About the Authors Daniel B. Yarosh, PhD, Independent Technology Advisor Daniel B. Yarosh, PhD., is an independent advisor in cosmetics, beauty, dermatology, pharmaceuticals, biotechnology, and neuromar- keting. He was the ch ief technology a dvisor and senior vice presi- dent, Bas ic Science Research, Estee Lauder Co., and was responsible for the company’s worldwide basic research. Dr. Yarosh also served on the Board of Directors of Aceto Corp., a specialty chemical and generic drug company headquartered in Port Washington, NY. Dr. Yarosh received his BA degree in biology from Macalester College, St. Paul, Minnesota, in 1976, and his doctorate in molecular biology from the University of Arizona College of Medicine in 1978. He se rved as a National Science Foundation fellow at Brookhaven National Laboratory, Upton, New York, and then a staff fellow and cancer expert at the National Cancer Institute of the National Institutes of Health, Bethesda, Maryland. In 1985, Dr. Yarosh founded the biotechnol- ogy company AGI Dermatics, with an emphasis on the commercial application of DNA repair. He is the inventor of Dimericine® (T4N5 liposome lotion), which is a liposomal DNA repair enzyme for the prevention of skin cancer. AGI Dermatics also supplied ingredients to many major world- wide cosmetic and personal care companies. In 2006, the company launched its own Remergent® brand of skincare products, including sunscreens and prescription drugs. In 2008, AGI Dermatics was acquired by Estee Lauder Co. Dr. Yarosh is the author of more than 140 scientifi c articles and two dozen patents. He has been an active participant in the dermatology and New York biotechnology communities. In 2004, the Inter- national Union of Photobiology presented Dr. Yarosh with the Finsen Award, which is granted every 4 years at the International Congress for Photobiology for breakthrough research in the photobiology sciences. He was honored by the American Cancer Society, Nassau County, for his professional service in 2008. His book The New Science of Perfect Skin, about skincare technology in the cosmetic market- place, was published by Random House in May 2008. Dr. Yarosh researches and writes about the evolutionary biology of beauty and neuromarketing on his website www.danyarosh.com. Angela Tewari, NHS Dermatology Consultant Angela Tewari is an NHS dermatology consultant at the prestigious King’s College Hospital in London seeing a wide breath of complex clinical adult and pediatric dermatology and performing skin surgery. Angela completed her dermatology training in London, presenting her clinical work at a number of national and international meetings, and won a number of prizes. Before this, she was awarded a competitive Medical Research Council (MRC)/British Association of Dermatology (BAD)/British Skin Foundation (BSF) fellowship to complete a PhD looking at the effects of UVA1 in sunshine and how it causes cellular and molecular damage in the skin. In particular, she examined for the presence of DNA damage markers—cyclobutane pyramidine dimers (CPDs)— and showed that they are produced after UVA1 albeit much less than UVB and have a predilection for the basal epidermis. She has published her work in a number of high-impact journals including the Journal of Investigative Dermatology, and she has a small BSF grant to pursue further research into the effects of ultraviolet radiation on the skin.

J. Cosmet. Sci., 71, 209–214 (July/August 2020) 209 Importance of DNA Repair: Recent Advances DANIEL B. YAROSH and ANGELA TEWARI , Daniel B. Yarosh, Inc., Merrick, NY (D.B.Y.), Department of Dermatology, Kings College Hospital, NHS Foundation Trust, London SEI 9RT, United Kingdom (A.T.) Synopsis Our defense against solar ultraviolet (UV) damage to skin comprises endogenous mechanisms of DNA repair and pigmentation, and exogenous application of light-absorbing and refl ecting sunscreens. Our most important endogenous defense, DNA repair, has been the focus of molecular and clinical research, and recent advances are summarized here. The approach of using microbial DNA repair enzymes to augment the natural DNA repair capacity of skin has gained acceptance in many commercial products, and clinical studies have supported their benefi ts. INTRODUCTION DNA repair is the most important endogenous protection against sunlight damage to skin. A defi ciency in DNA repair causes the genetic disease xeroderma pigmentosum (XP) classic form, wherein one of seven genes is disabled by mutation, resulting in extreme sun sensitivity, skin cancer, and premature death (1). The symptoms of XP are as severe in people of color as in light-skinned patients, demonstrating that effi cient DNA repair capacity is more important in providing protection from ultraviolet (UV)-induced pre- cancerous cutaneous changes than is melanin pigmentation (1). Even the heavy melanin content of black skin affords a protection of only 20- to 60-fold against skin cancer (2), whereas XP patients younger than 20 years have a 10,000-fold increased risk of non- melanoma skin cancer and a 2,000-fold increased risk of melanoma (1). Chemical and physical sunscreens are the most important exogenous systems of photo- protection. Despite their intrinsic ability to block DNA damage (3), sunscreens are often used at a fraction of the recommended application dose (4). The potential for systemic absorption and environmental damage (5) has led to a search for alternatives, and increas- ing the endogenous DNA repair system is an attractive goal. Here, we will highlight recent advances in understanding DNA repair protection against solar radiation and review the support for the use of exogenous DNA repair enzymes for photoprotection. Address all correspondence to Daniel B. Yarosh at dyarosh@danyarosh.com.