No cancer, including melanoma, can ever be prevented with 100% certainty. Some risk factors for melanoma, such as skin type and family history, cannot be changed. Sometimes melanoma may develop despite your best efforts to prevent it.

The good news is that the risk factors for melanoma are well known. Since the primary risk factor for melanoma is exposure to ultraviolet (UV) radiation, learning how you can protect yourself from UV radiation can help you reduce your risk of melanoma.

Sun Safety

Top 5 Ways to Protect Yourself from Harmful UV Radiation

  • Stay indoors or look for shade in the middle of the day when UV radiation is strongest, usually between 10am and 4pm.
  • Seek shade under an umbrella, tree, or other shelter to seek relief from the sun.
  • Plan outdoor activities for the early morning or late afternoon, when UV radiation is typically one third of what it is at midday.
  • Cover up with long-sleeved shirts, long pants, wide-brimmed hats, and sunglasses to offer the best protection against UV radiation.
  • If you can’t cover up completely, be sure to use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30 on all exposed skin.

American Cancer Society Sun Protection Message

Slip! Slop! Slap! Wrap!

To help you remember some of the basic sun safety tips, the American Cancer Society has adopted this simple message created in Australia: Slip! Slop! Slap! Wrap!

SLIP on a shirt. Clothing is one the most effective protections against UV radiation. Keep the following tips in mind:

  • Long-sleeved shirts and long pants offer the best protection.
  • A tight weave, such as the cotton knit of a t-shirt, offers more protection than a loose weave. For a rough idea of a fabric’s ability to block UV rays, hold it up to the light. Fabrics that allow more light to come through will probably let more UV radiation through as well.
  • Dark colors are more absorbent and less reflective than light colors and so offer better protection.
  • Dry clothing is more protective than wet. A wet t-shirt offers protection equivalent to about an SPF of only 4.

SLOP on sunscreen. Sunscreens absorb, reflect, or scatter most but not all UV rays before they can penetrate the skin. Look for sunscreens with the following features:

  • Broad-spectrum protection. Broad-spectrum sunscreens protect against both UVA and UVB radiation. Look out for sunscreens containing zinc oxide, titanium dioxide, Mexoryl, and avobenzene in particular.
  • A sun protection factor (SPF) of at least 30. SPF measures how long a product protects the skin from UVB rays before it starts to burn, compared with how long it takes to burn without protection. If you start to burn in 10 minutes without protection, using an SPF 15 sunscreen theoretically will prevent you from burning 15 times longer, or about 2.5 hours. An SPF of 15 blocks 93% of UVB rays. SPFs of 30 and higher block 97% of UVB rays and are suggested for people who are sun-sensitive, have skin cancer, or are at a high risk for developing skin cancer.
  • Make sure you put on an adequate amount of sunscreen and reapply every 2 to 3 hours and more regularly if you are swimming. The number one cause of people sunburning even when they have sunscreen on is a failure to reapply it after several hours.
  • A “waterproof” feature, if you will be sweating or swimming.
  • A valid expiration date. Sunscreen without an expiration date has a shelf life of no more than 3 years. Some sunscreen ingredients can degrade and lose their effectiveness over time, particularly when exposed to extreme temperatures.

SLAP on a hat. For the most protection, wear a hat with a brim wide enough to shade your face, ears, and the back of your neck. Look for hats made of tightly woven fabrics, such as canvas. Avoid loose weaves, particularly straw hats with holes that allow sunlight through. If you prefer to wear a baseball cap, make sure to protect your ears and the back of your neck. Wear clothing that covers those areas, use sunscreen with at least SPF 30, or stay in the shade.

WRAP on sunglasses. Sunglasses protect your eyes, your eyelids, and the delicate skin around your eyes from UV rays. They also reduce the risk of cataracts.

