The Hidden Dangers of Coumarin-Containing Products

As the inherently toxic white crystalline lactone that gives cinnamon its distinctive aroma, does coumarin-containing products pose a health risk to consumers?


By: Ringo Bones


Thankfully, its chemically distant cousin – vanillin – which is the crystalline phenolic aldehyde that is the chief fragrant component of vanilla used in flavoring and perfumery is yet to be proven as a health hazard. But coumarin, the toxic white crystalline lactone, which in higher purity smells like newly-mown hay, found in cinnamon and mostly manufactured synthetically for use in cosmetics and perfumes. Has been deemed hazardous by the German Federal Institute for Risk Assessment since 2005. In lower concentrations, coumarin is the active component that gives cinnamon and related flavorings their distinctive aroma. Because recent studies have shown that some products – especially cosmetic creams that contain high concentrations of coumarin – results in unfavorably elevated liver enzyme values. And in some cases resulted to jaundice and liver damage. Coumarin is also toxic to the human kidney in sufficient amounts thus making it a definite no-no to those taking cholesterol lowering medication.

Erring on the side of caution, the German Federal Institute for Risk Assessment had urged cosmetic and foodstuff manufacturers to indicate whether their products contain coumarin or not since 2005. Making them probably the first in the world to do so. The established dose limit of coumarin has been set at 0.1 milligrams per kilogram of body weight. So a person weighing 75 kilograms should keep their daily intake of coumarin at below 7.5 milligrams. Although studies are still ongoing whether taking coumarin via the gastro-intestinal tract can result in increased risk for liver damage as opposed to via skin absorption through cosmetic creams.

When it comes to cosmetics and toiletries, coumarin-containing creams pose the most risk because they are not readily rinsed off giving higher concentrations of coumarin ample time to be absorbed by the skin. Unlike soaps which are rinsed right away, while perfumes are only applied to the skin’s surface at lower concentrations. Baby products containing coumarin are a definite no-no because a baby’s skin easily absorbs oil-based chemicals and their liver can’t readily process elevated amounts of toxins. So it’s better to err in the side of caution when it comes to coumarin because even in its natural concentration it hardly qualifies as a poison. But due to larger quantities made possible to industrial scale synthesizing of the chemical, products containing coumarin should carry warning labels.