Hexyl Cinnamal, also known as 2-(Phenylmethylene)-Octanal, Alpha-Hexylcinnamaldehyde, Hexyl Cinnamic Aldehyde, Hexylcinnamic Aldehyde, Octanal, 2(Phenylmethylene), and Octanal, 2-(Phenylmethylene)-, is a naturally occurring and synthetic scent ingredient used in cosmetics​.

It is widely used in cosmetics due to its pleasant, jasmine-like fragrance. However, it is known to be associated with allergic reactions and as such, has a high concern rating for allergies and immunotoxicity​1​. It's known to be a human allergen and a possible human immune system toxicant​1​, and it is restricted in cosmetics due to the labeling requirement for allergens.

Hexyl Cinnamal is included on the EU's list of 26 fragrances that pose an allergenic risk. The regulation of these fragrances applies when the substance content exceeds 0.01 percent of the final product, but in most cases, manufacturers limit themselves to very low dosages to avoid health risks for non-allergic persons​.

For individuals with allergies, even small doses of this ingredient can trigger skin reactions such as redness, hives, itching, or eczema within 24 to 72 hours, with about 11.5 percent of consumers showing allergic reactions to fragrances. Even for susceptible skin, a dose below the limit of 0.01 percent can cause a reaction. In such cases, it's advisable to consult a doctor. Once a contact allergy is established, it is not curable, and the allergenic substance should be avoided in the future​2​. The ingredient is also advised to be avoided by asthmatics and people with hyperreactive (hypersensitive) airway issues​​.

Apart from its allergenic potential, there are concerns about some fragrances, including Hexyl Cinnamal, potentially causing cancer, although this potential risk is not definitively established​.

How safe is it?

Hang tight. We're thinking.