  • The American National Standards Institute (ANSI) requires that sunglasses block a minimum of 50% of UVA and 70% of UVB rays. Glasses labeled “meets ANSI requirements” or “UV absorption up to 400 nm” provide 99% to 100% protection from UVA and UVB rays. Glasses labeled “cosmetic” block 70%. Avoid buying sunglasses that carry no label.
  • Darker sunglasses or polarized lenses don’t necessarily offer more UV protection. UV protection is provided by a chemical that makes up part of the invisible coating on the lenses, regardless of how dark they are.
  • Wraparound sunglasses prevent UV rays from entering your eyes from the sides.
    Don’t buy “toy sunglasses” for your children. Look for the same UV protection in children’s sunglasses as you would in adult glasses.

What about Vitamin D?

It’s true that vitamin D is important for health; that some people may be deficient. However, because of the risks associated with UV radiation, the National Institute of Health recommends that you focus on getting vitamin D from food or supplements rather than the sun.


UV Index

The UV Index was designed to help you make informed decisions about how much time you should spend in the sun and what protection you should use.  It tells you how strong the sun’s UV rays will be. The higher the UV Index, the greater the strength of the sun’s UV rays and the faster you may burn.

The index predicts the risk of UV overexposure on a scale of 0 (minimal risk) to 11+ (very high risk). The forecast considers latitude, elevation, weather conditions, time of year and the ozone levels in your region. The index is based on a type 2 skin type (fair skin, burns easily, tans minimally)

The chart below shows the levels of the UV Index and what you should do to protect yourself.



UV Index 0-2 means minimal danger from the sun’s UV rays for the average person. Most people can stay in the sun for up to 1 hour during peak sun (10am to 4pm) without burning. However, people with very sensitive skin and infants should always be protected from prolonged sun exposure.

UV Index 3-5 means low risk of harm from unprotected sun exposure. Fair skinned people however, may burn in less than 20 minutes. Wearing a hat with a wide brim and sunglasses will protect your eyes. Always use a sunscreen with an SPF of at least 30, and wear long-sleeved shirts when outdoors.

UV Index 6-7 means moderate risk of harm from unprotected sun exposure. Fair skinned people however, may burn in less than 20 minutes. Wearing a hat with a wide brim and sunglasses will protect your eyes. Always use a sunscreen with an SPF of at least 30, and wear long-sleeved shirts when outdoors. Remember to protect sensitive areas like the nose and the rims of the ears. Sunscreen prevents sunburn and some of the sun’s damaging effects on the immune system. Use a lip balm or lip cream containing a sunscreen. Lip balms can help protect some people from getting cold sores.

UV Index 8-10 means high risk of harm from unprotected sun exposure. Fair skinned people however, may burn in less than 10 minutes. Minimize sun exposure during midday hours of 10am to 4pm. Protect yourself by liberally applying a sunscreen of at least 30. Wear protective clothing and sunglasses to protect the eyes. When outside, seek shade. Don’t forget that water, sand, pavement and glass reflect UV rays even under a tree, near a building or beneath a shady umbrella. Wear long sleeved shirts and trousers made from tightly-woven fabrics. UV rays can pass through the holes and spaces of loosely knit fabrics.

UV Index of 11+ means very high risk of harm from unprotected sun exposure. Fair skin people however, may burn in less than 5 minutes. Outdoor workers and vacationers who can receive very intense sun exposure are especially at risk. Minimize sun exposure during midday hours of 10am to 4pm. Apply SPF 30+ sunscreen every 2 hours. Avoid being in the sun as much as possible and wear sunglasses that block out 99-100% of all UV rays (UVA and UVB). Wear a cap or a hat with a wide brim which will block roughly 50% of UV radiation from reaching the eyes.

About Ultraviolet Radiation

  • Is an invisible form of light and energy given off primarily by the sun
  • Can penetrate the upper layers of our skin
  • Is absorbed by DNA and can change its structure (causing mutations)
  • Some DNA changes can be corrected–if not, changes can lead to unchecked cell growth (ie, cancer)
  • If you are exposed to frequent and intense UV radiation, you are exposed to one of the major risk factors for melanoma.

