above stated recommendations. Stay tuned for a follow up article on sun allergy.
UV Filters reduce the amount of ultraviolet light penetrating into the skin by reflecting, dispersing or converting it into heat.
Particles of titanium dioxide (TiO2) or zinc oxide (ZnO) function are known as physical UV filters. These physical (inorganic) barriers block the skin from sunlight with particulate matter, reflecting and scattering UV rays.
Simply said, the particles act as 1000’s of mini-mirrors on the skin. Physical barriers are near-perfect sunscreens: they protect against UVA and UVB, they start working immediately, they’re stable, seen as safe, and don’t break down in the sun (meaning if you don’t swim or sweat a lot they will still work exactly the same after hours of use, so you don’t need to re-apply).
So why don’t we all use them? Since the zinc oxide and titanium dioxide particles are white, they can cause an undesired whitening effect (the famous white cast) on the skin at high concentrations. This is prevented by reducing the size of the pigment particles to about 200 nanometers (millionths of a millimeter) – which makes them more transparent on the skin.
Physical UV filters in conventional products are used mainly in sunscreens with higher sun protection factors above 25 . They are also used a lot in natural/organic marketed products, because these usually do not use chemical filters. Physical filters are even suitable for the sensitive skin of children and people with allergies.
Zinc oxide is generally seen as very safe. It’s been used without problems for a long time in many skin care products and hardly anybody is allergic to it. It’s anti-inflammatory, and can work wonders on acne (which is why for people with acne, switching from conventional makeup to mineral makeup can help minimize breakouts of adult acne). Zinc oxide sits on the skin so it does not get absorbed or block pores, it can be used on delicate skin and it is a main active ingredient in diaper rash cream used on babies, aiding in healing the skin by protecting it from the warm, moist outside. You can even eat little amounts of it without problems: zinc oxide is even added as a nutrient to some cereals and vitamin pills.
In sunscreens, zinc oxide is known for it’s extremely broadband UV protection and stability. Simply said, nothing happens to it, not even hours after applying it and baking in the sun. It’s very stable and it continues to do it’s job even after hours of exposure. See picture below, where white is before exposure and black after long exposure to strong UV rays.
Titanium dioxide is a bit more controversial, even though when used correctly it is also generally seen as a very safe ingredient. You may not realise it, but titanium dioxide can be found everywhere – you probably use it daily, maybe even without knowing it. 4,5 million tonnes of the stuff is produced each year and it is used in a huge number of products ranging from paint to candy, toothpaste to solarcells, and vitamin pills to smog protection for skyscrapers. Added side effect: did you know it filters out a lot of nastiness from cigarettes?
The problem is that titanium dioxide can be phototoxic. The smaller the particle, the more problems it causes. To suppress the photochemical activity (in other words, make the titanium dioxide more stable), sunscreen manufacturers are now coating the particles with other inert, inorganic ingredients, like alumina, aluminum hydroxide (both not to be confused by the controversial aluminum chlorohydrate) and/or hydrated silica, after which an organic substance like staeric acid is added to the mix in order to make the particles more water-repellent, ensuring that the sunscreen will stay on the skin for a longer period of time. Great, right? Almost! New studies show chlorine in swimming pools can degrade the coating, exposing the nano-partcile sized titanium dioxide.
For more detailed info on titanium dioxide please, see note 1 at the bottom of this article.
First of all, it’s not always size that matters: it is not the particle size that’s always dangerous – we all eat thousands of harmless nano-particles every day. In some substances though, nano-particles can be dangerous.
Most zinc oxide and titanium dioxide manufacturers produce three cosmetic grades of zinc oxide; USP1, a micronized (slightly smaller) grade, and a nanoparticle (super small) grade. You could compare it to a soccer ball, tennis ball, and a marble, just 1000’s times smaller. Manufacturers use the USP1 grade as the starting feed material for the other two grades, which are created through additional processing.
A nanoparticle is a particle smaller than 100 nanometers, or 100 billionths of a meter. Defining whether a powder is non-nano or not is very difficult, as it is virtually impossible to ensure that a product is 100 percent nanoparticle free. Furthermore, many particles are not spherical in shape and thus are difficult to measure. The FDA has declined to weigh in on this controversial issue and currently does not make a distinction between ‘nano’ or ‘non nano’.
