Oxybenzone or benzophenone-3 or BP-3 (
trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3) is an
organic compound. It is a pale-yellow solid that is readily soluble in most organic solvents. Oxybenzone belongs to the class of aromatic
ketones known as
benzophenones. It is widely used in plastics, toys, furniture finishes, and other products to limit UV degradation.
Sunscreens containing Oxybenzone have been banned from sale in Hawaii since 2021
due to its environmental effects, such as mortality in developing coral, coral bleaching, genetic damage to coral and marine organisms.
NGO's such as EWG, the
Environmental Working Group
The Environmental Working Group (EWG) is an American activist group that specializes in research and advocacy in the areas of agricultural subsidies, toxic chemicals, drinking water pollutants, and corporate accountability. EWG is a nonprofit ...
, have petitioned the US FDA to ban the ingredient citing hormonal disruption, cancer related concerns and the FDA's previous ruling in 2021 declaring that it is not
GRASE (Generally Recognised As Safe and Effective).
Structure and electronic structure
Being a
conjugated molecule, oxybenzone absorbs light at lower energies than many aromatic molecules.
As in related compounds, the
hydroxyl group is hydrogen bonded to the ketone.
This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the
phosphorescence and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH.
Production
Oxybenzone is produced by
Friedel-Crafts reaction of
benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula . It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring () with an acyl chloride () substituent. It is ...
with
3-methoxyphenol.
Uses
Oxybenzone is used in plastics as an ultraviolet light absorber and stabilizer.
It is used, along with other
benzophenone
Benzophenone is the organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. It is a white solid that is soluble in organic solvents. Benzophenone is a widely used building block in organic chemistry, being the parent diarylket ...
s, in sunscreens, hair sprays, and cosmetics because they help prevent potential damage from sunlight exposure. It is also found, in concentrations up to 1%, in nail polishes.
Oxybenzone can also be used as a photostabilizer for
synthetic resins
Synthetic resins are industrially produced resins, typically viscous substances that convert into rigid polymers by the process of curing. In order to undergo curing, resins typically contain reactive end groups, such as acrylates or epoxides ...
.
Benzophenones can leach from food packaging, and are widely used as photo-initiators to activate a chemical that dries ink faster.
It is also found in nail polish, fragrances, hairspray, and cosmetics as a photostabilizer. Despite its photoprotective qualities, much controversy surrounds oxybenzone because of its possible hormonal and photoallergenic effects, leading many countries to regulate its use.
Sunscreen
Oxybenzone is used in 70% of sunscreen products.
The European Food Safety Authority categorises benzophenone, such as oxybenzone, as persistent, bio-accumulative, toxic and as a possible human carcinogen and endocrine disruptor. It can penetrate the skin to accumulate in the bloodstream. As a sunscreen, it provides broad-spectrum ultraviolet coverage, including
UVB
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
and short-wave
UVA
UVA most often refers to:
* Ultraviolet A, a type of ultraviolet radiation
* University of Virginia, a public research university in Charlottesville, Virginia, United States
Uva or UVA may also refer to:
Places
* Uva, Missouri, an unincorpora ...
rays. As a
photoprotective agent, it has an
absorption
Absorption may refer to:
Chemistry and biology
*Absorption (biology), digestion
**Absorption (small intestine)
*Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials
*Absorption (skin), a route by which s ...
profile spanning from 270 to 350 nm with absorption peaks at 288 and 350 nm.
Some brands market their sunscreens as "oxybenzone free" due to the negative perception of benzophenones
Safety
U.S. FDA designation 2021
In 2021 the U.S. FDA changed their classification of oxybenzone and now regard it as not
GRASE, Generally Recognised As Safe and Effective
due to the lack of data to support its safety despite it being the most common UV petrochemical filter
and being used in sunscreens since the 1980s.
''In vivo'' studies
The incidence of oxybenzone causing photoallergy is extremely uncommon,
however, oxybenzone has been associated with rare allergic reactions triggered by sun exposure. In a study of 82 patients with photoallergic contact
dermatitis, just over one quarter showed photoallergic reactions to oxybenzone. Evidence points to Oxybenzone having
contact allergen
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.
In technical terms ...
effects.
Oxybenzone is allegedly the most common allergen found in sunscreens.
In a 2008 study of participants ages 6 and up, oxybenzone was detected in 96.8% of urine samples. Humans can absorb anywhere from 0.4% to 8.7% of oxybenzone after one topical application of sunscreen, as measured in urine excretions. This number can increase after multiple applications over the same period of time.
Oxybenzone is particularly penetrative because it is the most
lipophilic of the three most common UV filters.
When applied topically, UV filters, such as oxybenzone, are absorbed through the skin, metabolized, and excreted primarily through the urine.
The method of
biotransformation Biotransformation is the biochemical modification of one chemical compound or a mixture of chemical compounds. Biotransformations can be conducted with whole cells, their lysates, or purified enzymes. Increasingly, biotransformations are effected w ...
, the process by which a foreign compound is chemically transformed to form a metabolite, was determined by Okereke and colleagues through oral and dermal administration of oxybenzone to rats. The scientists analyzed blood, urine, feces, and tissue samples and found three metabolites: 2,4-dihydroxybenzophenone (DHB), 2,2-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxybenzophenone (THB). To form DHB the methoxy functional group undergoes O-dealkylation; to form THB the same ring is hydroxylated.