There Are 3 Types of UV Rays:

  • UVA (Long wavelength)
    • Penetrate deeply
    • Associated with wrinkling / leathering of skin
    • Makes UVB-induced damage worse
    • Directly stimulates skin cancers
  • UVB (Medium wavelength)
    • Burning waves
    • Primary cause of sunburn
    • Main cause of basal cell and squamous cell carcinoma as well as cause of melanoma
  • UVC (Short wavelength)
    • Absorbed by ozone layer
    • Not thought to induce skin cancer

Although both UVA and UVB can cause damage, the skin reacts differently to each one.

Comparison of UVA and UVB



Less potent, but constitutes the bulk of UV radiation reaching the earth More potent, leading to more DNA damage and cancer risk
Long-term: damage to dermis leads to thinning and aging of the skin Short-term; epidermis releases chemicals leading to reddening / swelling (early signs of sunburn)

Long-term: repeated exposure leads to injury and aging skin

Can penetrate glass Cannot penetrate glass


Dangers of Outdoor Tanning

It is NOT true that you have to burn in order to tan. In fact, trying to “tan through the burn” is a dangerous practice that only causes more skin damage. Tanning and burning are both forms of skin damage caused by overexposure to UV radiation.

  • A tan develops only after so much damage has occurred to one’s skin cells that the damaged skin tries to protect itself by sending signals to the melanocytes to produce more melanin, the pigment that darkens your skin. As the melanocytes produce protective melanin, the surrounding keratinocytes (skin cells) take it up and use it to try and shield their DNA. The more melanin that is produced, the darker the skin becomes. A tan is objective evidence that damage has already happened, and the body is expending energy to prevent such damage from happening again.
  • Sunburn occurs when your skin cannot produce melanin quickly enough to prevent UV rays from injuring the skin’s surface and the deeper blood vessels. Damage to blood vessels causes inflammation and swelling (which turns the skin red) as well as pain. Severe sunburns can cause enough inflammation that people become nauseated and sick. It can take up to 48 hours to see the full effect of sunburn.


How Much UV Reaches My Skin?

Your level of exposure to UV radiation depends upon the following factors:


How Much UV Radiation?

Did You Know?

Time of day Greatest when the sun is highest in the sky at midday, between 10 am and 4 pm. How much UV exposure you’re getting can be measured by your shadow. If it’s shorter than you, then your exposure is high; if it’s taller, your exposure is lower.
Season Greatest in late spring and early summer: from May to August in the Northern hemisphere and from November to February in the Southern hemisphere.
Altitude Greater at higher elevations like in the mountains, where the air and cloud cover is thinner. UV levels increase with altitude at the rate of 2% for every 1000-foot rise in elevation, or 1 UV index number for every 4000 feet in summer.*
Geography Strongest at the equator and in the tropics, where the sun is highest in the sky. Weakens as you move towards the earth’s poles (both north and south).
Cloud cover Strongest on cloudless days. Up to 80% of UV rays can penetrate light clouds, haze, and fog.
Reflecting surface The whiter the surface, the higher the UV level. Snow reflects the sun like a mirror. Light clothing is more reflective than dark clothing. Fresh snow reflects up to 85% of the sun’s rays, nearly doubling your exposure. Sand and concrete reflect up to 12% Grass and water reflect up to 5%.
Ozone holes Breaks in the protective ozone layer of the atmosphere significantly increase exposure to UV. Holes exist over extremely cold areas, especially over the South Pole and the Arctic.
Length of exposure The longer you are out in the sun or on a tanning device, the more UV radiation you receive. This includes any time spent outdoors, including walking, getting the mail, waiting for a train or bus, or playing an outdoor sport.

*According to the National Weather Service


Dangers of Indoor Tanning

Several studies have shown that the use of tanning devices is associated with an increased risk of developing melanoma and nonmelanoma skin cancer, including squamous cell carcinoma and basal cell carcinoma. The use of tanning devices is also associated with malignant melanoma of the eye, premature skin aging, and the development of cataracts.

How Artificial Tanning Devices Work

In the same way that the sun emits ultraviolet (UV) radiation, artificial tanning devices such as tanning beds and sunlamps also emit UV radiation.

