Sunscreens: How to Read a Label, Expert Tips, etc.

Sunscreens and Sunless Tanners


How do sunscreens work?

Sunscreens are topically applied products that protect the skin from the sun’s damaging ultraviolet (UV) radiation. Sunscreens work by including active ingredients that remain on the surface of the skin that absorb, scatter, or reflect the UV radiation before it reaches the skin. By filtering out harmful UV rays, sunscreens help to reduce the risk of skin cancer and premature skin aging, as well as help prevent sunburn.

According to the U.S. Food and Drug Administration (FDA), only products labeled with “Broad Spectrum” and SPF 15 or (higher) have been shown, if used as directed with other sun protection mea­sures, to provide these benefits. By contrast, any sunscreen not labeled as “Broad Spectrum” or that has an SPF value between 2 and 14, has only been shown to help prevent sunburn.

While there are many different forms (lotion, spray, etc.) and types (water resistant, fragrance free, oil free, etc.) of sunscreen available, finding one that is best suited for individual needs and proper use are key factors to protecting skin.

How are sunscreens regulated?

Sunscreens are regulated by the FDA as Over-The-Counter (OTC) drugs. As such, they must be shown to be both safe and effective and must comply with all other requirements listed in the FDA’s OTC sunscreen monograph.  Individual sunscreen active ingredients are reviewed by FDA and only those that are on FDA’s monograph approved list may be used in sunscreen products marketed in the U.S.

How are sunscreens labeled and tested?

Sunscreen effectiveness depends on a number of factors, including the Sun Protection Factor (SPF) value, if the product provides broad spectrum protection, level of water resistance, and whether the product is used as directed.

The FDA’s final rule establishing sunscreen effectiveness testing and labeling requirements was published in 2011.  These requirements outline how currently marketed sunscreen products are to be appropriately labeled and tested for both UVA and UVB protection. In addition, the directions for use in the Drug Facts help ensure the proper use of sunscreens and greater consumer protection from the damaging effects of UV radiation.

You may have seen recent media coverage of reports claiming that the SPF numbers on sunscreen products aren’t always a reliable measure of how much protection you’ll get.  All sunscreens in the United States must be tested for SPF performance using the same FDA designated clinical tests. Testing methods used to develop sunscreen shopping guides (e.g. Consumer Reports, the Environmental Working Group) are not consistent with those used by FDA, and therefore are not accurate indicators of a sunscreens’ SPF designation. Consequently, these results cannot be directly compared to a label claim.

Consumers would be wise to ignore these alarmist reports and, instead, rely upon the SPF values reported on sunscreen products.  They can rest assured that these values are based upon reliable and credible testing methods that ensure that sunscreens are safe and effective in protecting them from harmful UVA and UVB rays. FDA’s sunscreen testing requirements are well recognized by experts and regulatory authorities in the U.S. and globally.

No matter what the active ingredients, all FDA-approved sunscreen ingredients work by scattering, reflecting or absorbing UV rays.  There is no difference in efficacy between sunscreens with organic or inorganic actives, they all must be formulated to achieve their SPF label claim.

Reading the Label:

Source: FDA

What is SPF?

The Sun Protection Factor (SPF) of a sunscreen is a clinical test measure of the effectiveness of a sunscreen product against sunburn; the higher the SPF, the more sunburn protection a sunscreen offers. The SPF indicates how long a person can be exposed to UV radiation before getting sunburn with a sunscreen applied compared to how long they can be exposed before getting a sunburn without sunscreen. For example, someone who would burn after 10 minutes in the sun without a sunscreen would expect to burn after 5 hours (300 min) if protected by a sunscreen with SPF 30.

What does Broad Spectrum mean?

UV radiation in sunlight is divided into several ranges depending on the wavelength. UVB radiation covers the wavelength range between 290 and 320 nanometers, and UVA radiation covers the wavelength range between 320 and 400 nanometers. Sunburn is primarily caused by UVB. Both UVB and UVA can cause sunburn, skin cancer, and premature skin aging.

A sunscreen can be labeled “Broad Spectrum” if it provides UV protection across both the UVB and UVA wavelength ranges. The US Broad Spectrum Test is an in vitro (laboratory) test that measures a sunscreen product’s transmittance/absorbance of ultraviolet (UV) radiation across both the UVB and UVA regions of the spectrum.  The test is referred to as the ‘critical wavelength’ test. For a sunscreen product to pass the test, it must be demonstrated that it has a critical wavelength of at least 370 nanometers [nm] or greater). FDA set the critical wavelength at 370nm because that wavelength “is sufficiently difficult to achieve and will ensure that sunscreen products meeting this threshold provide a significant amount of broad spectrum protection.”

How effective is my sunscreen?

Sunscreen effectiveness depends on a number of factors, including the Sun Protection Factor (SPF) value, if the product provides broad spectrum protection, level of water resistance, and whether the product is used as directed. The amount of protection derived from a particular sunscreen also depends on factors such as:

  • The skin type of the user – Whatever our skin color, all are potentially susceptible to sunburn and other harmful effects of expo­sure to UV radiation. While we all need to take precautions to protect our skin, people who need to be especially careful in the sun include those who have pale skin; blond, red or light brown hair; and those who have been treated for skin cancer.
  • The amount applied and frequency of re-application – FDA recommends that you apply sunscreen 15 minutes before going out in the sun and reapply it every 2 hours – more often if you’re sweat­ing or jumping in and out of the water.  Sunscreen should be applied evenly on all parts of your body that will be in the sun. It takes at least one ounce of sunscreen lotion, the size of a golf ball, to cover your entire body.
  • The water-resistance of the product – FDA’s regulations now require that if a product’s front label makes claims of being water resistant, it must designate whether it’s protective for 40 or for 80 minutes while swimming or sweating.  Additionally, manufacturers may no longer make claims that their sunscreens are “waterproof” or “sweatproof.”

Simple tips for sun safety from the American Cancer Society (ACS) include:

  • Do not use tanning booths, beds or lamps.  These devices do not provide a ‘safer way’ to tan.
  • When outdoors, stay in the shade whenever possible – particularly between the hours of 10:00 am – 4:00 p.m. when the sun’s rays are most intense.
  • Wear sun protective clothing such as a long-sleeved shirt, a wide-brimmed hat and UV protective sunglasses.
  • Use a broad spectrum sunscreen with an SPF of 30 or higher on all skin that is not covered every day, even on a cloudy day.
  • Reapply sunscreen every two hours or immediately after swimming or sweating.
  • Visit your healthcare professional every year for a skin exam.

Learn more about FDA regulation of OTC Sunscreen products:


American Academy of Dermatology: Sunscreen Resource Center

Skin Cancer Foundation: Prevention Guidelines

American Cancer Society Infographic: Don’t Fry Preventing Skin Cancer

American Cancer Society Fact Sheet: UV Radiation and Cancer

Marie Claire: 4 Myths About Sunscreen That You Definitely Believe Are True

Common Ingredients

See Also