Ring B in oxybenzone is hydroxylated to form DHMB.
A study done in 2004 measured the levels of oxybenzone and its metabolites in urine. After topical application to human volunteers, results revealed that up to 1% of the applied dose was found in the urine.
The major metabolite detected was DHB and very small amounts of THB were found.
By utilizing the
Ames test in ''Salmonella typhimurium'' strains, DHB was determined to be nonmutagenic. In 2019, the
U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...
(FDA) noted in their recommendations for future study that, "While research indicates that some topical drugs can be absorbed into the body through the skin, this does not mean these drugs are unsafe." Despite Oxybenzone being a found in some plants it is considered highly toxic.
Environmental effects
Studies and governmental agencies link oxybenzone exposure to mortality in developing coral,
coral bleaching
Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae ( dinoflagellates that are commonly referred to as ...
, and genetic damage to coral and marine life.
Widespread studies have led to the ban of oxybenzone-containing sunscreen in many areas such as
Palau,
Hawaii, nature reserves in
Mexico,
Bonaire
Bonaire (; , ; pap, Boneiru, , almost pronounced ) is a Dutch island in the Leeward Antilles in the Caribbean Sea. Its capital is the port of Kralendijk, on the west (leeward) coast of the island. Aruba, Bonaire and Curaçao form the ABC isla ...
, the
Marshall Islands, the
United States Virgin Islands, Thailand's marine natural parks, the
Northern Mariana Islands, and
Aruba
Aruba ( , , ), officially the Country of Aruba ( nl, Land Aruba; pap, Pais Aruba) is a constituent country of the Kingdom of the Netherlands physically located in the mid-south of the Caribbean Sea, about north of the Venezuela peninsula of ...
.
Health and environmental regulation
Aruba
Banned the use of Oxybenzone in sunscreens due to environmental concerns in 2019
Australia
Revised as of 2007, the
National Industrial Chemicals Notification and Assessment Scheme (NICNAS) Cosmetic Guidelines allow oxybenzone for cosmetic use up to 10%.
Canada
Revised as of 2012,
Health Canada
Health Canada (HC; french: Santé Canada, SC)Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the department of the Government of Canada responsible for national health polic ...
allows oxybenzone for cosmetic use up to 6%.
European Union
The
European Food Safety Authority
The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
categorises benzophenone, such as oxybenzone, as persistent, bio-accumulative, toxic and as a possible human carcinogen and endocrine disruptor. The
Scientific Committee on Consumer Products (SCCP) of the
European Commission concluded that it poses significant risk to consumers as a contact allergenic potential.
It is allowed in sunscreens and cosmetics at levels of up to 6% and 0.5% respectively. "A recent revision amendment introduced by the Opinion of the European Commission’s Scientific Committee on Consumer Safety recommended the reduction of the current maximum concentration of oxybenzone in a consumer product from 6% to 2.2% because of reproductive, developmental, and carcinogenic concerns."
Japan
Revised as of 2001, the
Ministry of Health, Labour, and Welfare
The is a cabinet level ministry of the Japanese government. It is commonly known as in Japan. The ministry provides services on health, labour and welfare.
It was formed with the merger of the former Ministry of Health and Welfare or and the ...
notification allows oxybenzone for cosmetic use up to 5%.
Palau
The Palau government has signed a law that restricts the sale and use of sunscreen and skincare products that contain oxybenzone, and nine other chemicals. The ban came into force in 2020.
Sweden
The
Swedish Research Council
The Swedish Research Council ( sv, Vetenskapsrådet) is a Government agency in Sweden established in 2001, with the responsibility to support and develop basic scientific research. Its objective is for Sweden to be a leading nation in scientif ...
has determined that sunscreens with oxybenzone are unsuitable for use in young children, because children under the age of two years have not fully developed the enzymes that are believed to break it down. No regulations have come of this study yet.
United States
In 2021 the U.S.
Food and Drug Administration, U.S. FDA, changed their classification of Oxybenzone and do not recognize it as
GRASE, Generally Recognised As Safe and Effective.
The FDA only allows oxybenzone in OTC sunscreen products up to 6%.
The
Hawaii State Legislature has legislated oxybenzone as illegal for use in
sunscreens and personal care products since 2021 due to its environmental effects, such as mortality in developing coral, coral bleaching, genetic damage to coral and other marine organisms.
Key West has also banned the sale of sunscreens that contain the ingredients oxybenzone (and
octinoxate
Octyl methoxycinnamate or ethylhexyl methoxycinnamate (INCI) or octinoxate (United States Adopted Name, USAN), trade names Eusolex 2292 and Uvinul MC80, is an organic compound that is an ingredient in some sunscreens and lip balms. It is an este ...
). The ban was to be effective as of January 1, 2021. However, this legislation was superseded by the
Florida State Legislature by Senate Bill 172, which prohibits local governments from regulating over-the-counter proprietary drugs and cosmetics (such as sunscreen containing oxybenzone and octinoxate). The statute became effective July 1, 2020.
The City of
Miami Beach, Florida voted against a ban of oxybenzone, with commissioners citing public health concerns and lack of clarity on scientific evidence supporting such a ban.
Oxybenzone is listed on California's Proposition 65 chemicals that are known to cause cancer and / or reproductive toxicity.
References
{{sunscreening agents
Benzophenones
Sunscreening agents
Phenols
Phenol ethers
3-Hydroxypropenals within hydroxyquinones
Environment articles needing expert attention