URGENTLY REQUIRED: A WARNING LABEL ON SUNSCREENS WITH BIOAVAILABLE UV FILTERS
Basic physiology and scientific studies have confirmed over 3 decades that SOLUBLE petrochemical organic (carbon based) UV filters are all absorbed through human and wildlife skin. They become bioavailable and bioactive reaching every cell, neuron, and hormone receptor in the human body - causing hormone disruption, DNA mutations, and epigenetic changes.
1990 - I detected two sunscreen filters - avobenzone and oxybenzone - in fetal blood samples at 32-36 weeks.
1997 – Oxybenzone detected in breast milk, and Hayden et al warned about the potential risks of systemic absorption of sunscreens after topical application (Lancet 1997). In 2001 Bos & Meinardi provided the irrefutable explanation - “The 500 Dalton rule for the skin penetration of chemical compounds and drugs”. Any chemical with a molecular weight (MW) below 500 Daltons (g/mol) penetrates human epidermis to reach blood and all tissues – albeit at different rates to attain varying peak levels. All soluble petrochemical UV filters are below 500 Daltons.
Many studies confirm the basic physiologic premise. 95.8% of Americans had benzophenone (oxybenzone) in urine from its pervasive use in sunscreens and cosmetics (CDC 2008). An EU study from 2010 showed that 85.2% of nursing mothers had at least one UV filter in breast milk. Oxybenzone was found in the urine (99%) and amniotic fluid (61%) of patients having 3rd trimester amniocentesis (CDC 2012).
Recent studies confirm the widespread contamination of humans with soluble UV filters found in blood, urine, amniotic fluid, placenta, fetal and cord blood, semen, ovarian follicular fluid, and adipose tissue. The entire global water supply, terrestrial, aquatic and marine biota are all polluted with these petrochemical UV filters.
Extensive recent literature confirms the same pattern and prevalence for adverse effects in humans and wildlife from organic UV filters, which have become bioavailable through permeation or ingestion, and are of particular concern when exposure occurs pre-conception, during pregnancy or nursing, infancy and childhood, and adolescence or puberty.
Permeation and bioavailability in humans are now established facts, confirmed and acknowledged by the US Food & Drug Administration (FDA). My literature review, suggests that 6-11% of the amount applied to skin is absorbed into blood, also confirmed by FDA studies in levels exceeding the FDA threshold for toxicity testing. The FDA reiterated the concern in 40 years of scientific literature for hormone disruption and other adverse effects in wildlife and now humans. The FDA now list 12 of these soluble hydrocarbon UV filters as having insufficient data to support the categorization of Generally Regarded As Safe or Effective (GRASE). These include avobenzone, oxybenzone, homosalate, octisalate, octocrylene, octinoxate, meradimate, cinoxate, padimate O, ensulizole, dioxybenzone, and sulisobenzone. Only the INSOLUBLE inorganic mineral UV filters zinc oxide and titanium dioxide have the evidence to support the positive GRASE category given by the FDA.
Of equal concern are the widespread effects on the environment – terrestrial, aquatic and marine. There appears to be a common pathway for toxicity to humans, wildlife, and the marine eco-system. First PERMEATION then HORMONE DISRUPTION, DNA mutation and genotoxicity. Coral has an epidermis similar to human skin but less complex, and an unintended consequence of human use of soluble hydrocarbon UV filters may be the degradation of the terrestrial and marine habitats.
Despite 5 decades and hundreds of reports from all corners of the globe showing that the same effects occur in wildlife and in humans, there is still a chorus arguing “more research is needed”. This position is like revolving door or ‘rabbit hole’ in my opinion and ignores the first precept in medicine “Do No Harm” and the dictates of the Precautionary Principle to err on the side of caution when human health is threatened by a chemical or drug. The Precautionary Principle asserts “that the burden of proof for potentially harmful actions by industry or government rests on the assurance of safety and that when there are threats of serious damage, scientific uncertainty must be resolved in favor of prevention”. This approach is in perfect harmony with the physician’s first rule - primum non nocere” (first do no harm), particularly when faced with serious irreversible consequences from soluble bioavailable UV filters to exposed individuals and their progeny. The Precautionary Principle recognizes that the absence of full scientific certainty shall not be used as a reason for postponing decisions, where there is even minimal risk of serious or irreversible harm.
