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

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 the harmful UV radiation, sunscreens help to reduce the risk of skin cancer and early skin aging, as well as help prevent sunburn. However, only products labeled with “Broad Spectrum” and SPF 15 or higher (see more details below) have been shown, if used as directed with other sun protection mea­sures, to provide these benefits.[1] 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 works for an individual and proper use are key factors to protecting skin.  

[1] According to FDA, Sunscreens with a Sun Protection Factor (SPF) of at least 15 and with Broad Spectrum provide protection against skin aging and skin cancer.


Reading the Label:

Sunscreens are regulated by the U.S. Food and Drug Administration (FDA) as Over-The-Counter (OTC) drugs. As such, they must be shown to be 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. FDA's sunscreen testing requirements are well recognized by experts and regulatory authorities in the U.S. as well as globally.

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


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 protection a sunscreen offers against the harmful effects of UV radiation. The SPF indicates the time a person can be exposed to UV radiation before getting sunburn with a sunscreen applied relative to the time they can be exposed before getting a sunburn without sunscreen. For example, someone who would burn after 12 minutes in the sun without a sunscreen would expect to burn after 2 hours (120 min) if protected by a sunscreen with SPF 10.

Broad Spectrum:

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 range. The 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 “will ensure that sunscreen products meeting this threshold provide a significant amount of broad spectrum protection.”

Varying Protection Levels:

The 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 include:

  • Avoid the sun during the peak hours of 10:00 am- 4 p.m.

  • Wear sun protective clothing, including a wide-brimmed hat and UV protective sunglasses

  • Use a broad spectrum sunscreen with an SPF of 30 or higher 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

Find out more about FDA regulation of OTC Sunscreen products:

Understanding Over-the-Counter Medicines: Sunscreen and Sun Protection

FDA Sheds Light on Sunscreens

Sun Protection Guide

FDA approved sunscreen ingredients

Other Resources

American Academy of Dermatology: Sunscreen 101: Dermatologists answer burning questions about sunscreens

Skin Cancer Foundation: Prevention Guidelines 

Common Ingredients: 
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