Sunscreens prevent skin damage by reflecting, absorbing, and/or scattering UV radiation, but what about pros and cons?

For some individuals, sunscreen products may be applied in substantial amounts multiple times every day over the course of a lifetime as both primary sunscreen products, starting from an age of 6 months, and as ingredients in cosmetic products.

Application to the skin can result in multiple grams of sunscreen being applied in a day, even with modest use.

Although OTC sunscreen products are widely used, little is known about systemic exposure for most active ingredients.

The US Food and Drug Administration (FDA) has provided guidance that sunscreen active ingredients with systemic absorption greater than 0.5 ng/mL or with safety concerns should undergo nonclinical toxicology assessment including systemic carcinogenicity and additional developmental and reproductive studies.


Understanding the extent of systemic exposure of these products is important, as even a low percentage of systemic absorption (eg, 0.1%) could represent a significant systemic exposure (eg, milligrams of ingredient being systemically absorbed per day).

The clinical relevance of systemic exposure is not well understood.

The objective of a new study was to determine whether the active ingredients (avobenzone, oxybenzone, octocrylene, and ecamsule) of 4 commercially available sunscreens are absorbed into systemic circulation.

In this preliminary study involving healthy volunteers, application of 4 commercially available sunscreens under maximal use conditions resulted in plasma concentrations that exceeded the threshold established by the FDA for potentially waiving some nonclinical toxicology studies for sunscreens.

See also
U.S. NIH study links ultraviolet filters to reduce fertility in men (2014-11-21)

Should You Put Sunscreen on Infants? (2017-08-14)

Use Sunscreen Spray? Avoid Open Flame (2013-07-05)

For more information
Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients – A Randomized Clinical Trial

FDA – the U.S. Food and Drug Administration


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