There is a lot of hype around sunscreen safety, and I think it is important for consumers to be informed from accurate sources regarding the issues at hand. See my original post here about sunscreen safety.
Today I wanted to specifically address the issue of nanoparticles. A lot of natural and organic sunscreens are marketing their sunscreens as “non-nano.” Why? The ingredients most likely to be nanosized are zinc oxide and titanium dioxide, which are top of the list for the “safe” sunscreen movement. So are the “safe” sunscreens not safe either???
Nanoparticles refer to the size of the particles in the sunscreen. They are one billionth of a meter in length, aka a nanometer. Nanotechnology, the ability to create something that small, has revolutionized many industries, cosmetics included. And they’ve actually been used in sunscreens since the early 1980s!
Well let’s first look at the practical aspects of nano sunscreens. It has transformed the 1960’s white noses of lifeguards to inconspicuous, non-obnoxious sun shields. Since the particles are so small, they don’t have the light reflectivity and whiteness of old-school sunscreens. “Invisible zinc” is what some companies use to describe the technology.
But are they safe? If they are so small, can’t they penetrate through the skin and affect biological functions?
Luckily, nanoparticles are coated and only reach the very top level of the skin (the stratum corneum), where they reflect UV light. Additionally, our normal shedding of skin continuously removes them. Finally, in nature, the nanoparticles tend to clump, making them larger than true nanosize, but smaller than traditional zinc oxide particles (see figure). These real-life clumped nanoparticles definitely cannot penetrate the skin because they are too large, again easing fears of absorption. Don’t take my word for it, it’s been tested numerous times, and the sunscreens simply aren’t absorbed.
Nanoparticles clump on the skin. Photo credit:PMID: 22123418
Finally, a last concern was regarding the generation of pro-oxidant reactive oxidative species (ROS), as was found in some cell studies. Luckily, since sunscreen nanoparticles are coated in silica, an inert substance, they actually have no risk of generating ROS in the highly fine-tuned human body. Finally, in case you were worried (everything worries us now!), sunscreen nanoparticles were tested for both cancer-causing properties and phototoxicity and they were completely in the clear (Wang, 2011)!
Let’s also remember the long safety track record of both zinc oxide and titanium dioxide. Titanium dioxide is found in toothpaste, lotion, skimmed milk, cottage cheese, while zinc oxide is what we smear on our babies bottoms (diaper cream) and have used in our dandruff shampoo for decades.
For all the criticism of the FDA [i.e. not doing enough to regulate over the counter ingredients (true), not approving sunscreen ingredients fast enough (true)], at least they are on par with their more modern overseas counterparts. The European Union (EU) considers micro- and nanoparticles safe. The EU usually bans ingredients deemed unsafe/questionable before the US, so if they are OK with nanoparticles, you should be too.
An even stricter critic is the EWG (Environmental Working Group). While we often don’t agree, in this case, we do! The EWG tells consumers not to worry about nanoparticles! The EWG in general tends to favor zinc oxide and titanium dioxide sunscreens over chemical based sunscreens, and most of the commercially acceptable zinc and titanium-based products are nanosized. To date, no environmental repercussions have been discovered, and while continuing monitoring and research is needed, in general nano-sized zinc is A-OK by the EWG.
In conclusion, I don’t worry about the molecular size of my sunscreen ingredients. I’m just happy I don’t have to walk around with a white face to get good daily UV protection!
Why, might you ask, did I attempt to try to make my own sunscreen? Boredom on vacation?
I think many of us are attracted to do-it-yourself home remedies. They seem cheaper and it might make sense to use things that are already in the cupboard. For instance, apple cider vinegar seems to be the internet/Facebook “cure-all” – it can fix everything! Pretty soon I started noticing links for how to make your own sunscreen. I haven’t tried apple cider vinegar yet, but had to try this one.
My homemade sunscreen experiment. Can anyone spot the most essential ingredient in the realization of this blog? Hint – it’s in blue (baby monitor a.k.a nap time).But does it really work? In the case of sunscreen, I wanted to find out for myself.
Those looking for natural or organic solutions are particularly ripe for getting misinformation or potentially dangerous advice. There are MANY excellent natural solutions, but usually those giving advice (i.e. your friend on Facebook) don’t have any medical background, making it hard to vet what is SAFE and effective.
