October 2021 • Vol. 27 • Issue 8
The Numerous Contributions by Dr. Kerry Hanson to our Current Knowledge of Sunscreen Protection
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…by Paul Thau
uring the late 1990s, when I was a member of L’Oréal’s technology surveillance group, I was asked to get in contact with Kerry Hanson Ph.D., who was conducting advanced research studies at the University of California, San Diego on urocanic acid, which is a natural ingredient found in skin. I was successful in reaching her and she provided the L’Oréal sunscreen team with updated information on her research studies with urocanic acid. Located in the stratum corneum, urocanic acid is a major epidermal chromophore for UV radiation. This simple molecule has attracted a great deal of research interest over the past half century, initially as a putative "natural sunscreen" and later as a mediator of photo-immunosuppression with a consequent role in photo-carcinogenesis. Urocanic acid was present in a number of commercial sunscreens in the late 1990s; however, Kerry Hanson’s studies indicated that there were safety concerns for its continued use in sunscreens formulations. This finding was later corroborated by future studies that she conducted in the early 2000s. Since I was overly impressed with Kerry Hanson’s skills and accomplishments, I recommended her to Bram Shroot, Ph.D., who was in charge of Galderma’s R&D laboratories located in San Diego at that time. She had an internship at the facility in La Jolla, California and received an award for her accomplishments after working there for less than one year. Kerry Hanson joined the chemistry department at the University of California, Riverside in the early 2000s and I remained in contact with her. I recommended her to several of my colleagues and clients in the industry because of her special talents for screening the efficacy of new sunscreen formulations. I also recommended her as a speaker at future scientific meetings. At the SCC Annual meeting in 2003, Kerry presented her work which eventually was published as an article in the Journal of Cosmetic Science on the topic of “Bioconvertible vitamin antioxidants improve sunscreen photoprotection against UV-induced reactive oxygen species (ROS)”.1 To the best of my knowledge, she won the best paper award that year. From 2000 to 2014, I served as a consultant for several firms and recommended Kerry for her specialized talents in testing new sunscreen formulations. A study by her that really stands out in my mind is where she used two-photon fluorescence imaging to test the efficacy of sunscreens containing the antioxidants, vitamin E and diethylhexyl syringylidene malonate, to prevent UV-induced ROS in the lower stratum corneum. The addition of the antioxidants was found to significantly improve the ability of low and high SPF sunscreens to attenuate ROS formation in UV-exposed skin.2 (continued on Page 6)
I N T U I T I V E N AT U R E : C O L O R A N D B E A U T Y T R E N D S • O C T O B E R 2 8 T H ...see pages 8 for more information.