Sunscreens work by absorbing (organic sunscreens), or reflecting and scattering UV light (physical sunscreens).
SPF stands for sun protection factor. It is the measure of UVB protection offered by a product and ranges from 2 to 80.
In order to understand how SPF is measured, we have to clarify a common misconception. Many people believe that SPF is simply a measure of protection from the sun. However, SPF is in fact a time-compared measure relating to whether or not you’re wearing sunscreen. More specifically, SPF is determined by the amount of time it takes UVB rays to redden your skin without wearing sunscreen compared to the amount of time it takes your skin to turn red when you are wearing sunscreen.
An SPF of 60 does not give you twice as much protection as an SPF of 30. In today’s world it more accurately reflects what percentage of the sun’s rays are blocked for as long as the sunscreen is working. Since most sunscreens need to be reapplied every 2 hours, we view SPF as a useful but not definitive measure. For instance, an SPF of 30 will block 97% of the sun’s UVB rays, while an SPF of 50 will block 98%. Not twice the protection, especially since it must be reapplied. And SPF does not take into account UVA protection, which is another issue.
The FDA and EWG (Environmental Working Group) advise that you should use a sunscreen with an SPF of at least 15.
The difference in sunscreens of similar SPF’s has to do with the presence of varying active and inactive ingredients. The active ingredients are what protect you from the sun. The inactive ingredients are what give a particular sunscreen its characteristics: water resistant, non-pore clogging (non-comedogenic), etc.
When choosing the appropriate SPF, you should take into consideration certain aspects about yourself. This includes your skin tone, how active you are in the sun (do you play outdoor sports?) and how much time you spend in the sun on any particular day.
Melanin is a chemical pigment our skin produces which absorbs ultraviolet radiation. It is natural and DNA-dependent. The amount of melanin in our skin accounts for different skin tones: the more melanin in your skin, the darker your skin will be. Although referred to as “natural sunscreen,” melanin alone cannot completely protect us from the sun’s damaging rays.
However, we know that the more melanin present in your skin (i.e. the darker your skin), the less likely you are to burn or redden as quickly as those with less melanin (lighter skin). Since SPF is a comparison of the time it takes skin to redden while wearing sunscreen as opposed to not wearing sunscreen, we can conclude that the darker your skin, the lower your SPF requirement.
The chart below provides SPF recommendations based on skin tone:
In addition to skin shade, you should consider how active you are in the sun. Please note that, depending on how active you are, you may need a higher SPF than what is listed above.
If you play sports, you are more inclined to sweat, causing your sunscreen to wear off. Engaging in outdoor activities for longer periods of time require a higher SPF. Remember that applying sunscreen with an SPF 40 allows you 40 times as long in the sun before your skin reddens compared to the amount of time without that particular sunscreen.
It is important to reapply your sunscreen every 80 minutes following your first application to maximize protection. Be sure to use UVA/UVB Broad-Spectrum sunscreen to ensure you maximize protection of your skin. MDSolarSciences recommends our broad-spectrum, water resistant, SPF 40 Ultra-Sport Stick for active adults and children.
UPF stands for ultraviolet protection factor.
Like SPF, UPF is also measured as a time-comparison. UPF is determined by the amount of time it takes ultraviolet (UV) rays to redden your skin without wearing sun-protective clothing vs. to the amount of time it takes your skin to turn red when you are wearing clothing that is sun-protective. For instance, if you’re wearing a wetsuit with a UPF of 50, it will take your skin 50 times as long to turn red had you not chosen to wear it.
SPF and UPF are calculated differently. UPF is measured by a series of factors that take into account the weight, interlace, shade of color, percentage of skin coverage and fabric form of the clothing.
Clothing with a UPF of 50+ blocks 98% of UV rays and is considered the best in sun protection.
MDSolarScience’s sun-protective apparel are all UPF 50+.
It is important to note that, while wearing sun-protective clothing you must also wear sunscreen on parts of your body that will be exposed to the sun. Apply broad-spectrum sunscreen to your face and hands and feet—sometimes arms and legs (depending on sleeve and pant length).
We recommend wearing UPF 50+ sun-protective clothing in order to optimize your shield against ultraviolet radiation.
You would need to live inside a cave without any light to get complete sun protection. And you should not try it. Vitamin D and many other processes, such as hormonal regulation, depend upon exposure to natural sunlight. Practicing safer fun in the sun should balance the body’s natural need for sun exposure, your psychological need for sunshine, your physical need to be outdoors with a thoughtful protection plan to minimize your chances of sun damage by employing only dermatologist recommended sunscreens.
The interactions in marine biology are so complex that it is impossible to say for sure what effects the numerous chemicals in the environment have on the marine environment and specifically on coral reefs. MDSolarSciences seeks to eliminate any sunscreen actives or additives that have been implicated, such as octinoxate. Our philosophy is that if we can do without it, it is better to leave it out, especially if there is any question.
No since 80% of UV radiation can pass through the clouds. Some of the worst burns occur on cloudy days because we think we are not being exposed to the sun. please include the link to “Year-round benefits of sunscreen”) here.
It is probably better to avoid the intense sun in children less than 6 months of age. Although sunscreens may be better than nothing, the unknown allergic potential of infants, the unknown safety and absorption of many of the active and inactive ingredients makes it safer to just use sun protective clothing, hats and good sun avoidance. We recommend you ask your pediatrician for guidelines.
Solar radiation consists of a continuous spectrum of wavelengths that reaches the earth’s surface. In sun damage, we are concerned with UVA, UVB and UVC. They are all at the end of the visible light spectrum (Red, Yellow, Blue, Purple, etc.).
Ultraviolet radiation is described as UVA, UVB and UVC rays. The UVA region of the UV spectrum extends from 320nm to 400nm (a measure of the size of the light wave).
UVA is thought to contribute to photoaging (lines, brown spots and wrinkles) and is also thought to play an adjunctive or auxiliary role in the creation of skin cancers.
The UVB rays produce sunburn, skin cancer and photo aging. Their spectrum is 290 nm to 320 nm.
The UVC region of the UV spectrum extends from 200nm to 290nm. UVC is absorbed by the ozone layer of the stratosphere and does not reach the surface of the earth. This may change with the depletion of the ozone layer and UVC may become more important as time goes on.