As many of you already know, I’m very passionate about sun protection, and wanted to make sure that people weren’t getting bad information. I was optimistic, hoping to be surprised! With this in mind, I set out to make my own sunscreen.
Zinc oxide powder ready to be added to the base.Here were the pros:
It was relatively easy and fast to make.
There were only a few ingredients, which should please simplistic and naturally oriented people. (Ingredients: coconut oil, shea butter, zinc oxide, pomegranate oil, and lavender oil).
I did not burn while wearing it for 2 hours in the noon Florida summer sun.
Here were the cons:
It cost me $57.70 to get all the materials!
It was messy to apply. Commercially formulated containers exist for a reason. Next time I would transfer it to a squeeze bottle.
Forget re-applying (one of the most common mistakes people make is not reapplying their sunscreen) – it would be way too messy to transport this DIY sunscreen.
I felt like a human version of “Slip-N-Slide” after applying. The texture was way too greasy for my taste.
The true SPF of the concoction is unknown – a major no-no for me.
The stability and expiration date is unknown – I would guess that you could keep this mixture for 60 days, and then have to repeat the process. (I have absolutely no data to support this, which is the point… how do you know if it’s still good?)
The ingredients separated after mixing – not a big deal – just required mixing again before applying. A few days later the mixture was more consistent and paste like.
I would not recommend using this on your face if you are break-out prone. The oils might cause an acne flare.
My conclusions:
Save the $57.70, buy a $15 sunscreen with SPF 30+ and UVA protection, and use the rest of the $$ for a good sun shirt! (Find my sun shirt picks here!)
And a last few words. Some websites advocate using coconut oil alone as sunscreen – this is NOT OK! Coconut oil has an SPF of about 4-6. Would you ever consider buying a sunscreen with SPF 5? No, so don’t consider it adequate protection for your skin. The American Academy of Dermatology recommends a broad-spectrum sunscreen with an SPF of at least 30. We are talking about a serious cancer risk (1 in 5 Americans will develop a skin cancer in their lifetime), as opposed to any hypothetical concerns about ingredients – see my in-depth post about sunscreen safety here. The mixture above includes zinc oxide powder to beef up the SPF. Even easier, you can also very easily find some simple commercial sunscreens with zinc oxide.
While my experiment “worked” in that I didn’t get burned, the practical aspects of the homemade sunscreen made it a no-go for me. It was too expensive, too greasy, too messy, and in my humble dermatologist opinion, a little too risky for me. I’m ok with using a homemade milk mask, but I don’t like risking DNA damage to my skin cells because I messed up the SPF formulation. I’ll leave that to the experts.
It takes just two painful sunburns to increase your risk of melanoma, so for me, it’s really not ok to experiment with sun safety. I did it for you, so that you won’t have to!
In the end, my main message is to use something that you know has an SPF of over 30, reapply every two hours, and practice sun safe behaviors.
Dr. Jacquelyn Dosal is a Board-Certified Dermatologist practicing dermatology in Miami, FL at Skin Associates of South Florida and is a voluntary Assistant Professor at the University of Miami.
I LOVE my gel manicures! Lasting at least two weeks, gel manicures have finally made my pincers look pretty! Like many of you, I had been wondering about the safety about the UV lamps that are used to cure the gel manicures. They seem fairly benign, but there has been some press questioning its safety.
When I read a recent issue of JAMA Dermatology, I was relieved to read that the authors concluded that the risk of skin cancer was very very low with gel/UV manicures, even with regular use. This is what I suspected, so I stopped worrying. Additionally, my salon recently introduced an LED nail lamp, which also seemingly solved the issue of the UV lamp.
Well, imagine my surprise when this topic came up again at the most recent American Academy of Dermatology Annual Meeting. Nail expert Dr. Chris Adigun reopened my concerns about the safety of UV lights. She argued that the lamps are notoriously variable in their UV exposure, nail salons hardly ever follow manufacturer recommendations, and that the UV exposure is more than we previously thought.
This really left me conflicted, since I adore my gel manicures, and I really hadn’t prepared myself to abandon them anytime soon. So I took it upon myself to read through all the relevant articles on the subject (I hate taking someone else’s word for it). Luckily, several groups have studied a variety of nail lamps, with a variety of hand positioning and exposure times.
Here’s the summary:
The amount of UV exposure is WAY below anything close to skin-cancer-causing levels.
