Benzophenone-3 provides effective protection against both UVA and UVB radiation. The substance has been available since the 1980s.
“There has been a certain amount of discussion about Benzophenone-3, and it is for this reason not common in Swedish sunscreens. This is a shame, since there are few substances that protect as effectively against UVA radiation”, says dermatologist Helena Gonzalez.
It is known that benzophenone-3 can cause contact eczema, but there is limited knowledge about other adverse effects.
Helena Gonzalez carried out a study in which 26 people applied sunscreen containing 4% benzophenone-3 to the complete skin morning and evening for five days. These people supplied a urine specimen every day.
“We designed the study such that it was similar to what is normal when people take a normal holiday in the sun”, says Helena Gonzalez.
The subjects continued to provide urine specimens after they stopped applying the sunscreen. The urine still contained benzophenone-3 five days after stopping using the sunscreen, a result that suggests that the substance is being stored in the body. The average total amount of benzophenone-3 excreted was 3.7%.
“We don’t know how long it is stored, and we don’t known whether it is important, but I suggest that parents of small children should avoid using sunscreens that contain benzophenone-3, to be on the safe side”, says Helena Gonzalez.
Children under the age of two years have not fully developed the enzymes that are believed to break down benzophenone-3. This suggests, in theory, that small children will not be able to get rid of the substance as easily as adults.
The thesis also shows that several common sunscreens break down under the action of sunlight. Several sunscreens that are readily available in the shops were tested, and their photostabilities were measured after 30, 90 and 120 minutes. The protection against UVA radiation deteriorated by more than 20% for three of these sunscreens. This deterioration took place for one sunscreen after only 30 minutes.
“The principal protection against the harmful effects of the sun should be clothes,” says Helena Gonzalez, “and sunscreens should be used solely as a supplement.”
Some of the commercial sunscreens have changed their composition after the test was carried out, and it is not known whether the new formula has better photostability than the old.Thesis presented for the title Doctor of Medicine at the Sahlgrenska Academy, Department of Clinical Sciences, Department of Dermatology and Venereology
The title of the thesis: Studies of Sunscreens: Percutaneous Absorption of Benzophenone-3 and Photostability
The thesis will be defended on Friday 10 November, 9.00 a.m., Lecture Theatre “Arvid Carlsson”, Academicum, Medicinaregatan 3, Göteborg, Sweden.
Elin Lindström Claessen | alfa
Collagen nanofibrils in mammalian tissues get stronger with exercise
14.12.2018 | University of Illinois College of Engineering
New discoveries predict ability to forecast dementia from single molecule
12.12.2018 | UT Southwestern Medical Center
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy