Tanning activators are chemicals that increase the effect of

UV-radiation 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 ...

on the

human skin The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most ...

Overview

Since

sunburn Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and animals include: red or reddish skin that is ho ...

and suntan are induced by the same mechanism (

direct DNA damage Direct may refer to: Mathematics * Directed set, in order theory * Direct limit of (pre), sheaves * Direct sum of modules, a construction in abstract algebra which combines several vector spaces Computing * Direct access (disambiguation), ...

), these substances increase the likelihood for sunburn as well. The best known tanning activator is

psoralen Psoralen (also called psoralene) is the parent compound in a family of naturally occurring organic compounds known as the linear furanocoumarins. It is structurally related to coumarin by the addition of a fused furan ring, and may be considered ...

which is an ingredient of bergamot oil. Psoralen has been present in

sunscreen Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn and ...

s in order to allow suntanning despite the reduced UV-intensity that acts on the deeper layers of the skin. In

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

, a ban was imposed on psoralen containing sunscreens in 1987 but it was loosely enforced for several years. In other countries these substances have been present in sunscreens until the first epidemiological results have shown that users have a fourfold risk of developing melanoma. They were finally banned in 1996. This happened more than 15 years after the

photocarcinogen A photocarcinogen is a substance which causes cancer when an organism is exposed to it, then illuminated. Many chemicals that are not carcinogenic can be photocarcinogenic when combined with exposure to light, especially UV. This can easily be un ...

ic potential of psoralen had been demonstrated. After the evidence for the photocarcinogenic potential of psoralen emerged, sunscreens which combined UVB filters and psoralen were introduced onto the market. These products were accompanied by campaigns to convince the public and the regulatory authorities that these products were safe or even better than usual sunscreens. These sunscreens were especially recommended to poor tanners. Psoralen tanning lotions were available in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

and

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

Mechanism of tanning activators

The increased production of melanin is the reaction of the skin to UVB-induced

. Several substances are known to increase the amount of direct DNA damage (

thymine dimers Pyrimidine dimers are molecular lesions formed from thymine or cytosine bases in DNA via photochemical reactions, commonly associated with direct DNA damage. Ultraviolet light (UV; particularly UVB) induces the formation of covalent linkages betwe ...

). In order to produce this action they have to penetrate into the skin, and this is in contrast to the assumptions which are made by those who endorse sunscreen use (see

sunscreen controversy Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn a ...

). The tanning activator

coumarin Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by a lactone-like chain , forming a second six-membered h ...

is known to induce thymine dimers (cyclobutane pyrimidine dimers).{{cite journal , author=B. M. Hausen , author2=M. Schmieder , title=The sensitizing capacity of coumarins (I) , journal=Contact Dermatitis , volume=15 , issue=3 , pages=157–163 , year=1986 , pmid= 3780217, doi=10.1111/j.1600-0536.1986.tb01317.x Other Web sites state correctly that: "Coumarins produce photosensitivity therefore advise the patient to avoid direct sunlight after treatment

References

Sun tanning

Overview

Mechanism of tanning activators

See also

References