Here are a few other important take-away points:
Out of 72,709 women getting regular manicures for 60 years (assuming generous exposure times), only one woman would develop skin cancer who wouldn’t otherwise (in statistics, this is called the “number needed to harm”).
It would take 250 years of weekly gel manicures to equal that of a therapeutic phototherapy session that I commonly prescribe for psoriasis (15–30 treatments over 5–10 weeks). (Yes, phototherapy is often UVB, rather than UVA, but this JID study measured UV dose in J/cm2, and gives a risk comparison to something we already know to be safe).
From a skin cancer perspective, the risk of skin cancer from nail curing lamps is very low. However, it is important to note that ALL lamps used to cure gel manicures emit UVA radiation, even the LED lamps. Despite the lack of “UV” in the name, LED lamps are actually more intense than UV lamps and emit more UVA.
As a quick review: UVB rays cause sunburn and skin cancer, while UVA rays penetrate deeper into the skin, causing skin aging, cell damage, sun spots, and wrinkles by breaking down collagen and elastin (and to a lesser degree than UVB, also contribute to skin cancer).
UVA penetrates deep into the skin to affect collagen and elastin, causing wrinkling, blotchiness, and poor skin tone.UVA radiation is responsible for the brown spots (“liver” spots or “sun” spots) on your grandmother’s hands, as well as the wrinkles and crepiness of the skin.
There’s nothing worse than a youthful face that has been preserved with good skin care, but “old” looking hands.
While the risk of skin cancer is much less than ambient exposure to natural sunlight, the cumulative effects of UVA exposure can result in discoloration and premature aging of the skin.
The typical appearance of a photoaged hand. Note the blotchy appearance of the skin, brown spots, and thinned skin overlying the veins and tendons of the hand. This occurs with regular exposure to UV light, especially UVA, which is emitted in all nail curing lamps and penetrates windows.So your gel manicure won’t significantly increase your risk for skin cancer, but why risk any UV exposure?
For the very sake of preserving the youthful appearance of your hands, I recommend at least the application of a broad-spectrum sunscreen with an SPF of 30+ (see here for recommendations), or sun gloves while having your hands in the lamp. My feeling is the gloves are better.
I use these sun gloves made by BloxSun– I wear them driving and bring them to the salon.
YouVee sunshields are currently crowdfunding – they are very cheap disposable hand protectors that block 99% of all UV radiation. Wouldn’t it be great if salons started carrying these?
In summary, I’m going to keep getting my gel manicures (thank goodness)!
For many of us women on-the-go, the gel manicure is here to stay! Just be sure to protect those hands! And as with anything, it’s good to take a break once in a while from manicures to give your nails a breather.
Shipp et al. Further investigation into the risk of skin cancer associated with the use of UV nail lamps. JAMA Dermatology 2014;150(7):775-6.
Diffey BL. The risk of squamous cell carcinoma in women from exposure to UVA lamps used in cosmetic nail treatment. British Journal of Dermatology 2012;167:1175-1178.
Markova A, Weinstock MA. Risk of skin cancer associated with the use of UV nail lamp. Journal of Investigational Dermatology 2013;133:1097-1099.
Macfarlane DF, Alonso CA. Occurrence of non melanoma skin cancers on the hands after UV nail light exposure. JAMA Dermatology 2009;145(4):4479.
Curtis J, Tanner P, Judd C, Childs B, Hull C, Leachman S. Acrylic nail curing UV lamps: High-intensity exposure warrants further research of skin cancer risk. J Am Acad Dermatol 2013;69(6):1069-70.
Dowdy JC, Sayre RM. Nail curing UV lamps: Trivial exposure not cause for public alarm. J Am Acad Dermatol 2015;6(64):e185-6.
Sticking to those New Years resolutions? Need a little motivation? Maybe I can help. Many of the good things we do for our body and mind can have a positive effect on our skin. What a nice bonus! Don’t we all want glowing skin?
Let’s review below:
Move daily – Get that blood flowing and move daily! Whether it’s a walk, a fitness class, yoga, or pilates, just move your body.Research shows that individuals over 65 who performed at least 3 hours of moderate to vigorous exercise a week were able to reverse the signs of aging. Compared to non-exercising seniors, skin biopsies from the buttocks of the exercising individuals showed features that looked more like a 30-year-old! Exercise gets the blood flowing, brings nutrients to your cells, lowers stress, strengthens the immune system, and much more.
