Allyl Isothiocyanate vs. Capsaicin

I love all sorts of spicy foods — from Sriracha to homemade salsa, to wasabi and hot Chinese mustard. But even those who eat chili pepper-base spicy foods every day and consider themselves to have a high tolerance will find their eyes watering and their sinuses flaring when they eat wasabi.

That’s because unlike chili peppers, wasabi isn’t high in capsaicin, the common spicy chemical that makes your tongue burn. Instead, wasabi is spicy because of a chemical compound called allyl isothiocyanate.

Allyl isothiocyanate vs. capsaicin

You might describe your body’s natural reactions to allyl isothiocyanate and capsaicin both as “spicy” — but they are undoubtedly different experiences.

What is allyl isothiocyanate?

Allyl isothiocyanate is a natural chemical compound that is often described as being spicy. When certain plants are chewed, cells are damaged, releasing enzymes that degrade into allyl isothiocyanate. Initially this chemical reaction evolved to deter animals from eating the plant.

What foods have allyl isothiocyanate?

Wasabi, horseradish, and spicy mustards are the most common foods that you will find containing high levels of allyl isothiocyanate. But it is also found in other members of the Brassicaceae family, like cabbage and cauliflower — in much lower quantities.

What does it feel like to consume allyl isothiocyanate?

Allyl Isothiocyanate is volatile, meaning that it vaporizes easily, which is why breathing out while you are chewing wasabi or horseradish will create an intense nasal burning. Your nasal cavities have TRPA1 receptors, which send pain signals to the brain when they detect the presence of allyl isothiocyanate.

Similarities and differences between allyl isothiocyanate and capsaicin

Both capsaicin and allyl isothiocyanate are natural chemicals found in vegetables that are commonly described as being “spicy”. However, the experience of spice is very different between the two. While capsaicin creates a painful and tingling sensation on your tongue, allyl isothiocyanate creates a painful spicy feeling inside of the sinuses.

The two chemical compounds are also found in different foods — capsaicin creates the spicy effect of chili peppers, while allyl isothiocyanate is what makes horseradish, wasabi, and mustard spicy.