One misconception promoted by the indoor tanning industry is that tanning devices give off only the “safe, tanning rays,” of UV radiation. However, there is no such thing as safe UV radiation. Remember, your skin produces a tan when it has been damaged by ultraviolet light. The skin does not care what the source is, or whether someone labels it as “safe.” If your skin has tanned, it is because damage has already occurred, and the skin is doing its best to prevent it from happening again.

In fact, exposure to highly concentrated UV rays of tanning devices may be even more dangerous than exposure to the sun. Tanning devices may emit UV radiation up to 15 times the strength of the midday summer sun. 12  The only difference is that the specific type and quantity of UV radiation produced from an artificial tanning device can be controlled.

Who Tans and How Often?

  • Approximately 7.8 million adult women and 1.9 million adult men in the United States tan indoors. 3
  • Thirty-five percent of American adults, 59 percent of college students, and 17 percent of teens have reported using a tanning device in their lifetime. 4
  • Nearly 70 percent of tanning salon customers are Caucasian girls and women, primarily between the ages of 15 to 29. 5,6
  • Teens are not just using indoor tanning devices for proms and homecoming; a 2015 national survey of high school students concluded that 7.3% used indoor tanning devices at least once in the past year. The prevalence of indoor tanning device use was higher among females at 10.6% than male students which was 4.0%. 7
  • Research indicates that more than half of indoor tanners (52.5 percent) start tanning before the of age 21. Forty-four point five percent of those who started tanning before age 16 reported they did so with a family member. Forty-nine point two percent of those who started tanning with a family member did so with their mother. 8

Dangers of Indoor Tanning: A Fact Sheet

Phototherapy Devices

The only time an artificial tanning device should be used is in the medical procedure of phototherapy. This process of exposing the body to UV radiation may be useful in the treatment of a number of skin conditions, including psoriasis and dermatitis. These treatments should only be conducted under medical supervision.

Regulations Governing the Use of Tanning Devices

In the United States, only 15 states and the District of Columbia completely ban the use of tanning devices for those under the age of 18. Two states allow minors to use tanning devices with a doctor’s prescription. Many states have some form of restrictions for minors which range from a parental permission to a partial ban, or combination thereof.

Brazil, New South Wales, and Australia have passed complete bans on indoor tanning.  France, Spain, Portugal, Germany, Austria, Belgium, the United Kingdom, Iceland, Italy, Finland, Norway and parts of Canada prohibit indoor tanning for youth under age 18.



What Is Sunscreen SPF?

SPF is the abbreviation for Sun Protection Factor and is the system used worldwide to determine how much protection a sunscreen provides, if it is applied to the skin at a thickness of 2 mg/cm2. This system calculates how much UV radiation (mostly UVB) it takes to cause a barely detectable sunburn on a given person with and without sunscreen applied. For example, if it takes 10 minutes to burn without a sunscreen and 100 minutes to burn with a sunscreen, then the SPF of that sunscreen is 10 (100/10).

Currently there is no internationally agreed-upon test for measuring UVA protection in human skin. An estimate is made by a laboratory test in which the proportion of radiation passing through a measured amount of sunscreen is determined. To ensure some protection against UVA, products with physical blocking agents making up some of the active ingredients are recommended.

Two Classes of Sunscreen

Sunscreens can be broadly classified into 2 groups: physical blockers and chemical absorbers.

Physical Blockers

Physical blockers are effective at protecting against both UVA and UVB radiation. They work by reflecting or scattering UV radiation.  The two most common physical blockers are titanium dioxide and zinc oxide.

Chemical Absorbers

Chemical absorbing sunscreens often contain a combination of ingredients to allow coverage against both UVB and UVA radiation. Some are also combined with physical blockers. Some organic formulations may degrade when exposed to sunlight; they may therefore not perform as well as expected.

Chemical absorbers work by absorbing ultraviolet (UV) radiation and can be further differentiated by the type of radiation they absorb, UVA or UVB, or both UVA and UVB.

The table below is a list of some of the common chemical absorbers available and the protection they provide against the UV range.