My husband and I recently got the FitBit fitness tracker, and it has been agreat motivation to go for a walk rather than sit in front of the TV. We challenge each other to who can walk the most steps in a day. Depending on the day, the recommended 10,000 steps can be very easy or almost impossible to accomplish without some effort. We have to consciously prioritize a walk or activity over TV or work. Considering the modern lifestyle that leaves us sitting in front of the TV or computer for hours, the challenge to be more active is a welcome initiative. The line “Sitting is the new smoking” has resonated with many folks, myself included. Now that you know it’s also good for your skin, get moving!
Avoid added sugar – I think most of us can agree that there is an over-abundance of sugar in the American diet. Sugar is added to just about everything we encounter in the grocery store (which is why the advice of shopping the perimeter of the grocery store is so true). And why wouldn’t manufacturers add sugar? It makes everything taste better! Sugar actually coats innumerous targets in the body, making them function subpar. Most important to the skin, sugar also coats collagen (a process called glycation) and makes it stiffer, making our skin look sallow, aged, and stiff. So think twice before that second helping of dessert… it may taste sweet but may be making your skin look sour!
Get more sleep. This should be on everyone’s resolution list! Sleep is the time when the body can repair itself. Sleep deprivation means more stress and increased cortisol levels. Increased cortisol levels can wreak havoc on the skin and cause acne breakouts, skin rashes, andworsening eczema or psoriasis. Make sleep a priority. Turn off the TV earlier than usual, make yourself a cup of tea, settle down with a good book (preferably paper and not on a screen like an ipad, as the light prevents the brain from knowing sleep is near), and try to start this routine 30-60 minutes earlier than usual. You will be surprised how refreshing it can be.
This last resolution that may not have been on your list… but it’s an easy resolution to keep — and you can start it at any time, it doesn’t need to be New Years! WEAR SUNSCREEN EVERY DAY, 365 DAYS A YEAR! Put one of my favorite sunscreens next to your toothbrush, and put it on every morning, rain or shine. Do I need to show you the twins? One wore sunscreen and the other didn’t.
While the photo may look exaggerated, all of us will eventually experience some of the tarnishing effects of the sun such as brown spots, dry skin, and/or wrinkles. I got my first brown spots after only 5 years of living in the Miami sun!
Damaging UV rays penetrate car and building windows, so it doesn’t matter if you “never go to the beach.”
Unless you live in a windowless basement and never leave the house, you are always encountering damaging UV rays. Love your skin and apply a sunscreen daily… you will thank me later!
And…. you have my permission to cheat once in a while…. but only with a glass of red wine and a piece of dark chocolate… both are great for the skin! Resveratrol and antioxidants, baby!
Summer is the time where I get alot of questions regarding sunscreens. It’s no wonder… the flood of information out there can be very confusing. I offer up a fairly comprehensive summary of what you need to know this summer to protect your skin. Here are some basics:
Considering that SPF was determined using experiments with 2 mg/cm2 of sunscreen, which is way more than anyone uses in real life (we generally use less than 1/3 of what we are supposed to), we are all getting less protection than we think. For that reason, I usually recommend an SPF of 30 or more (the sun laughs at less than SPF 30, especially here in Miami), one with the label “Broad Spectrum,” and to reapply every two hours. UVB rays cause sunburn and skin cancer, while UVA rays penetrate deeper into the skin, causing skin aging, cell damage, sun spots, and wrinkles by breaking down collagen and elastin. It is important to block both of them, and SPF only indicates the UVB protective power. “Broad Spectrum” indicates that the particular brand also blocks UVA. See this lovely infographic by Dr. Michelle Levy that illustrates how UVA and UVB damage the skin.
Why not use SPF 100?There is a miniscule incremental benefit in protection above SPF 50, so much that the FDA proposed banning the labeling of higher SPFs, as it can be misleading to the public. SPF 100 blocks 99% of harmful UVB rays, while properly applied SPF 50 blocks 98% of the same rays. Something about an SPF of 100 gives people a false sense of security, and they are more likely to improperly use it or expose themselves to the sun for longer. Additionally, there is some evidence that having the very high SPF makes it more difficult to chemically formulate a sunscreen with great UVA protection, which is just as (if not more) important as UVB.
Reapply! The most common reason for sunburn is missing an area of your body and forgetting to reapply every two hours.