In the EU, non nano is defined as ‘the primary particle size is greater than 100nm’, and from July 2013 on, if nano technology was used, it has to say so on the packaging. Australia defines non nano as ‘more than 90% of particles are above 100nm’.
Concerning nano-particles from titanium dioxide and zinc oxide, there are really two opinions. While some scientists say they are potentially dangerous, others say this has not been proven at all. The latest research shows that these particles are not dangerous unless inhaled, which is why they pose more danger in sprays than in creams.
Some zinc oxide manufacturers and sunscreen brands are selling their sunscreen with active UV filters like ZinClear IM50. This supposedly non-nano zinc oxide ingredient should be completely transparant. It is indeed very transparant, but non nano? I don’t think so. They use a technique that clumps together multiple nano-particles.
So is it recommended to use a product containing nano-particles? In sprays: no. In creams: every now and then, but definitely not on a daily base.
Chemical (organic) barriers filter and absorb UV radiation. Their chemical structure converts UV radiation to heat. They vary in their chemical properties, as well as their ability to absorb UVA, UVB, or both.
Research has found that many sunscreens contain chemicals that are estrogenic, which means that they disrupt the endocrine system and can play a role in cancer development. For example, octyl-methoxycinnamate, which is estrogenic and has thyroid hormone-disrupting effects, and homosalate, a hormone-disrupting UVB blocker, can both be found in tons of sunscreens.
A form of vitamin A called retinyl palmitate (or retinol) is present in 20 percent of sport sunscreens and has been linked to the acceleration of skin tumors and lesions when exposed to the sun, according to the EWG. In the US, oxybenzone is still being used a lot in sunscreens, even though this is a known hormone disruptor as well, and has been banned from many countries.
(Tip for readers located in the US: only buy organic/natural sunscreen that uses physical filters!)
A Swiss study states: Few human studies have investigated the potential side effects of UV-filters, although human exposure is high, as UV-filters in sunscreens are rapidly absorbed through the skin.
A startling find: One of the UV-filters, BP-3, has been found in 96 percent of urine samples in the US and several UV-filters in 85 percent of Swiss breast milk samples. The logical next step is to evaluate whether exposure to UV-filters contributes to possible adverse effects on the development of foetuses and children, but this study hasn’t been done yet.
The question to what extent lifestyle can influence the presence of chemicals in breast milk was the foundation for the preparation of the above mentioned questionnaire. The questions were focused particularly on the use of cosmetic products; information on the relationship between the exposure of human populations to constituents of cosmetics and the presence of these constituents in the human body was limited and, in the case of UV filters, absent.
A total daily intake of each individual chemical was calculated for each individual infant, from their individual levels in human milk. Calculation included fat content of individual milk samples, total daily milk intake per infant and body weight of the infant. Some infants exhibited values of daily intake of PCB’ss and several organochlor pesticides that were above US EPA reference dose values.
Margret Schlumpf and Walter Lichtensteiger, who lead the research, stated:
“Research on the effects of endocrine disrupters (chemicals interfering with hormone actions) has shown that it is of utmost importance to obtain information on simultaneous exposure of humans to different types of chemicals because endocrine active chemicals can act in concert. Information on exposure is particularly important for the developing organism at its most sensitive early life stages. Human milk was chosen because it provides direct information on exposure of the suckling infant and indirect information on exposure of the mother during pregnancy.”
Does this mean all chemicals in our bodies come through the skin? Nope. More and more chemicals end up in surface water and we are unable to filter them out. With the consumption of food and water, they accumulate in our body tissue.
Last but not least, chemical UV filters cause damage to coral reeves. See note 2 at the bottom of this article.
Zinc oxide still beats all the other active ingredients out there and offers the most broadband protection of all known UV filters. Coated titanium dioxide follows closely and can be seen as a broadband filter as well.
As you can see in the graphs below, zinc oxide offers great coverage between 290-400nm. In other graphs I’ve seen that in some cases it even offers coverage up to 700nm, while titanium dioxide has good coverage between 290-350nm, but insufficient coverage between 350-400 nm, especially in microfine forms. Both also filter quite a bit of UVC.
