How Much of Your Sunscreen is Absorbed? Interview with:

David Strauss, MD, PhDDirector, Division of Applied Regulatory ScienceU.S. Food and Drug AdministrationCenter for Drug Evaluation and Research

Dr. Strauss

David Strauss, MD, PhD
Director, Division of Applied Regulatory Science
U.S. Food and Drug Administration
Center for Drug Evaluation and Research What is the background for this study? What are the main findings?

Response: It is unknown whether most active ingredients in sunscreens are absorbed. 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.

This randomized clinical trial demonstrated systemic exposure of 4 commonly used sunscreen active ingredients on application of sunscreen products under maximal use conditions consistent with current sunscreen labeling.

All 4 sunscreen active ingredients tested resulted in exposures exceeding 0.5 ng/mL.  Continue reading

Hot Sun Increases Absorption of Sunscreen Ingredients Interview with:
Audra Stinchcomb, PhD

Principal Investigator
Professor of Pharmaceutical Sciences
University of Maryland School of Pharmacy What is the background for this study?  

Response: We have been studying the heat effects and repeated dose effects on the absorption of drugs across the skin for more than 5 years.  We were curious to see if the effects we saw on gel, cream, and ointment pharmaceuticals also occurred with sunscreen.

Sunscreens are typically used in the hot sun and with reapplication every 80 minutes or so, depending on the product and user.

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South Pacific Island Nation First Country to Ban Environmentally Harmful Sunscreens Interview with:
"Protect Coral Reefs" by NOAA's National Ocean Service is licensed under CC BY 2.0Ariel Kushmaro and Esti Kramarsky-Winter
Department of Biotechnology Engineering, Ben Gurion University
Beer Sheva, Israel

The Republic of Palau, a South Pacific island nation, became the world’s first country to ban sunscreen products containing environmentally harmful ingredients What is the background for this announcement? What are the main findings? 

Response: Coral reefs are important ecosystems that are under threat due to global human driven climate change. In addition to global changes, local hazards such as point pollution by eutrophication, dredging and chemical pollution are exacerbating and promoting reef destruction at local levels. This destruction affects not only island nations that depend on these reefs for protection and livelihood, they affect humanity as a whole as they are an important source for food and novel drugs and new materials.

Our recent studies have shown that chemicals found in most commercial sunscreens and creams used to protect humans from deleterious effects of UV A and UVB wash off into the environment are persistent, have endocrine disruptive effects, and thus deleteriously affect marine organisms including corals.  Continue reading

Shining Sunlight on Sunscreens and Sunburns Interview with:
Dr. Janet Prystowsky, MD

Dr. Janet Prystowsky, MD Dr. Prystowsky is a leading board-certified dermatologist in New York City.  In addition to her private practice, Dr. Prystowsky is a senior attending physician at Mount Sinai Roosevelt/St. Luke’s Medical Center.

Dr. Prystowsky

Dr. Prystowsky is a leading board-certified dermatologist in
New York City.  

In addition to her private practice, Dr. Prystowsky is a senior attending physician at Mount Sinai Roosevelt/St. Luke’s Medical Center. Are all sunscreens created equally? 

Response: Not all sunscreens are created equally. Always choose a broad-spectrum sunscreen that is water resistant if you are planning outdoor sports (with sweating) or swimming. Water resistance is a must when you are swimming or sweating (and who isn’t sweating on a hot summer day?)

However, you do not need water resistance if you are walking a few blocks in moderate temperatures. In that situation, a moisturizer sunscreen that is not water resistant is OK and may feel more comfortable on your skin.

As far as ingredients go, your best choice is a mineral based sunscreen with zinc oxide and/or titanium dioxide.

Sunscreens that are not broad spectrum may protect you from sunburns but will not protect you from photodamage that can lead to premature aging and skin cancer.

Mineral based sunscreens are preferable over chemical sunscreens because the long-term effects of chemical sunscreens aren’t well understood. What we do know is that chemical sunscreens can absorb into our bloodstream and potentially have hormonally disruptive effects.  Continue reading

Current Sunscreens Lack Protection Against Damaging Effects of Visible Light Interview with:
Prof. Dr. Mauricio S. Baptista
Chemistry Institute (IQ-USP)
University of São Paulo

“Tanning in the sun” by S B is licensed under CC BY What is the background for this study? What are the main findings?

