Footnotes
¹Stern RS. Prevalence of a history of skin cancer in 2007: results of an incidence-based model. Arch Dermatol. 2010 Mar;146(3):279-82.
²https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs
Quick Facts
WHAT IS SPF?
The SPF or “Sun Protection Factor" number tells you how long the sun’s UV radiation would take to redden your skin when using the product exactly as directed versus the amount of time without any sunscreen.
To get the SPF number, a simple formula is used. As an example, the number of minutes it takes a patch of skin to slightly redden when covered in sunscreen is divided by the number of minutes it takes to slightly redden when there is no sunscreen applied. Say it took 120 minutes for skin to redden with sunscreen, and 4 minutes to redden without it. The 120 is divided by 4, which is 30. The SPF is 30.
SPF only gives an indication of how well the sunscreen protects skin against UVB radiation, not the deeper penetrating UVA. If you want protection against both, you’ll need to check that your sunscreen is ‘broad spectrum’. Sunscreens that have this on their label have undergone additional laboratory testing.
CHEMICAL (ORGANIC) VERSUS MINERAL (INORGANIC)
The active ingredients in sunscreens are often divided into two categories:
- Physical sunscreen
ingredients (more correctly known as inorganic sunscreen
ingredients) are zinc oxide and titanium dioxide. - Chemical sunscreen
ingredients (more correctly known as organic sunscreen
ingredients) are everything else.
You can have sunscreens containing only organic filters, only inorganic filters, or a combination of both.
The reason organic (carbon-based) and inorganic (not carbon-based) is a better classification than chemical/physical is that there’s overlap between how they work. Both types work by
absorbing UV and turning it into heat. Inorganic sunscreens also scatter and reflect about
5-10% of the incoming UV.
WHAT DOES BROAD SPECTRUM MEAN?
The number one cause of premature aging is sun exposure. Broad spectrum SPF refers to sunscreens that protect the skin from both UVA and UVB rays. Even with a high SPF (sun protection factor), if a sunscreen isn’t broad spectrum, you won’t be protected from all UVA rays. The current FDA SPF numbering system only identifies the amount of UVB protection a sunscreen product provides, not the amount of UVA protection. For sunscreens to be labeled as broad spectrum, the FDA requires sunscreen products to now go through a battery of tests to prove they protect from all UVA and UVB rays.
It’s important to protect from both types of UV rays because they damage your skin differently.
Think of it this way:
- UVB has a B for “burning” – these rays cause sunburn, aging, and potentially skin cancer
- UVA has an A for “aging” – these rays cause wrinkles and potentially skin cancer (although less than UVB) after repeated exposure. UVA rays make up more than 90% of all UV radiation, and penetrate clouds and glass, year-round.
Why It All Matters
There are no ifs, ands, or buts about it – exposure to UVA and UVB radiation will damage skin. The redness and burning sensation of a sunburn indicates temporary overexposure to UV radiation. If prolonged, unprotected exposure to UV rays can have consequences ranging from premature aging to skin cancer. In fact, one in five Americans will develop skin cancer by the age of 70.¹
Here at Sonrei we're passionate about protecting not only our loved ones, but yours too.
Proud Overachievers
In order to effectively prevent the damaging effects of UV radiation, the American Academy of Dermatology (AAD) has developed the following guidelines for sunscreens², which Sonrei meets and exceeds:
☑ Sun-protection factor (SPF) of at least SPF 30
☑ Water Resistant
☑ Broad Spectrum UVA and UVB Protection
Apply Liberally
The recommended amount of sunscreen per application for the average person is 1 fluid ounce.
A simple way to remember how much sunscreen to apply is imagine the amount of sunscreen that would fit in a shot glass or the size of a golf ball.
Sunscreen should be applied 15 minutes before sun exposure and reapplied after 80 minutes of swimming or sweating, immediately after towel drying, and at least every 2 hours.
For all you fellow parents, we recommend inquiring with your doctor before using sunscreen on your little ones under 6 months of age.
When, Where, Why
Areas nearer to the equator and at higher elevations experience more UV radiation, as UV rays have less distance to travel through the atmosphere to reach the ground, which means a lower likelihood they'll be absorbed by the ozone layer and atmospheric aerosols.
Ultraviolet radiation is strongest between 10am and 4pm during late spring, summer, and early fall for the same reason – UV rays contend with less of the atmosphere at these times and seasons.
Winter Wonderlands
Just because it's winter or the weather is cloudy doesn't mean you're safe from UV radiation, so make your sun protection habits year-round. Some types of cloud cover even increase exposure to UV rays because they return rays reflected from the ground back towards the surface.
On that note, snow and a variety of other surfaces will reflect many of the UV rays that reach them. In addition to wearing Sonrei sunscreen, sunglasses rated for 100% UV protection and a wide-brimmed hat will help protect your skin from reflected UV rays.
Skin Cancer Spot Check
All adults should make it a habit to check their skin and moles every 3 months. If you're at risk for developing skin cancer, have a board-certified dermatologist examine your moles at least once a year.
Melanomas can develop in between visits to your skin cancer doctor, therefore you should know how to check your own skin and moles.
If you find any new or suspicious spots on your skin or any spots that are changing, itching, or bleeding, make an appointment to see a board-certified dermatologist.
To learn more about skin cancer and find a free skin cancer screening near you, visit SpotSkinCancer.org.
