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Chemical Sunscreens

 
The below information is part of Beauty Care Choices ongoing commitment to providing our customers with the latest in product and ingredient information. Please note: the FDA and Beauty Care Choices are NOT advocating to discontinue the use of sunscreens. They are essential. Melanoma (Skin cancer) incidence rates continue to rise, making risk from excess sun exposure an important public health priority. Yet despite what we know about prevention, skin cancer remains the most commonly diagnosed cancer in the United States. Used with other sun protective measures, broad spectrum sunscreens with SPF values of at least 15 are critical elements for preventing skin cancer and protecting the skin from sunburn and other UV damage.

As published in the May 6, 2019, Journal of the American Medical Association, Matta et al,P(2) describe the results of an exploratory maximal usage trial (MUsT) evaluating the systemic absorption (through the skin and into the body) of sunscreen active ingredients using four commercially available sunscreen products applied under maximal use conditions. Objective to determine whether the active ingredients (avobenzone, oxybenzone, octocrylene, and ecamsule) of 4 commercially available sunscreens are absorbed into systemic circulation.

A MUsT study evaluates the systemic absorption of a topical drug (i.e., one applied to the skin) when used according to the maximum limits of the product's directions for use. Because sunscreens are formulated to work on the surface of the skin, some have argued that sunscreens would not be absorbed in appreciable quantities and therefore that MUsT studies are unnecessary. In this pilot study, all four active ingredients tested were absorbed from each formulation tested, showing that absorption of sunscreens is not just a theoretical concern.

The sunscreens tested were all chemical. As a reminder, there are two types of sun blockers:

  • Physical - these sunscreens contain extremely fine particles of minerals that stay on the skin's surface and create a barrier to reflect the sun's rays. They have a tendency the last a little longer on the skin. Look for the active ingredients Titanium Dioxide and Zinc Oxide.
  • Chemical sunscreens are made of synthetic compounds that absorb ultraviolent radiation. They are good for drier skin types and offer more coverage against both UVA and UVB rays. You need to wait at least 20 minutes after applying to receive adequate sun protection.

    The FDA's proposed rule is asking for additional safety data on 12 active sunscreen ingredients. FDA expects that sunscreen active ingredients that are absorbed into the bloodstream at a level of 0.5 ng/mL (nanograms per milliliter) or higher, or that have potential safety concerns, would generally need to undergo further testing to help determine if they increase the risk for cancer, birth defects, or other adverse effects. All of the active ingredients in the study noted above were absorbed in levels substantially higher than the 0.5 ng/mL threshold value cited in the proposed rule. However, without further testing, FDA does not know what levels of absorption can be considered safe.

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