Response: This research started around 7 years ago. Our lab had a lot of previous experience in studying how photosensitizers (molecules that absorb light and transfer energy to others in its surroundings) used for Photodynamic Therapy, behave in the intracellular environments. We realized that most scientific work that defined the effects of sun in skin did not really consider looking into the properties of the molecules that are naturally found in skin and that absorb light. We also realized that very likely natural photosensitizers present in the skin behaves similarly when excited by either UVA or visible light. It all depends on which molecule absorb light and how the subsequent excited states behave. The work started by looking at melanin and melanocyte cells (Chiarelli-Neto et al Free Radic Biol Med 2011, 51, 1195; Chiarelli-Neto O et al. PLoS ONE, 2014  9(11): e113266). More recently we start looking at keratinocytes  and liposfucin (Tonolli et al Journal of Investigative Dermatology 2017, 137, 2447).

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New Cream May Lead To Non Sun-Induced Tanning Interview with:

David E. Fisher MD, PhD</strong> Edward Wigglesworth Professor & Chairman Dept of Dermatology Director, Melanoma Program MGH Cancer Center Director, Cutaneous Biology Research Center Massachusetts General Hospital Harvard Medical School Boston, MA 02114

Dr. Fisher

David E. Fisher MD, PhD
Edward Wigglesworth Professor & Chairman
Dept of Dermatology
Director, Melanoma Program MGH Cancer Center
Director, Cutaneous Biology Research Center
Massachusetts General Hospital
Harvard Medical School
Boston, MA 02114 What is the background for this study? What are the main findings?

Response: This study grew from an interest to mimic the dark pigmentation patterns in human skin which are known from epidemiology to be associated with low skin cancer risk. In the current work, a molecular inhibitor of the SIK enzyme was used to block the inhibitory action of SIK relative to melanin synthesis. The result was stimulation of dark pigmentation within human skin.

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New Compounds May Extend Efficiency of Sunscreens Interview with: Dr. Diego Sampedro PhD

Dr. Diego Sampedro Interview with:
Dr. Diego Sampedro PhD
Department of Chemistry, Centro de Investigación en Síntesis Química (CISQ)
Universidad de La Rioja
Logroño, Spain What is the background for this study?

Response: Skin cancer is currently the most common type of cancer. While it implies a relatively low mortality rate, the reported cases of all types of skin cancer have been steadily increasing for the last decades. The ozone layer depletion and longer sunlight exposure times due to outdoors activities contribute to this increase. Solar light is well-known to lead to several skin cellular problems, including DNA damage, mutations, oxidative stress, sunburn and immune suppression. These deleterious effects of sunlight may be mitigated by the use of sunscreens.

Sunscreens are inorganic or organic substances that are directly applied onto the skin, designed to minimize light transmission into the skin, mainly in the ultraviolet region of the solar spectrum. However, serious concerns exist about the safety of several commercial sunscreens components, as well as several drawbacks due to the lack of stability, biodegradability and effectiveness for skin protection. Thus, the development of new (and more efficient) types of sunscreens is of critical importance with a great potential impact in public health and industrial applications.

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99% of Dermatologists Recommend Sunscreen Use to Their Family and Friends Interview with:
Aaron S. Farberg, MD

Department of Dermatology
Icahn School of Medicine at Mount Sinai What is the background for this study? What are the main findings?

Response: Regular sunscreen use is a critical component of sun protection and has been shown to reduce skin cancer risk. However, there have often been conflicting sunscreen messages (sometimes without scientific support) that have led to confusion by the public. Controversy has also emerged surrounding the safety and possibility of adverse effects from various sunscreen ingredients. The purpose of this study was to determine US dermatologists’ actual sunscreen perceptions, potential safety concerns as well as their recommendations and personal usage. Some people are so affected by the sun that they require a brand of Custom Sunscreens to help protect them from the sun.

Our study found that dermatologists have an overall positive view of sunscreen. 97% of dermatologists agree that regular sunscreen use helps lower skin cancer risk, 100% agree that it reduces subsequent photoaging, and 99% recommend their family/friends use sunscreen. Nearly all (96%) consider FDA approved sunscreens currently available in the US to be safe and (99%) believe their patients generally under-apply sunscreen.

