Sunscreens, SPF and the Importance of Being “Sun Smart!”

Joseph R. Anticaglia MD
Medical Advisory board

Years ago, while walking on the boardwalk in Atlantic City, I noticed stretches of women sitting on benches facing the ocean in their bathing suits. They held metal-like reflectors under their chins while gathering the noonday sun and aiming it at their faces. Today, women at the beach or pool are protecting themselves from the sun. They wear broad rimed hats, use sunglasses, sit under umbrellas and smear sunscreen on their skin from the forehead to their toes.

Although vitamin D is the sunshine vitamin, too much sun exposure has been linked to aging skin and skin cancer, especially melanoma. Dermatologists for many years have cautioned about the dangers of excessive sun exposure and advocated for the proper use of sunscreens.


Sunscreens are essential tools in the fight against skin cancer. They’re products that come in different forms; such as creams, lotions and ointments. They’re for external use only and the goal is to limit your exposure to the sun’s rays, prevent sunburn and reduce the incidence of skin cancer. Some sunscreens, when applied to the surface of the skin, have chemical ingredients which absorb ultraviolet and visible sun rays. Others physically sit on the surface of the skin blocking (sun block) UV rays from reaching the skin.

broad spectrum sunscreen protects you from both ultravioletA (UVA) and ultravioletB (UVB) sun rays. The “B” rays (think burning) damage the outer skin or epidermal layer causing redness and sunburn.

Amab Chanda Three layers of skin

The “A” rays (think aging) damage the dermis, the layer of skin beneath the epidermis. Within the dermal layer are structures that give the skin it flexibility and strength. If the skin is unprotected from “A” rays, over time the skin will wrinkle, become less flexible, lose strength and the person will appear older. In addition, there is a greater risk of developing skin cancer.


The sun protection factor measures the ability of a sunscreen to protect you from redness and sunburn due to UVB rays. Sunscreens are given a SPF number and rated according to how well the product protects you from the sun.

SPF 15 means that the product only allows 1/15 of the sun rays to penetrate the skin; this is the equivalent to 93% protection from the sun rays when applied properly. But what does this really mean? From a practical standpoint, a person wants to know, “How many minutes can I stay in the sun with a SPF 15 or 30 before my skin starts to turn red?

For instance, if it takes you 20 minutes to get sunburned with no sunscreen protection, SPF 15 allows you to remain in the sun 15 times longer or for 300 minutes (20 minutes x 15 = 300 minutes). SPF 30 allows you to remain in the sun 30 times longer or 600 minutes (20 minutes x 30 = 600 minutes).

In general, a product with a SPF above 30 is of questionable value.

  • SPF 15 blocks 93 percent of UVB rays
  • SPF 30 blocks 97 percent of UVB rays
  • SPF 50 blocks 98 percent of UVB rays
  • SPF 100 blocks 99 percent of UVB rays

Before using sunscreens, discuss the ingredients of the product with your pharmacist and physician. Review your medical history for allergies and the possibility of drug, food or alcohol interactions. Infants under 6 months of age should not be exposed to sun. Older children should be protected with at least SPN 15 when exposed to sun.

People are at a greater risk to develop skin cancer if they have pale skin, blond or red hair or if they or a family member have been treated for skin cancer.

Special protective precautions should be taken at the beach, pool or ski slopes, since UV rays can bounce off sand, water and snow. Furthermore, take into consideration that the higher the elevation (mountains), the greater the risk of skin damage from UV rays. Also, minimize noontime exposure to UV rays.

The most common cause of skin cancer is from exposure to ultraviolet rays from the sun or tanning beds. Over the years skin damage accumulates leading to melanoma, basal cell and squamous cell skin cancers. What follows are sun smart takeaways to reduce skin cancer.


  • Be “sun smart” if you’re working, playing or enjoying the outdoors, protect your skin from the sun
  • Seek shade especially during midday hours
  • Wear sunglasses, a hat and protective clothing to shield the skin
  • Sunscreens fight skin cancer
  • Use a broad spectrum sunscreen with a SPF 30 to protect exposed skin
  • Apply sunscreen about 30 minutes before being exposed to the sun
  • Use sun protection even on cloudy days
  • Sunscreen must be reapplied every 2 hours and after sweating, swimming or toweling off.
  • Do not use tanning beds, booths or lamps. There is no such thing as a safe tan
  • Dark skin people need to protect themselves against UV rays.
  • Be mindful of sun sensitizing medications- for example, ciprofloxacin. diphenhydramine (Benadryl)
  • Infants under six months of age should not be expose to UV rays
  • Routinely check your skin

UVB rays, in small amounts, help our body make vitamin D, which we need to build strong bones. However, prolonged exposure to UV rays damages the skin and leads to skin cancer. Often overlooked but very important is to use sunscreen on your lips.

It is estimated that one in five Americans will develop skin cancer in their lifetime. Sunscreens work by absorbing, scattering or reflecting UV rays. They prevent sunburn, lower the risk of premature aging and reduce the danger of skin cancer.


  1. Paller AS et al. New Insights About Infant and Toddler Skin: Implications for Sun Protection. Pediatrics; July, 2011
  2. CDC; Sunscreen: How to Select, Apply, and Use It Correctly; Sunscreen; April 26, 2002
  3. American Academy of Dermatology; Sunscreen FAQs; 2018
  4. U. S. Food and Drug; Tips to Stay Safe in the Sun: From Sunscreen to Sunglasses
  5. Swanson, David; Sun Protection; 7/25/2017


Organic sunscreens are carbon-based compounds that absorb UV rays that are released as heat.

Inorganic sunscreens shield the skin from UV rays by reflecting the rays away from the skin. They use compounds that cover and protect the surface of the skin, such as, zinc oxide and titanium dioxide.

This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.