There are so many sunscreens on the market, how do I know which one to use?
I classify my sunscreens by the type of use: everyday use, intense sun exposure (like going to the pool or beach), athletic use, and those for babies. Let’s start with babies:
Babies: Baby’s skin at less than 6 months of age hasn’t yet developed the same type of barrier protection as an adult. For that reason, the American Academy of Dermatology will generally recommend sun avoidance or sun protective clothing (look for clothes labeled with UPF- iPlay makes great ones). When sunscreen is needed, a physical sunscreen is best. Physical sunscreens bounce UV rays off the skin, as opposed to chemical sunscreens which are excellent at protecting the skin, but baby is more likely to be sensitive to these products (note: most sunscreens are chemical sunscreens). You can recognize a physical sunscreen because it only has one or two active ingredients: zinc oxide or titanium dioxide. These are some of my favorites: CeraVe Baby, Neutrogena Pure and Free Baby Sunscreen, Blue Lizzard Baby. (I don’t like the one made by the Honest company — I find it very hard to rub in and sticky).
Beach or pool use: As mentioned earlier, a Broad-Spectrum sunscreen with an SPF of at least 30 is best. Water-resistant (now labeled as 40 or 80 minutes) is also a must. The key is to reapply every 2 hours! Pick your favorite and go with it… Sunscreen only works if you use it! Here are some of my favorites: La Roche Posay Sunscreen Milk, Neutrogena Ultra Sheer, Coppertone Oil-Free Faces, Neutrogena Beach Defense.
Everyday Use: Yes, you should be wearing sunscreen every day!!! It’s not only to protect yourself from skin cancer, but if you want to look young, the MOST important intervention is sunscreen! See the difference between these twins, one who practiced sun protective measures, and the other who didn’t. The twin that protected herself from the sun looks at least ten years younger than her twin sister. Having a tan can be nice in the short term, but your skin will pay for it. By the time most people hit age 30, their skin can start to show their prior indiscretions! Time to embrace your inner Anne Hathaway. Pale is beautiful.
The sunscreens I like for everyday use are those that feel like a moisturizer, are very light and sheen, and layer well under makeup. Sunscreen should be layered under your makeup, even if your makeup contains SPF…. it’s not enough. Here are my favorites: Elta MD UV Clear, La Roche Posay AOX Serum, Neutrogena Healthy Defense, CeraVe AM.
Athletic Use: This is a tough one. Intense exercise or very hot conditions cause you to sweat like it’s raining. Even water resistant sunscreens can be tough to keep on, and forget reapplying on that wet skin. I’m still in search for a good one, and would love to hear your comments/recommendations below! I would definitely recommend UPF moisture-wicking clothing for tennis, fishing, or other activities, as these actually keep you more cool than tank tops and have consistent sustainable sun protection.
Sprays: Personally, I love the convenience of sprays. However, it seems like people are more likely to under-apply or miss certain areas of their body, potentially leading to sunburn. There are also some questions about the possibility of inhaling the aerosolized chemicals, and we don’t yet know the dangers of this. I still use sprays sparingly when I need the convenience, but the jury is still out as to their proper role.
When should I be using a non-chemical (a.k.a. physical) sunscreen?
The majority of sunscreens on the market contain excellent scientifically developed chemicals that block a combination of UVB and UVA rays. For the vast majority of people, chemical sunscreens are perfect. In some cases, a physical blocker is preferred. For instance, in babies less than six months of age, I recommend a physical blocker for reasons stated above. There are 3 other scenarios where I prefer physical sunscreens: sensitive skin, rosacea, and melasma.
I know many people who tell me they are allergic to every sunscreen that they have tried. My bet is that they have not yet tried a purely physical sunscreen, as they can be difficult to find. While regular sunscreens have a fairly high rate of allergic contact dermatitis, physical blockers have almost no reactive potential. These are my favorites for non-facial use: Neutrogena Sensitive Skin, Neutrogena Pure and Free Baby Sunscreen, Blue Lizzard. See below for facial sunscreen recommendations.
