Jun 24 2013

How to choose a sunscreen

Best Sunscreen Mystic, CT

Why You Should Wear Sunscreen

Sunlight contains ultraviolet radiation which is absorbed by skin cells. The effect of this environmental exposure on your skin cells is to increase your risk of developing both skin cancer (melanoma, basal cell cancer, and squamous cell cancer) and signs of premature skin aging (brown spots, wrinkles, blotchy skin, rough skin texture). Sunscreens have a protective impact on your skin in that it can decrease your risk of developing skin cancer and premature skin aging. 

That is why choosing a sunscreen -- choosing the best sunscreen -- is important. Over time, we have learned that sunlight is composed of many different wavelengths in both the visible and non-visible spectrum of light. Two important ranges of light which interact with skin cells inculde UVA (ultraviolet A) and UVB (ultraviolet B).

Ultraviolet Light A - UVA

UVA is generally called the "aging rays". UVA penetrates deeply into the skin layers, thus damaging collagen and cells in the dermis or second layer of the skin. UVA rays can pass through glass (such as windows in offices, homes, and cars) and are not affected by weather or altitude. UVA is present all day and everyday of the year and is 50 times more prevalent than UVB rays. UVA rays increase your risk of skin cancer.

best sunscreen image

Ultraviolet light B - UVB

UVB is generally called the "burning rays". UVB mostly affects the outer layer of the skin, called the epidermis, --leading to sun burns and sun tans. UVB varies with time of day, season, altitude, and geographic location.

The best sunscreens block both UVA and UVB from being absorbed into your skin.

How Do Sunscreens Work

There are two categories of sunscreen ingredients: chemical and physical. Both prevent the sun's rays from being absorbed into your skin cells. Long or short term unprotected exposure to UVA and UVB light can cause your skin cells to not function normally--leading to skin cancer and sun damage.                                

best sunscreen imageChemical sunscreens:

  • absorb the ultraviolet rays, thus preventing the light from interacting with and damaging your skin cells
  • are absorbed into your skin
  • are changed and degraded by sunlight--so they lose their protection factor within a few hours
  • examples: avobenzone, aminobenzoic acid, cinnamates, oxybenzone, octocrylene

Physical sunscreens:

  • reflect the ultraviolet rays, thus preventing the light from interacting with and damaging your skin cells
  • stay on the skin's surface; are not absorbed
  • are not changed or altered by sun-exposure, and therefore are more "photo-stable". They are inert physical particles
  • are natural physical molecules and therefore do not irritate sensitive skin--they are not  chemicals
  • examples: zinc oxide, titanium dioxide (both now micropulvarized into nano-particles so they do not look "white" on the skin.

The best sunscreens have exclusively, or at least partially, nanoparticle physical blockers. Data affirm that nanoparticles of the size and molecular weight used in sunscreens cannot pass through the skin, are not absorbed into skin cells, and are not absorbed into any other body system including the bloodstream.

What are the Best Sunscreen Ingredients

Broad Spectrum (UVA + UVB protection)

The best sunscreen ingredients therefore protect our skin cells from both UVA and UVB.

best sunscreens imageZinc oxide has the widest protection spectrum covering both UVA and UVB rays

Titanium dioxide is also a physical sunscreen with a wide UVA and UVB protection spectrum

Chemical sunscreens such as oxybenzone, octocrylene, octinoxate, homosalate, and others provide a more narrow protection for both UVA and UVB.

At Coastal Dermatology, we offer different types of sunscreens to help you chose the best sunscreen for you:

  • oil free and light weight for acne prone skin or for patients who dislike that heavy/greasy feel to a sunscreen
  • chemical free and do not cause irritation to sensitive skin, and are safe for children
  • broad spectrum to allow for maximum UVA and UVB sun protection
  • special lip and around the eye products that are natural, minerals only, and non-irritating

What does SPF mean

SPF, or sun protection factor, refers to UVB protection ONLY. SPF refers to how well a sunscreen protects your skin from exposure to and absorption of  a certain amount of UVB sunlight. For example, an SPF 2 will block 50% of the UVB rays, an SPF 15 will block 94% of the UVB rays, and an SPF 30 will block 97% of the UVB rays.

FDA Ruling on Sunscreens

The FDA created a "ruling" for sunscreens to help consumers better compare sun-protection products and determine which provide adequate ultraviolet coverage. There are four main points which are now required of all sunscreen labeling:

  • broad spectrum SPF means a sunscreen has adequate UVA as well as UVB protection and is an SPF 15 or greater
  • only broad spectrum SPF sunscreens with a rating of 15 or greater can claim to reduce the risk of skin cancer and premature skin aging
  • sunscreens cannot claim to be waterproof, sweat-proof, or be a sunblock as these words overstate their effectiveness. Sunscreens cannot claim to provide sun protection for more than two hours without reapplication
  • water resistance written on the label indicates the product remains effective for 40  to 80 minutes while swimming or sweating

How to Prevent Sun-damage & Chose the Best Sun Protection

So the best sunscreen is not a certain brand. Rather, it is a combination of reading the ingredients on the label to select a product that clearly states it provides both UVA and UVB protection,  is at least an SPF 15 and preferably best sunscreen imagean SPF 30, and then also carries the other qualities you are looking for (oil free, for sensitive skin, or otherwise). Some people prefer sprays for ease of application and less heavy. Other people prefer sports gels as they also are less heavy. There are sticks for lips, under eyes, and ears. These products can be applied without getting your hands slippery. The best approach for chosing the best sunscreen for you is to follow the guidelines above to make sure your product provides good sun protection, select a formulation that you like--then you will use it, and reapply every 2-3 hours.

Other ways to protect your skin from sun-damage include:

  • limit your total time in direct sunlight
  • avoid being in direct sunlight between 10 AM and 2 PM
  • wear special lightweight SPF clothing to further protect your skin
  • use a hat and sunglasses
  • reapply sunscreen every 2-3 hours

How to Treat Sun-damage


None of us have the same skin we had when we were younger. Over time, and exposure to the sun, we develop brown spots, wrinkles, thickened skin, rough skin texture, and blotchy skin tone. Sunscreen can prevent further sun-damage. Certain skin care products have data from medical studies that they can reduce the sign of aging. Active ingredients to look for include:

  • vitam A (retinols)
  • vitamin C (l-ascorbic acid)
  • growth factors
  • alpha hydroxy acids

Non surgical no downtime skin treatments can treat and reduce the signs of early skin aging--making skin look younger and more healthy. Lasers can removal spider veins and brown spotschemical peels can soften skin texture; Accent radiofrequency can tighten sagging skin; laser skin resurfacing can decrease fine lines and wrinkles. Botox and Dysport can soften areas creased from constant squinting, frowning, or smiling. Fillers such as Restylane or Juvederm can soften facial folds and wrinkles. As the technology for sunscreens has dramatically improved over the past decade, so has the procedures for treating sun damage. There are now many options for both preventing and treating sun-damaged skin.

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Coastal Dermatology: Daniella Duke, MD

Phone: (860) 245-0000
Fax: (860) 245-0610