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What’s New in Photoprotection?

Dermatology TimesDermatology Times, June 2021 (Vol. 42, No. 6)
Volume 42
Issue 6

New regulations, latest absorption data, and updates on environmental and health impacts are shaping the world of photoprotection.

With summer in full swing, dermatologists are counseling patients more frequently on sun and photoprotection. And this year, they have more options to discuss, according to Henry W. Lim, MD.

Lim, a dermatologist in the department of dermatology at the Henry Ford Health System in Detroit, Michigan, spoke about new developments in photoprotection in a presentation at the American Academy of Dermatology Virtual Meeting Experience 2021 (AAD VMX) held in April.1 


In his presentation, Lim began by discussing the skin absorption of UV filters, mentioning a study published in 20202 that examined 48 healthy individuals with Fitzpatrick skin types II to IV. Study participants were instructed to apply a single application of sunscreen on day 1 and then 4 applications per day at 2-hour intervals on days 2 through 4. Participants used 2 mg/cm2 of sunscreen on 75% of their body surface area.

Investigators tested 4 sunscreen products—lotion, aerosol spray, nonaerosol spray, and pump spray—that contained the active ingredients oxybenzone, octocrylene, octisalate, octinoxate, avobenzone, and homosalate. Blood samples were collected on days 1 through 21 and stratum corneum was evaluated for UV concentration via tape stripping on days 7 and 14.

Lim noted that 0.5 ng/mL plasma level is a threshold used by the FDA for waiving safety studies.

Results of the study showed that levels greater than 0.5 ng/mL were detected after a single application on day 1 for all the active ingredients. The findings also revealed that the geometric mean for maximal plasma concentrations was greater than 0.5 ng/mL, levels of the same concentration were detected up to day 7 and up to day 21 for oxybenzone, and all active ingredients were detected in the skin on days 7 and 14.

“All UV filters were detected in the skin on day 7 and day 14 by tape stripping method, which is not surprising because when we apply sunscreen we want a UV filter to stay on the surface of the skin,” Lim said.

The results do not indicate that individuals should refrain from using sunscreen, and there is a need for further studies to help determine the clinical significance of the findings, according to the study authors.


During his presentation, Lim also provided an up-to-date walkthrough of photoprotection regulations.

An FDA proposed rule released February 26, 2019,3 suggested that of the 16 UV filters listed in the 1999 Final Monograph, 2 filters were Category I—zinc oxide and titanium dioxide, which were considered to be generally recognized as safe and effective (GRASE). Furthermore, 2 filters fell under Category II but were not considered GRASE—para-aminobenzoic acid (PABA) and trolamine salicylate. And 12 filters fell under Category III with insufficient safety data to make a positive GRASE decision.

“The rule also proposed an SPF [sun protection factor] cap at 60 plus and strengthening of broad-spectrum coverage by adding UVA1 over UVA plus UVB to a ratio of 0.7,” Lim said. “That would make sunscreen have a more potent UV protection, which I believe is good for all of us.” A final rule was scheduled for September 2020, but no such guidance has been released yet, he noted.

Lim also delved into the impact of the Coronavirus Aid, Relief, and Economic Security (CARES) Act, which was signed into law in March 2020.

Under the CARES Act, the FDA is moving away from a “laborious rulemaking process” to an administrative order process, meaning that it should take less time to implement a monograph. Therefore, there will not be a final rule.4

Also, under the provisions of the act, the FDA is required to issue a proposed administrative order by September 27, 2021. Once issued, the industry would have 1 year to have the products they offer in the United States comply with the order.

“The CARES Act also incentivizes innovation by providing for an 18-month exclusivity period for new filters to the requesting manufacturer,” Lim said. “Looking at this timeline and assuming everything runs smoothly, we will see products on the shelves in compliance with these particular guidelines around 2023.”

Environmental and Health Impacts

Lim also mentioned the environmental and health impacts associated with photoprotection. 

In a critical review highlighted in his presentation,5 investigators reviewed all of the published photoprotection studies up to June 2020, 32 total.