Do you suffer from flushing, red pimple bumps, skin burning, and/or sensitivity to most products? Well then you might have rosacea, and I definitely prefer for you to wear a physical sunscreen. Rosacea and melasma (those brown patches on the face that come with sun or pregnancy) are very sensitive to heat, and chemical sunscreens produce an imperceptible amount of heat, potentially flaring the skin. In order to minimize anything that can exacerbate rosacea or melasma, I recommend a pure physical sunscreen for these heat sensitive conditions. Physical sunscreens bounce the UV rays off the skin, and are inactive on the skin. In both rosacea and melasma, sunscreen is mandatory. You will find with changing sunscreen alone, your skin may dramatically improve. These are my favorite physical sunscreens for daily facial use: La Roche Posay Anthelios Mineral SPF 50, Elta MD UV Physical SPF 41, SkinCeuticals UV Physical Defense, CeraVe SPF 50 Facial Sunscreen Lotion, Avene Mineral SPF 50. And don’t forget to reapply. For the sake of convenience, I like the following two products to help women reapply sun protection after they have applied their makeup. No one wants to put on a lotion sunscreen to a freshly painted (ahem, made-up) face. Use these products to layer on top of your pretty face throughout the day: Avene compact, Colorescience Sunforgettable Mineral Powder Brush.
In conclusion, don’t forget to practice other sun safe behaviors, such as wearing polarized sunglasses, protective clothing such as hats, UPF clothing, UPF scarves (see these great ones by Blox Sun), and seeking shade during peak hours of UV intensity, 10 am to — 4 pm.
I’d love to hear your thoughts and invite you to comment below!
Stay tuned for my take on the topic of Vitamin D and the Environmental Working Group’s rankings of sunscreens.
Photo credit: Shutterstock
Dr. Jacquelyn Dosal is a board-certified dermatologist practicing in Miami, FL. About Dr. Dosal: http://goo.gl/hbgqZW
Is my sunscreen going to kill me? Perform a search on sunscreen safety and some scary stuff shows up! Retinyl palmitate causes skin cancer. Oxybenzone causes estrogen-like effects on the body. I have seen these statements repeated over and over again all over social media and in real life. I recently heard from a patient, “I was using Neutrogena but then stopped because I heard it wasn’t so good for you.” How do we protect ourselves and our families from skin cancer without any nasty side effects?
I’d like to offer up my take — from a organic-loving, Whole-Foods-shopping, yoga-practicing, green-tea-drinking MD (dermatologist), with an eye for interpreting both media and science…
For those not able to read the whole post (we are all busy, I know!), here’s the quick summary of my findings. You can read on for more info too!
Sunscreen won’t cause hormonal disruption — it would take 200 years of application to even reach questionable levels of exposure.
Sunscreen won’t cause skin cancer — the use of sunscreen is directly correlated to the prevention of skin cancer. Retinyl palmitate is an anti-oxidant that occurs naturally in the skin.
Nanosize sunscreens are safe for use, as they clump in real life, preventing them from being absorbed.
I’ve researched the issues of sunscreen safety personally, and WOW! It’s confusing and contradictory. I’ll at least say this— we always need to critically and scientifically analyze the sunscreen ingredients we use for both efficacy and safety. And just as important, let’s not perpetuate myths that are based on unsound science. If you are interested in sorting through the muddy waters of sunscreen information — read on!
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Environmental Working Group’s Rankings of Sunscreens.
Most of the information about safety stems from the Environmental Working Group’s sunscreen rankings. The Environmental Working Group is a not-for-profit organization that searches to identify harmful chemicals in our environment. While I applaud the intentions of the EWG to find safe and environmentally responsible materials, we need to be fair and look at these issues seriously, and not just solely how presented by the EWG.
Do sunscreens cause hormonal disruption?
The EWG advises avoiding any products with oxybenzone (an excellent UVA and UVB blocker) as it may cause effects similar to estrogen. The concern comes from a study performed in rats, where the rats were fed supratherapeutic doses of sunscreen (let me say that again, the rats ATE sunscreen at megadoses), and the size of their uterus enlarged.
Edited graph from PMID 11333184
There is a monstrous difference between eating super high doses of sunscreen and applying it to your skin daily — and concluding that topical use in human sunscreen causes estrogenic effects is an unrealistic stretch. A study in 2011 in JAMA Dermatology showed that it would take 200 years of daily sunscreen application to reach the same amount of exposure as the rats in this study. To the author’s credit, their word-for-word conclusion in the abstract was: “Our findings indicate that UV screens should be tested for endocrine activity…” The authors do not say that the UV screens cause hormone activity in humans… they can’t. In order to substantiate their EWG’s claim, you would need to show hormone disruption in real live humans.
