People with certain types of baldness might be able to sniff their way back to a head of hair. In a study that was published in Nature Communications, researchers found that the scent of synthetic sandalwood, found in perfumes and cosmetics, can stimulate hair growth.
According to Inverse:
The study, sponsored in part by Giuliani Pharma S.p.A. — an Italian pharmaceutical company that sells the synthetic sandalwood treatments — showed that the cells surrounding the root of every hair can "smell" synthetic sandalwood and, more importantly, respond to the smell…
Hair follicles, the small cluster of cells that surround the root of every hair, contain a molecule sensor called OR2AT4, which is found all over the body but is best known for its role in the nose. Usually, it gets stimulated by scent molecules in the nose and goes on to trigger a chain reaction that results in the perception of smell. But as it turns out, OR2AT4 receptors still get excited by scent even when they're on your head…
In this study, Paus found that exposing the hair follicles (and their OR2AT4 receptors) to synthetic sandalwood prolonged the growing phase of the hair cycle by mediating a key molecule that drives the hair cycle forward: a protein called IGF-1 (insulin-like growth factor 1). He posits that exposing OR2AT4 to Sandalore creates more IGF-1, which in turn tends to stop the cells from dying in phase two, theoretically keeping them growing in phase one.
Interestingly, it's the synthetic version of sandalwood (Sandalore), and not natural sandalwood, that does the trick.