From the FDA:
There are many natural oils that could provide protection against UV rays, because of the anti-oxidants they contain. By adding these oils to their sunscreens, manufacturers can use less conventional UV filters while keeping a high SPF. Brands like Eco by Sonya (formerly known as Eco Tan), Alga Maris, Soleo Organics, and Eco Cosmetics use this knowledge to their advantage.
Here are some oils and their SPF value:
Dr. Alkaitis states:
Our entire line has it’s own natural sun protection which is inherent in the plants themselves. The Replenishing Serum is recommended for the face and body before, during and after sun exposure. The Nourishing Treatment Oil and Day Cream may be worn on the face for daily sun protection. They have a natural SPF of about 4.
As you can see, red raspberry seed oil has an incredibly high SPF. The reason is that it possesses an exceptionally high proportion of alpha and gamma tocopherols (aka Vitamin E), vitamin A and omega-3 and omega-6 fatty acids. In a recent study, the oil showed absorbance in the UV-B and even UV-C ranges, suggesting that it may be useful as a broad spectrum UV filter.
P.S: Seems like that caffeine buzz might do more than just keeping me awake: Studies have found that caffeine can reduce the risk of some types of cancer, including non-melanoma skin cancer. Caffeine affects several proteins in a cell, including an enzyme called ATR which senses DNA damage and blocks certain cellular processes, in order to allow affected DNA to be repaired. In another study, inactive ATR had a similar effect to caffeine on skin cells after UV damage. The researchers conclude that this may suggest that caffeine’s UV protective effect, documented in previous studies, is due to ATR inhibition. I’ll have another Americano, thanks!
Titanium dioxide crystals are generally seen in one of two forms: rutile and anatase. The rutile form is more popular due to its higher stability and slightly better whitening abilities, while the anatase form is softer and less abrasive, and therefore popular for healthcare products and foods. In UV products, only the rutile form should be used, but this is unfortunately not always the case. Just a couple of months the Australian government issued a warning about products from Nivea, L’Oreal and Proctor & Gamble using unstable nano-particles of titanium dioxide in their sunscreen. Why this is bad? Because these particles are very unstable:
Some skin cancers are linked to UV-induced free radical damage to the skin, which is why wearing sunscreens with strong broad-spectrum UVA/UVB protection is recommended by medical authorities. However, recent studies have shown that the anatase form of titanium dioxide (and in particular nano-scale anatase titanium dioxide) can increase the formation of free radicals when exposed to sunlight and water. A number of scientists have questioned the safety of their use in sunscreens and other skin products. Anatase titanium dioxide is an aggressive free radical producer, compared to rutile titanium Dioxide.
In 2008, a peer reviewed study found that nano anatase titanium dioxide in sunscreen was reacting with sunlight and breaking down the coating on steel roofing in a matter of weeks. The study raised serious concerns about the impact these ingredients may be having on our skin. In 2010, Italian scientists warned that nanosized anatase titanium dioxide is ‘capable of destroying virtually any organic matter.’
Chemical sunscreen causes coral damage: According to a prominent scientific study by Roberto Danovaro and team at the Marche Polytechnic University in Ancona, Italy, Sunscreens can damage coral reefs. Up to 10 percent of the world’s coral reefs may be threatened by sunscreen induced coral bleaching.
Their paper is entitled ‘Sunscreens Cause Coral Bleaching by Promoting Viral Infections’, and it was published in the peer reviewed journal Environmental Health Perspectives in 2008.
Each year between 4000-6000 metric tons (4400-6600 US tons) of sunscreen washes off swimmers and snorkelers into coral reef environments.
Four common sunscreen ingredients were shown to cause complete coral bleaching at very low concentrations. They are:
Other factors such as global warming, pollution, and human activities are likely a far greater threat to coral reefs than sunscreens are at this point. However, that is not a reason to ignore the results of this research. There has been limited criticism of this study, but it is good peer-reviewed science, and the results should be taken seriously. Anyone swimming or snorkeling in the tropical ocean near coral should consider using a coral reef safe sunscreen.
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Amazingy's Jack of all Trades. Skincare specialist by day, computer nerd by night.
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