The Down and Dirty About Sunscreen and SPF- Michele Westendorf, NP-C

1 in 5 Americans will develop skin cancer in their lifetime and the best way to prevent that is sun protection.
What does SPF really mean?
SPF stands for sun protection factor and it tells you how long it would take the sun to redden your skin when using the product versus the amount of time you could spend in the sun without any protection. So if your skin would normally burn after 10 minutes of unprotected exposure, using a SPF 15 would allow you to stay in the sun without burning for approximately 150 minutes (a factor 15). This really a rough estimate and more relevant use of SPF is actually a measure of the protection from UVB exposure. The SPF scale for UVB % is not linear. SPF 15 blocks 93% of UVB rays and SPF 30 blocks 97% of UVB rays and SPF 50 blocks 98%of UVB rays. It is important to note that NO SPF blocks 100% of UVB rays. Furthermore, the actual effectiveness of sunscreen is directly related to the AMOUNT of sunscreen applied. The general recommendation is for 2mg per cm squared which translates to roughly 1 oz or 1 shot of product for the entire body.
What are UVA rays?
UVA rays are considered the long wavelengths and although they are less intense than UVB, they are more prevalent and are present with equal intensity during all daylight hours throughout the year and can penetrate clouds and glass. UVA rays penetrate the skin more deeply and have long been known to play a major part in tanning and photoaging (wrinkles and brown spots); furthermore, recent studies have proven that UVA damages the skin cells called keratinocytes in the basal layer of the epidermis which is where most skin cancers occur. Basal cells and squamous cells are types of keratinocytes. UVA is the primary emission of tanning beds and these high pressure lamps can emits doses 12 times stronger than the sun. People who use tanning beds are 2.5 times more likely to develop SCC and 1.5 times more likely to develop BCC. Tanning bed exposure also substantially increases melanoma risk.
What are UVB rays?
UVB are the short wavelength rays and the major cause of skin reddening and sunburn. It damages the skin’s more superficial epidermal layers. It plays a key role in the development of skin cancer and a contributing role in tanning and photoaging. It does not penetrate glass and its intensity varies by season, location and time of day. UVB rays can burn and damage the skin year round, especially at high altitudes and on reflective surfaces such a snow, sand, water and ice, which can bounce back up to 80% of the rays meaning they damage the skin twice.
What is the reality about sunscreen use?
The average American applies 20-50% of the recommended amount. Taking into account real human behavior some recent studies have shown that using a very high spf (70+) along with early re-application (1hr after sun exposure) have been shown to partially offset the amount of sunscreen people actually apply. Not to mention how hard it is to get kids to reapply and if they are wet and covered in sand it becomes even harder. SPF clothing is generally easier than wrestling your kids for reapplication.
Which sunscreen should I use?
The sunscreen should be labeled as broad-spectrum which means it protects against UVA and UVB, SPF 30 or higher and water resistance if you are planning on sweating or swimming. The recommendation is to apply 1oz 15 minutes before sun exposure and 2 hours of sun exposure. The recommended type of sunscreen is one that you will actually use. That being said there are two broad categories: chemical and physical. Chemical sunscreens work like a sponge and absorb the sun’s rays. The most commonly used types are: oxybenzone, octisalate, octocrylene, homosalate and octinoxate. The advantage of these formulations is that they tend rub in more easily without leaving a white residue. Physical sunscreens work as a shield and sit on the surface of the skin and deflect the sun’s rays. They contain zinc oxide and/or titanium dioxide. If you are using a chemical sunscreen on your face make sure to apply it before make up or lotions and the physical/mineral sunscreen can be applied on top of or under makeup or lotions.
I have heard that chemical sunscreens are bad for you. Is that true?
The US Food and Drug administration have approved the active ingredients in both types of sunscreen as safe and effective. Oxybenzone is the most commonly criticized chemical sunscreen because of studies done on rats where the rats were fed the oxybenzone, which led to hormone disruption. The amount fed to the rats was equivalent what would take a person 277 years of daily application on face, neck, hands and arms. Another concern is the recent law that Hawaii passed banning oxybenzone due to detrimental risk to coral. This law was based on one study and subsequent studies have shown that oxybenzone water level were much lower than the concentration used in the study. Overall, the risk associated with sunscreen use appear to be very, very low.
I have also heard sunscreens can cause skin cancer. Is this true?