There is little evidence that sunscreens using soluble petrochemical UV filters - in theory or in practice - can prevent skin cancer. Contemporary science establishes UVA as a primary driver of skin cancer. Avobenzone is the only one of the 12 FDA watchlisted UV filters with any UVA filtering activity and mixtures of these filters - give asymmetric protection transmitting up to 10 times more UVA than UVB to skin - a significant UVB bias. This inadequate UVA protection explains why using petrochemical UV filters over 60 years for sun protection parallels the unrelenting rise in global skin cancer rates, which have doubled or tripled in many countries since 1960. From 1970 to 2009, the incidence of melanoma increased by 8-fold among young women and 4-fold among young men, and in the USA, one person dies of melanoma every 54 minutes. Skin cancer is now the most common cancer in the USA and in Canada, and accounts for more than 50% of all human cancers i.e. skin cancer cases outnumber all other cancers combined. Melanoma is the leading cause of cancer death in women ages 25-30, the second leading cause of cancer death in women ages 30-35, and melanoma is the second most commonly diagnosed cancer age 15-29.
The cornerstone of clinical medicine and epidemiology is Benefit Risk Assessment (BRA). This analysis has yet to be applied stringently to the common use of UVB-BIASED sunscreens using mixtures of soluble organic UV filters in the face of a steady rise in all forms of global skin cancer. Sunscreen label claims are largely based on the assumption that sunscreens could prevent sunburn and by extrapolation skin cancer and other forms of sun damage. They were never preceded by the mandatory rigorous clinical research trials looking at the BRA equation and adverse effects of hormone disruption, and genotoxic or mutagenic effects.
Since there is no defined benefit provided by sunscreens using these filters, then unintended human and wildlife toxicity become more significant. Definitive fetal toxicity studies to identify mutagenic, epigenetic effects, or to assess the NOAEL (No Observed Adverse Effect Level) in a fetus are either unethical, impractical, and close to impossible. The BRA for soluble organic UV filters have little benefit to the mother in discernible population based reduction of skin cancer for the mother and has only risk to the fetus and no intended benefit.
The Endocrine Society and others document the widespread and varied effects on human health of many hormone disruptors - irreversible or in some instances transgenerational - reproductive disorders - infertility, cancers (breast, prostate, testicular), genital malformations, defects in gametogenesis, endometriosis, uterine fibroids, anddisorders of puberty - other endocrine and metabolic problems – thyroid cancer, Type 2 diabetes, metabolic syndromes and obesity, and to autoimmune and neurological problems – Alzheimer’s , Parkinson’s, ADHD, autism spectrum disorders, and childhood asthma. Reports do not single out Soluble UV Filters, but mention cosmetics as a group. Soluble UV filters have become the leading source of exposure to an Endocrine Disrupting Chemical (EDC) in developed societies where sunscreen use is highest. The germline epigenetic disorders in future generations remain unclear and will likely never be accurately defined. The fetus is the most vulnerable human.
Fetal effects are often serious and may be irreversible – birth weight disorders, spina bifida, Hirschsprung’s Disease (a newborn intestinal problem), issues with puberty and reproductive disorders as an adult, and problems with the early placenta leading to higher rates of miscarriage and pregnancy disorders. Whatever the risks, any prudent parent or expectant mother will exercise their own PRECAUTIONARY approach.
I believe that every human should absolutely avoid these petrochemical UV filters. Eventually, the FDA and others will develop a regulatory framework from valid evidence ofsafety and efficacy beyond a reasonable doubt. While it evolves, a good place to start would be with a WARNING Label on BIOAVAILABILITY and a CAUTION to pregnant or nursing mothers and others who may be more at risk – young or adolescent children, and couples trying to conceive. This occurs for almost everything that is bioavailable to vulnerable groups, particularly the fetus, including low dose aspirin and many other OTC non-prescription items, such as vitamins, cigarettes, and alcohol. A Warning Label is justified based on the absolute proof of bioavailability, and allows the consumer to make their own informed choice.
The alternative – use sunscreens with large molecular weight INSOLUBLE filters – inorganic zinc oxide, titanium dioxide, organic bemotrizinol, bisoctrizole, and drometrizole trisiloxane, which exceed the 500 Dalton threshold for permeation through human skin. This avoids the bioavailability underlying any risks for the adverse effects seen with SOLUBLE petrochemical UV filters. These insoluble filters include the most efficient UVA filters and provide better balanced UVA/UVB protection against skin cancer and keeps you looking younger for longer. More BENEFIT– virtually ZERO RISK. The Precautionary Principle applied - and a better BRA equation for humans, wildlife and the environment.
Denis K. Dudley MD, FRCS(C), Board Certified in OB-GYN, USA, Canada, Great Britain. Sub-Specialty Practice in Maternal Fetal Medicine & Reproductive Endocrinology, May 2020