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Problems associated with sunscreens

In sunscreens, a distinction is essentially made between two mechanisms of action:


1. Sunscreens with mineral or physical UV filtering


These products contain substances such as titanium dioxide (TiO2) and zinc oxide (ZnO). When applied, these stick to the skin and, through diffuse reflection, guard against UV radiation on the skin. Today, these are frequently added in the form of nanoparticles (nano-titanium dioxide and nano-zinc oxide) in order to avoid a whitening effect.

The Biocides Regulation defines nanomaterials as “particles (…) where 50 percent or more of the particles have a size of 1 nm to 100 nm in at least one dimension.”


Zinc oxide

A publication from 2018 was unable to detect any skin permeability for hydrophobic silicone-coated and uncoated zinc oxide nanoparticles measuring 65 and 77 nm. 

However, a study from 2010 concluded that the absorption of nanoparticles through the skin is influenced by particle size and that this also depends on the skin’s state of health. In the ECHA database, zinc oxide is listed as highly toxic to aquatic life.


Titanium dioxide

The Scientific Committee on Consumer Safety (SCCS) establishes that, on the basis current data and the possible classification of titanium dioxide under the CLP Regulation as a Category 2 carcinogen (inhalation), the use of pigmented titanium dioxide in topical preparations is not safe for the general consumer when inhaled. In the ECHA database, titanium dioxide is listed as a possible carcinogen. 


Since 11 July 2013, nanoparticles in cosmetics have been subject to mandatory labelling in the EU.

Update for titanium dioxide 07 May 2021

Titanium dioxide is also used as a whitening agent in foodstuffs (sweets, toothpaste, mozzarella etc.) and drugs. According to a publication by the German Federal Institute for Risk Assessment (BfR) dated 06 May 2021, use as a food additive is not regarded as safe, since titanium dioxide is strongly suspected of being mutagenic. Titanium dioxide has been banned in foodstuffs in France since 1 January 2020.


2. Sunscreens with chemical UV filtering


These substances penetrate the skin. They contain absorbent substances that convert the energy of UV radiation into infrared light and re-emit it. Some of these chemical UV filters are strongly suspected of being endocrine disruptors. The following substances and substance groups are currently under scrutiny by the European Commission:



These UV filters pass from the body into the environment through direct contact with bodies of water or indirectly via sewage treatment facilities into the ocean. They accumulate in bodies of water, are not biodegradable and increasingly accumulate in the food chain. They have been proven to be toxic to  aquatic organisms such as corals.

Because they are held responsible for coral bleaching worldwide, sunscreens with the above-named UV filters have been banned on Palau since 2020 and in accordance with the Hawaii Reef Act (SB 2571) are banned on Bonaire, in Key West, Florida, the American Virgin Islands, Hawaii, Thailand and the Yucatan peninsula/Mexico since 1 January 2021.


The EU Commission has drawn up a separate list of 28 substances suspected of having an endocrine effect in humans. In Europe, the evaluation of the hazard posed to the environment by UV filters in cosmetics and other products is currently taking place under the European REACH Regulation (EC No. 1907/2006)


The Haereticus Environmental Laboratory (USA) has developed the Protect Land + Sea Certification that certifies safe sunscreens. Sunscreens must also not contain any microplastics, nanoparticles or triclosan.

According to current knowledge, numerous sunscreen creams and sprays available on the market still contain oxybenzone, octocrylene, octinoxate and parabens.

© Dr. med. Dipl. Biol. Susanne Saha 03/2021




>> As an additional link, the article by Prof. Peter and Prof. Joachim Barth from Altmeyer’s Encyclopaedia: Vierzehntausend Tonnen oder wer liebt das Meer? <<

>>Download our information sheet on sunscreens from Dr. med. Christina Hecker for your patients <<

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