Citronellol

Citronellol is a fragrant, volatile, liquid compound that can be found naturally in many essential oils (especially lemongrass essential oil). It has a pleasant scent and is added as a fragrant compound to many skincare products.

Citronellol is a molecule that demonstrates the sensitivity of our sense of smell to different chemical structures incredibly well. It is a molecule that can be oriented in space in two different ways (this phenomenon is called stereoisomerism).

Each Citronellol isomer is shaped only slightly differently, but with enough of a difference that our noses register them as having different scents. (+)-Citronellol has a distinct lemon-like scent and is found mainly in lemongrass, while (-)-Citronellol smells like roses and is found in rose and geranium oils.

When left unsealed, citronellol, like most other fragrance compounds and essential oils, can oxidize and form allergenic compounds. People with sensitive skin should thus try to avoid products containing citronellol, or at least do a patch test before using.