Luckily, such a study was performed. Human patients applied more than 3 times the real-life quantity of a high percentage oxybenzone sunscreen (10% oxybenzone, compared to the commercially available 6% oxybenzone) to their whole body daily for one week. Oxybenzone was in fact detected in the urine of the volunteers (as have some other sunscreen agents). Sound the alarm bells! — this is concerning. It indicates that there is some absorption from topical use (medications that are applied directly to the surface of the skin). However, the body quickly excreted it through the urine (which is a good thing). Much can be said about the fact that it was absorbed, but the take-home message was that the researchers were UNABLE to show a hormone disruption despite this absorption (again, this was at 3 times real-life dosage). There was no accumulation of the ingredients over time.
So we have a study in humans of real-life sunscreen use that shows no hormonal effect, or a study where rats ate sunscreen — which do you believe?
To be fair, when researching this blog post, I did come across an alarming number of lab and animal studies showing absorption of various sunscreen agents, with some experiments suggesting hormonal disruption. There were almost as many studies that showed no absorption nor hormone disruption. A good summary of those studies can be found here. But we have to look at what’s important… no human studies have shown hormonal disruption, and that is what counts.
Of note, it is important to mention that oxybenzone can cause allergic skin reaction in a fair percentage of people, so there should be some caution with its use.
And by the way, soy is weakly estrogenic. Where are the cries for banning or avoiding soy milk because of hormonal activity? There are many natural skin care products on the market containing soy, several of which I recommend and are excellent. A little perspective is important, and we need to remember that topical use is very different from ingestion.
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Let’s move on to sunscreen and skin cancer.
Does my sunscreen increase my risk of skin cancer?
A few years ago there was media buzz about a toxicology study that suggested that retinal palmitate, a common inactive ingredient in sunscreens, may actually increase your risk for skin cancer by increasing oxidative damage, or reactive oxidative species (ROS). Oxidative damage is like rust on metal — it corrodes our body and makes us more prone to inflammation and cancer. Let’s dive into this deeper.
Retinyl palmitate is an interchangeable form of retinol that is present naturally in our skin, and this should already be a clue that it’s not dangerous. Retinyl palmitate is not just in sunscreens; is approved by the FDA for use in prescription and over the counter medications, as well as a food additive in dairy products and cereals. It was selected for testing due to its prevalent use in common agents, not for any concerns of safety up to that point.
Once again, we have to look at the details of the study that created the buzz. It was never published in a peer-reviewed journal (the standard for medical literature — data needs to be vetted by people in-the-know), and was not performed in humans (also a huge red flag). It was performed in hairless mice, known to have an already increased risk of skin cancer, and these mice were burned with and without retinyl palmitate (RP). The studies showed the production of oxidative damage and increased risk of malignancy. However, these studies take RP out of human context, which is a very complex interactive antioxidant system. According to Dr. Steven Wang, the lead investigator in the study, “when a sunscreen with retinyl palmitate is applied to the skin, a number of antioxidants work together to alleviate the risk of free radical formation seen in these in vitro experiments. If studied on its own — outside of this environment — its antioxidant properties can rapidly be exhausted, allowing the production of oxygen radicals. In these non-human studies, retinyl palmitate was the only compound studied — making the biological relevance of these findings to humans unclear.” Even the lead investigator is not ready to recommend avoiding retinyl palmitate.
The final and probably most convincing evidence of the safety of retinyl palmitate comes from real life use in humans. We often use the family of retinoids (of which retinyl palmitate is a member), as a pill for the prevention of skin cancers in those most at risk (immunosuppressed organ transplant patients). We also have decades of experience using retinoids in acne medications; and topical retinoids are one of the best anti-aging creams on the market — I personally use one (Retin-A) every night. Undeniable humanresearch shows it can reverse oxidative damage and signs of aging, keeping the skin healthy and youthful.
If you are interested in more, I encourage you to read this summary by the Journal of the American Academy of Dermatology detailing the properties of retinyl palmitate and discussing its safety.
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What are nano particles, and are they safe?
Nanoparticles are molecules that have been divided into nanometers (one billionth of a meter). By making the molecules small, it makes sunscreens more cosmetically acceptable and elegant, thus making it more attractive for people to use (i.e. not thick, sticky, or opaque like the old sunscreens found on lifeguards’ noses).
