2D structural formula of Thiomersal


What is it?

“Thiomersal (INN), or thimerosal (USP), is an organomercury compound with the chemical formula C9H9HgNaO2S.” Wikipedia

What are the effects?

This substance belongs to the groups:

Thiomersal (and other mercury compunds) are prohibited for use in cosmetics in Canada and the EU. Mercury compounds are restricted for use in cosmetics in the U.S.

The U.S. Food and Drug Administration (FDA) writes about mercury compounds;
“The toxicity of mercury compounds is extensively documented in scientific literature. It is well known that mercury compounds are readily absorbed through the unbroken skin as well as through the lungs by inhalation and by intestinal absorption after ingestion. Mercury is absorbed from topical application and is accumulated in the body, giving rise to numerous adverse effects. Mercury is a potent allergen and sensitizer, and skin irritation is common after topical application. Cosmetic preparations containing mercury compounds are often applied with regularity and frequency for prolonged periods. Such chronic use of mercury-containing skin-bleaching preparations has resulted in the accumulation of mercury in the body and the occurrence of severe reactions. Recently it has also been determined that microorganisms in the environment can convert various forms of mercury into highly toxic methyl mercury which has been found in the food supply and is now considered to be a serious environmental problem.”

The European Chemicals Agency (ECHA) identifies that thiomersal “is fatal if swallowed, is fatal if inhaled, is fatal in contact with skin, is very toxic to aquatic life with long lasting effects, and may cause damage to organs through prolonged or repeated exposure.”

Thiomersal is on the Red List* from Campaign for Safe Cosmetics, a project of Breast Cancer Prevention Partners (previously the Breast Cancer Fund).

* “The Red List includes chemicals found in personal care products that pose serious, chronic health concerns including cancer, hormone disruption, and reproductive and developmental harm. The list also flags chemicals that are banned or have use restrictions by the U.S. or other world governments, ingredients that adversely impact worker health, and ingredients that are widely used in products marketed to women of color.” – Campaign for Safe Cosmetics

How is it used?

Thiomersal (INN) is used as a preservative, antiseptic and antifungal agent in cosmetics and in some vaccines. The compound is based on mercury.

The use of INN in vaccines is surrounded by some controversy, while scientists argue that it is safe to use, popular fear exists. Some countries like the US and the EU do not longer use INN in routine child vaccinations. But the UN, among others, has concluded that there is no evidence of toxicity and that switching to another alternative would be too expensive for developing countries.

We use the European Commissions definition of Cosmetics:
“Cosmetics range from everyday hygiene products such as soap, shampoo, deodorant, and toothpaste to luxury beauty items including perfumes and makeup”.

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