Absolutely not! The conclusions have been misappropriated from studies where individuals who used sunscreen had a higher risk of skin cancer. The part of the story that is missing is that these were also the individuals who used sunscreen when traveling to sunnier climates and sunbathing which means that it was the high amount of sun exposure and not sunscreen that elevated their risk of skin cancer. Remember, there is no sunscreen that blocks 100% of the UV rays and tan is a visual reminder that you skin has been damaged. Furthermore, we have many many studies showing that people who do not use sunscreen have a much higher rate of skin cancers.
It is so hard to get sunscreen on my kids (and husband/ partner). Do the spray sunscreens work?
I understand the appeal of the spray sunscreen. It is without question easier to spray sunscreen on than apply a cold lotion. That being said, the current FDA regulations on testing and standardization do not apply to spray sunscreen. It is also important not to inhale the products or near heat or open flame or while smoking. It is also important to use enough sunscreen to thoroughly cover all exposed skin and to rub the product in. I have seen a large number of burns on patients who thought they were protected with spray sunscreen. I generally recommend the stick or brush on sunscreens versus the spray on, but as I said earlier the most effective sunscreen is the one that you will actually use. So if it is a choice between spray on sunscreen and no sunscreen then spray away (but please do not forget to rub it in).
What can I do to protect my baby from the sun?
Ideally, babies younger than 6 months should not be exposed to the sun but here in sunny California that is a very tall order. Try to provide infants with physical protection such as shade along with SPF clothing, long sleeves and pants and wide brimmed hat and sunglasses if you are going to be out in the sun. Infants have a low fluid reserve so it is much easier for them to get overheated and dehydrated. Once infants are over 6 months old a broad-spectrum sunscreen with PSF 30+ can be applied. Sunscreens that use zinc oxide or titanium dioxide are preferred as they are less likely to irritate their sensitive skin and it should be reapplied every 2 hours. Furthermore, the regular use of broad-spectrum sunscreen with SPF 30+ has been shown to reduce the amount of nevi (moles) formed on children and adults. Having a large number of moles has been shown to be a strong predictor of melanoma.
How long is sunscreen good for?
The FDA requires all sunscreens require their original strength for at least 3 years. Some bottles have expiration dates and if they don’t I recommend writing the date of purchase on the bottle so you know when to discard it. There are also visible signs that sunscreen is past its effective date such as a change in color or consistency.
Do you personally really wear sunscreen everyday?
Many of you know, I am a triathlete, which means I spend a large amount of time training outside so I understand the irritation and aggravation of sun protection. I personally prefer the mineral sunscreens for my face, neck, chest and hands. I pay attention to the UV index and the only time I train without sunscreen is when it is dark. I wear SPF clothing for training especially the long sleeve shirts. Ideally, my training happens in the early morning or evening but when reality and my personal preferences do not align I wear zinc paste mineral sunscreen on my face, neck, chest, and hands and long sleeved SPF shirts and long pants. My personal preference is equestrian shirts because they have a collar, netting and vetting to help minimize getting overheated. And if I have not done laundry then I use the Elta MD UV Sport SPF 50 for all other parts of my body. It is zinc and octinoxate and octisalate blended together so it’s easy to rub in and makes me sweat less than other types.
Okay, Okay you have convinced me. What sunscreens do you recommend?
If you have sensitive skin, acne or want a light feeling sunscreen the Elta MD sunscreen UV clear or tinted is an excellent product and is mineral based. For sensitive skin I recommend sticking with mineral sunscreens. Neutrogena makes a sheer zinc which rubs in well.
Priori Tetra fx 251- this is what I wear daily. It has a universal tint, broad spectrum mineral sunscreen with SPF 50, DNA repair enzymes which help reverse both aging effects from the sun and early basal cell skin cancers, antioxidants to protect the skin along with blue light protection.
Colorscience Total Protection Face Shield- I like this product because is gives your skin a dewy glow while providing broad spectrum mineral protection with SPF 50 and water resistance. It is lightly hydrating, protects against infrared radiation, pollution and blue light exposure.
Colorscience Total Protection Brush On Shield- I carry this in my car and on my bicycle. Its great for reapplication, brushing on kids, down hairline parts. It is a powdered mineral sunscreen that is broad spectrum SPF 50 and water resistant.
Colorscience Total Eye 3in1- This is another product I wear daily. It is a mineral sunscreen with SPF 35 that can be applied right up to your lash line. It helps improve dark circles and puffiness while protecting your delicate eye area from photoaging (fine lines and wrinkles).
My last note is to please make sure you apply sunscreen to your ears and your lips as these areas are often forgotten.

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