They identified 14 various organic UV filters found in seawater near coral reefs in the nanograms per liter range. Also, the review found 9 papers that reported toxicological findings in the micrograms per liter to milligrams per liter range. When compared with concentrations in seawater, toxic effects of UV filters were found at 1000 to 1 million-fold higher concentrations.

The review concluded that there is currently limited evidence suggesting coral reefs are adversely affected by exposure to UV filters, however, the authors noted major data gaps that should be immediately addressed with high-quality monitoring, fate, and toxicity studies.

In his presentation, Lim also mentioned the effects of photoprotection on human health. 

A study6 published in September 2020 investigated the effects of UV filters on human health. Results found that current evidence was not sufficient to support the causal relationship between the elevated systemic level of oxybenzone or octinoxate and adverse health outcomes. 

Despite these findings, on February 9, 2021, the National Academies of Sciences, Engineering, and Medicine formed a committee dedicated to studying the relationship between UV filters and environment and human health, which is sponsored by the Environmental Protection Agency, according to Lim. AAD has also advocated for the study and selected 2 members for the committee.

Currently, Lim said, Hawaii has banned oxybenzone and octinoxate as of January 2021 and the U.S. Virgin Islands has banned octocrylene. Also in January, Hawaii introduced 3 bills (HB102, SB366, and SB132) that propose the ban of sunscreens containing avobenzone and octocrylene.

How to Advise Patients

With more areas of the world considering the ban of some UV filters for health and environmental reasons, patients may be reluctant or confused when choosing a sunscreen or other form of protectant, Lim said.

He suggested physicians advise their patients to seek shade, wear protective clothing—such as sunglasses and wide-brimmed hats—and apply broad spectrum, tinted sunscreen of SPF 30 or more to exposed areas.

For patients concerned about the environmental effect of oxybenzone and octinoxate, Lim recommended using mineral sunscreen and practicing rigorous photoprotection by taking 600 to 800 IU of vitamin D daily.

“We know that adverse effects of sun exposure are well established, so the practice of photoprotection is essential,” Lim said.

 Photoprotection Recommendations

  • Seek shade
  • Wear protective clothing
  • Apply broad spectrum, tinted sunscreen SPF 30 or higher to exposed areas
  • Consume 600 to 800 IU of vitamin D daily


Lim is an investigator for Incyte, L’Oréal, Pfizer, and Patient-Centered Outcomes Research Institute in relation to photodermatology. He also reports working as a consultant with Pierre Fabre, Isdin, Ferndale, La Roche-Posay, and Beiersdorf; and as an educational speaker for La Roche-Posay and Cantabria Labs.


  1. Lim HW. New developments in photoprotection. Presented at: American Academy of Dermatology Virtual Meeting Experience 2021; April 23-25, 2021; virtual.
  2. Matta MK, Florian J, Zusterzeel R, et al. Effect of sunscreen application on plasma concentration of sunscreen active ingredients: a randomized clinical Trial. JAMA. 2020;323(3):256-267. doi:10.1001/jama.2019.20747
  3. Wang SQ, Lim HW. Highlights and implications of the 2019 proposed rule on sunscreens by the US Food and Drug Administration. J Am Acad Dermatol. 2019;81(2):650-651. doi:10.1016/j.jaad.2019.04.007
  4. Mohammad TF, Lim HW. The important role of dermatologists in public education on sunscreens. JAMA Dermatol. Published online March 24, 2021. doi:10.1001/jamadermatol.2020.5393
  5. Mitchelmore CL, Burns EE, Conway A, Heyes A, Davies IA. A critical review of organic ultraviolet filter exposure, hazard, and risk to corals. Environ Toxicol Chem. 2021;40(4):967-988. doi:10.1002/etc.4948
  6. Suh S, Pham C, Smith J, Mesinkovska NA. The banned sunscreen ingredients and their impact on human health: a systematic review. Int J Dermatol. 2020;59(9):1033-1042. doi:10.1111/ijd.14824
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