The status of the 24 over-the-counter (OTC) ultraviolet absorbers approved for use since 1978 is on life-support.  If my treatise here does not move the US Food and Drug Administration (FDA), the Personal Care Product Council (PCPC), cosmetic scientists, and even the Public Access to Sunscreens (PASS) Coalition to act, then we are all in deep denial.

Allow me to back track and review the relevant events in history. A panel was convened early in the 1970s to issue a monograph governing the use of sunscreens in the USA.  On August 25, 1978, the first Advanced Notice for Proposed Rulemaking (ANPR) was published by the FDA and it listed 21 UV filters as Category I ingredients (see Table I at right). Note that three additional ingredients were added later on for a total of 24 approved UV filters including avobenzone (September 16, 1996), zinc oxide (October 22, 1998) and ecamsule through a New Drug Application (NDA) issued to L’Oréal (July 24, 2006). 

On May 12, 1993, the Tentative Final Monograph (TFM) was issued and the Final Rule was released in 2011. Yet, there is no Final Monograph. The Final Rule of 2011 listed the 17 Category I Ultraviolet Filters. They are listed in Table II (above, right) with notations signifying if they are UVA/UVB filters, water soluble (WS) or banned in Hawaii.

With the recent developments in Hawaii and the banning of both oxybenzone and octinoxate beginning in 2021, there is potential for a nationwide ban as Congressman Tulsi Gabbard (D-Hawaii) tweeted on July 3, 2018:  “I am working on a legislation to take this ban national.”

There are seven currently usable ultraviolet filters in the US (Table III). Note that only seven ingredients will be used in the US in the near future. The three large aggregated molecules, zinc oxide, titanium dioxide and ecamsule (only for L’Oréal products), are in compliance with the Dalton 500 Rule, which ensures that these UV filters do not significantly permeate the skin. The remaining four UV filters, avobenzone (MW 310), homosalate (MW262), octisalate (MW250) and octocrylene (MW 362) are all smaller molecules of less than 500 Daltons and, hence, possibly penetrate the skin. 
In addition, avobenzone is photo-unstable and is a UVA filter only if adequately formulated and quenched with other UV filters. These quenching UV filters include octocrylene, methyl benzylidene camphor, oxybenzone, polycrylene, Synoxyl HSS, Corapan TQ, Oxynex ST, etc.).  In fact, the Diketo Avobenzone (butyl methoxydibenzoyl methane) has a λmax of around 260nm.  This is neither a UVA nor a UVB filter!  Only its Enol tautomer qualifies it to be a UVA filter with a λmax of 357nm. 

A Grim Future
If, in the future, these four small molecules were eliminated and replaced with the TEA (Time and Extent Application) European UV Filters (see Table IV), we can revolutionize the sunscreen industry and, more importantly, change how ultraviolet filters are classified in the US.  All six TEA ingredients have high molecular weights (MW) and are designed based on the 500 Dalton Rule.

Ensuring that none of the ultraviolet filters used in sunscreen cosmetics penetrate the skin, we will have an excellent case in re-classifying sunscreens as special “cosmetics” instead of “drugs.” Most of the world classifies sunscreens as “cosmetics” with no unusual adverse effects or potential harm to the consumers.

Sunscreens as cosmetics will clear the way for new research, innovation and the introduction of far more superior ingredients (both synthetic and natural) that adequately protect from the ravages of harmful solar radiation. So long as we can ensure that the new filters are large non-skin penetrable ingredients and are both safe and effective, then a host of filters will be produced that will provide protection against UVB, UVA, high energy visible (HEV) and infrared radiation.

If sunscreens are classified as special cosmetics it will undoubtedly ensure the introduction of far more superior ultraviolet filters. Sunscreens will once again be thought of as safe and effective ingredients for protection. Consumers will use them freely without the current shadow of applying ineffective or unsafe sunscreens. Compliance will clearly boost prevention protocols and, hopefully, reduce the spiraling incidence of skin cancer.

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Nadim Shaath
Alpha Research
& Development Ltd
Email: alpharnd@aol.com

Dr. Nadim Shaath is the president of Alpha Research & Development, Ltd. in White Plains, NY. He has over 30 years of experience as chairman of the chemistry department at SUNY-Purchase and the CEO of Kato Worldwide. Recently he published his new book entitled “Healing Civilizations: The Search for Therapeutic Essential Oils and Nutrients” Cameron Books, Petaluma, CA.