Concerns arose that these molecules might be small enough to penetrate through the skin into the bloodstream. Time and time again, human studies have shown that these particles are unable to penetrate through the skin because, in nature, these nanoparticles aggregate into clumps that are too large to penetrate the skin. There was also some thought that these ingredients could increase reactive oxidative species (ROS). We now know that this is meaningless if tested outside of the complex human antioxidative system. With this in mind, we should all embrace these new technologies that makes sunscreens less opaque, pastey, and more consumer friendly!
Nanoparticles clump on the skin. Photo credit: PMID 22123418
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Be Cautious of Media Sound Bites
The EWG extrapolates data (usually from animal studies, not humans), and uses scare tactics to make us feel like we are hurting our children if we use certain products. What I don’t like is that they ignore actual sound studies that show safety in humans. Their sound bites are alarming and catchy for headlines. I’ve actually seen website titles citing the EWG reading: “The Most Dangerous Sunscreens For Kids (And They’re Probably Hiding in Your Beach Bag).” Talk about mommy guilt!
I love this story which explains why we need to critically interpret how the media presents headlines: Chocolate Causes Weight Loss!
Background: A scientist wanted to show just how easy it was to convince the media to pick up a poorly designed faux scientific experiment that was catchy for headlines. It was a completely fake, but intriguing idea — eating chocolate can help loose weight. It turns out, it was really easy to get experienced journalists to pick up the headline! Read here: I Fooled Millions into Thinking Chocolate Helps Weight Loss. A critical eye is really needed in these days of rapid information sharing.
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What does this all mean?
I don’t agree with the EWG rankings. Many of the poorly ranking sunscreens are very reputable and excellent brands. You can’t take the data from one animal or lab study and ignore other science and human experiments that are in disagreement. That’s not how science works. That’s the reason why thousands of drugs that work in animals never get to the market — because animal studies and in vitro studies often don’t translate into efficacy in the complex environment of the human body.
While in general, I’m in favor of the organic movement, real foods, and responsible farming practices, I often laugh when I see websites recommending chemical-free everything, including sunscreens. Chemicalsarein everything, and there is no such thing as a purely chemical-free susncreen. Of course, live in moderation — extreme use of any susbtance can lead to some bad effects, but to say that normal day-to-day use of products causes the same effect seen with extreme use or oral ingestion doesn’t make any sense.
As this EXCELLENT video describes, the dose is the poison, not the chemical itself. Almost any substance, including natural or beneficial substances, can be toxic under certain conditions, such as high temperatures, pH, concentrations, or when in the presence of other chemicals. Even too much Vitamin C can be lethal to skin cells at certain doses. The age-old mantra still holds true — everything in moderation.
Let’s thank the EWG for their laudable efforts in keeping us safe, but ask them not to demonize valuable products when the science shows otherwise. I completely agree that more testing needs to be done on household and cosmetic ingredients, but I wish they were a little more unbiased when it came to promotion of their agenda. And the media perpetuates these news snippets with negligible investigation into the validity of the EWG claims. It serves our society poorly.
Feel good about protecting your family — and apply that sunscreen this summer!
Hayden CG, Roberts MS, Benson HAE. Systemic absorption after topical sunscreen. The Lancet. 1997;350:863–4.
Janjua NR, Mogensen B, Andersson AM, et al. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans. J Invest Dermatol. 2004 Jul;123(1):57–61.
Janjua NR, Kongshoj B, Andersoon Am, Wulf HC. Sunscreens in human plasma and urine after repeated whole-body topical application. J Eur Acad Dermatol Venereol. 2008 Apr;22(4):456–61.
Krause M, Kilt A, Blomberg Jensen M, et al. Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters. Int J Andrology. 2012:35:424–436.
Schlumpf M, Cotton B, Conscience M, et al. In vitro and in vivo estrogenicity of UV screens. Environmental Health Perspectives 2001;109: 239–244.
The EWG extrapolates data (usually from animal studies, not humans), and uses scare tactics to make us feel like we are hurting our children if we use certain products. What I don’t like is that they ignore actual sound studies that show safety in humans. Their sound bites are alarming and catchy for headlines. I’ve actually seen website titles citing the EWG reading: “
Dr. Jacquelyn Dosal, Dermatologist 