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Chemical Sunscreens May Reduce Male Fertility Interview with:
Anders Rehfeld MD, PhD Student
Faculty of Health and Medical Sciences
Department of Cellular and Molecular Medicine
University of Copenhagen
Copenhagen Denmark What is the background for this study? What are the main findings?

Response: Human fertility is declining in many areas of the world and the reason is largely unknown. Our study shows that 44% of the tested chemical UV filters can induce calcium signals in human sperm cells, thereby mimicking the effect of progesterone. Progesterone-induced calcium signals, and the sperm functions it triggers, is absolutely essential for the human sperm cell to normally fertilise the human egg.

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Biopolymers from Algae May Provide Broad Spectrum Photoprotection

Susana C. M. Fernandes, PhD
Researcher (Individual Marie Curie Fellowship – IEF) and
Professor Vincent Bulone
Division of Glycoscience, School of Biotechnology
Royal Institute of Technology (KTH), Stockholm, Sweden and
ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite campus, Urrbrae, South Australia Australia

MedicalResearch: What is the background for this study? What are the main findings?

Response: We have exploited unique properties of natural compounds to develop novel materials that are capable of absorbing both UV-A and UV-B radiations. The active UV-absorbing molecules are known as mycosporines and mycosporines like-amino acids and they occur in different organisms such as algae, photosynthetic bacteria (cyanobacteria) and some fish species that thrive in, e.g., the tropical waters of the Great Barrier Reef. These compounds were combined with a carbohydrate polymer found in the shells of crustaceans, the exoskeleton of insects and the cell walls of fungi. Chitosan provided a matrix on which mycosporines were attached using a simple chemical method already used for other purposes in, e.g., the pharmaceutical industry. Chitosan can typically be extracted from food waste such as the shells of shrimps. The immobilization of mycosporines on chitosan allowed the development of unique materials that have many potential applications relevant to a wide range of sectors, including cosmetics, sunscreen creams, wound dressings, plasticizers in paints and varnishes, coatings of outdoor furniture and other materials such as fabrics for shades, textiles, car dashboards, etc. In addition to being highly efficient for protection against UV-A and UV-B, the materials were shown to be photostable, thermoresistant and biocompatible. Compared to existing sunblock formulations, the materials have no detrimental effects on health and the environment. They are also fully recyclable.

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Chinese Licorice May Enhance Skin Protection From Sun Exposure interview with:
J. Kühnl, D. Roggenkamp, G. Neufang
Research & Development, Beiersdorf AG, Hamburg

MedicalResearch:What is the background for this study? What are the main findings?

Response: The skin is constantly challenged by environmental stressors that induce inflammatory processes, resulting in skin damage and –in the long term- consequently aging processes. UV-irradiation is an important exogeneous stressor. Even the best filter systems do not completely abolish the impact of UV radiation. For example, after application of a SPF50+ sun lotion, about 2% of UV-rays still reach the skin. However, the skin developed strategies to cope with exogenous stressors: Intracellular thiols quench harmful UV-derived free radicals and a multitude of detoxifying enzymes convert noxious compounds and metabolites into harmless species.

We strived to specifically stimulate these cytoprotective cellular systems in order to tip the balance in favor of more robust skin cells.

Previous studies showed that the root extract of the plant Glycyrrhiza inflata (Chinese Licorice) exhibits anti-inflammatory and anti-microbial effects. The major phenolic constituent of the licorice extract is Licochalcone A (LicA) and this compound is largely responsible for the beneficial effects. This was explained by LicA´s inhibitory effect on the pro-inflammatory transcription factor NFkB and its antioxidant properties.

However, in this study, we could add another facet of LicA´s efficacy: by activating the transcription factor Nrf2, LicA stimulates the expression of cytoprotective enzymes such as heme oxygenase I and the key enzyme of glutathione synthesis, resulting in increased intracellular thiols concentrations. Consequently, when pre-incubated with LicA, isolated human skin cells were more robust against solar simulated light-induced cellular damage, indicated by a significantly decrease in the generation of free radicals in vitro. In a translational approach, we conducted a study with healthy volunteers demonstrating that the application of a lotion containing LicA-rich root extract on the inner forearms for two weeks protected the skin from UV-provoked oxidative stress.

Thus the cellular effects of licorice are able to provide a protective shield from sun exposure, supporting and going beyond the action of sunscreens regarding sun protection. Continue reading