Many massage therapists utilize aromatherapy—the use of specific essential oils’ scents to effect health and healing—during sessions, and much research into aromatherapy has shown it to benefit a variety of conditions. New research illuminates how our sense of smell works.

Among the studies on aromatherapy, researchers have found aromatherapy massage to be an effective treatment for menopausal symptoms; to effect short-term relief of cancer patients’ anxiety and depression; to have general health benefits; and to improve sleep in advanced cancer patients.

When odor-producing molecules, known as odorants, pass through the nose, they trigger intracellular changes in a subset of the approximately 400 different varieties of olfactory sensory neurons housed in the nose’s internal membrane tissue. The unique reaction pattern produced, known as the olfactory code, is sent as a signal to the brain, which leads to perception of odors.

Researchers at The City College of New York studied how these receptor cells respond when odorants change their shape, and found that shape changes in aroma-producing molecules determine the fragrances we detect.

Their findings were reported in the journal “Chemistry & Biology.”