How come when I use SPF 50 I still burn?
First of all, beware of the work “sunblock.” The industry was corrected a number of years ago on the usage of the word block in regard to sun protection as nothing is considered to be a 100% BLOCK of the sun. Secondly, become familiar with two types of sunscreen on the market, chemical and physical. Chemically based sunscreens utilize a chemical ingredient to absorb and diffuse the ultra violet light and heat. Para Amino Benzoic Acid, most commonly known as PABA was the chemical sunscreen of the past that was irritating to the skin and eyes. In 2009 it was banned from the FBA citing DNA damage to human cells by creating Reactive Oxygen Species (ROS) when exposed to UV light. Two of the most prevalent chemical sunscreens of today are avebenzone and oxybenzone. Avebenzone protects against UVA and UVB which makes it a FULL SPECTRUM sunscreen. Often times several chemical sunscreens are combined in one product to give full spectrum protection, but this is not always the case. Physical sunscreens protect against both UVA and UVB making it a full spectrum sunscreen.
The most common physical sunscreens are titanium dioxide and zinc oxide. Physical sunscreens work by physically reflecting and deflecting ultra violet rays away from the area protected. Most often the potential for irritation is almost zero with mineral based sunscreens and quite frequently they offer a soothing component to skin when it becomes heated. About 15 or so years ago when regular use of sunscreen became an important part of an anti-aging skincare program it was much easier to get clients to use the chemical based sunscreens as they had an almost weightless feel compared to the heavy feel of the physical sunscreens of yore. So that the products that “created the magic” in the skin, combined with the heat created in the skin from sun exposure, along with the chemical component in sunscreens was a recipe for a rash to say the least. From there all sorts of new skin issues became prevalent and the need for a less irritating solution for sunscreen was necessary. Cosmetic formulators began using micronized minerals to provide physical protection that had a lighter, more elegant feel and did not increase photosensitivity. These products proved to be less reactive with the ingredients that stimulate cellular renewal in the skin.
Inappropriate application of sunscreens can also leave you wondering why you got burned. Now that you have a brief understanding in the primary difference in the two most common types of sunscreen here is another factor that separates the two. Chemical sunscreens require their application to take place 20 minutes prior to sun exposure. It’s usually stated in the directions on the bottle, but who reads that, right? How many times have you gone out to the pool, set out your chair/towel situation, arranged all of your accutriments, beverage, books, etc, gotten comfortable and then slathered your sun protection on? Or you’re already out on the boat, or you’re already the the baseball game or BBQ? We’ve all done it. Physical sunscreens provide more immediate protection so they don’t require being applied so much in advance, but that being said it’s a great habit to get into.
So let’s just address SPF and what it means… oh it means so many things.
SPF stands for sun protection factor. What does that mean, you ask? It’s something unique to EACH INDIVIDUAL in EACH SITUATION. So what does THAT mean? I like to treat it like a mathematical equation. Let’s work with the SPF of 10 for the sake of ease even though we know we should use an SPF of 15-30 depending (details will follow). So each individual has a certain amount of time they can expose THEIR unprotected skin to ultraviolet rays without burning. Let’s say Suzie Q is a very pale client who burns easily and never really tans. Let’s just say that Suzie Q’s skin would BEGIN to burn in 5 minutes… BEGIN TO BURN. Very important because once a burn has begun, its inflammation cascade is virtually impossible for a chemical sunscreen to protect and prevent further burning and damage. The number in SPF stands for the amount of time someone could tolerate sun exposure without burning. SPF 10 means 10 times the length of YOUR begin to burn time. So from the given numbers, SPF 10 and Suzie Q’s begin to burn time of 5 minutes, we can deduce she would have 50 minutes of sun protection from one application of her SPF 10. That does not a day at the beach make without consequences. If it was the recommended SPF of 30 (recommended by the American Skin Cancer Foundation), it would give Suzie Q 150 minutes worth of protection, which is 2 1/2 hours. This is, of course, if there are no extenuating factors that would increase the intensity of the rays, reflection from water, sand, or snow, if you’re skiing. Her individual begin to burn time is also dependent upon any medications she may be taking that could increase photosensitivity. Certain vitamin supplements can create photosensitivity as well as certain ingredients in over the counter body products. So it’s quite possible that Suzie Q’s being to burn time could be reduced to 3 minutes if, let’s say she’s taking oral antibiotics and out on a boat for the day. The difference those two factors make drop her exposure time down to 90 minutes, and that’s only a “guesstimation.” That’s why reapplication ahead of time is so important. It can make the difference between safe sun exposure and getting burned.
So then the question becomes, “Why can’t I just wear SPF 100 and call it a day?”
The American Skin Cancer Foundation recommend an SPF between 30 and 50. The difference in the numbers represents about a 1% increase in the amount of rays that the product SCREENS. SPF 30 screens up to 97% of ultraviolet rays and SPF 50 screens up to 98%. So not much more protection, but more exposure time without burning. This flip side to this is, is it worth it to have a product on your skin with more chemical ingredients in it that can compromise tissues and cause other health concerns (hormone disruption, look into it if this disturbs you) or just be ware, be educated and be prepared. You could just reapply. I’ve found that most people far overestimate what they think their skin can tolerate, and are also completely unaware of the factors that can impact the effectiveness of sunscreens. It’s not a contest. You’re not a hero because your skin can withstand more exposure than someone else. Understand what your skin can take, where you will be and what you will be doing. One sunscreen does not suit all needs for each individual. I tell my clients they should have a “wardrobe of sunscreens.” Which brings me back around to the beginning of this article. Should you be using a chemical or physical sunscreen on your entire body? It would make sense based on previous points discussed that a physical sunscreen would be the best choice. If it’s best for the face why wouldn’t I choose that type for my body? Physical sunscreens can feel like a coating on your body so it’s a comfort issue and the body skin is more durable skin facial skin. With the increasing incidence of skin cancer among Americans, young Americans at that, it’s important to really get educated on sun protection. As lengthy as this blog entry is, it truly is the only tip of the iceberg on this subject matter.