Synthetic sandalwood, better known for its role as sock-drawer potpourri, had unexpected effects on hair regrowth in a recently released study in Nature Communications. But although the application of this study has to do with regrowing hair on your head, the science behind it has more to do with sensors usually associated with your nose.

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.

“This is actually a rather amazing finding,” University of Manchester cutaneous medicine professor and study author Ralf Paus, Ph.D., tells Inverse in an email. “This is the first time ever that it has been shown that the remodeling of a normal human mini-organ (hair) can be regulated by a simple, cosmetically widely used odorant. And this is a strictly receptor-dependent manner.”

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.

sandalwood incense
Synthetic sandalwood is often found in commercial scented products like incense.

Paus explains that this happens because Sandalore (the synthetic sandalwood odorant) can influence the three-part life cycle of hair. In the first phase, a hair starts to grow deep within the hair follicle. During this phase, lots of cells within that follicle turn into cells that form the hair shaft, which can grow for a few months.

In the second phase, the follicle cells slowly stop turning into hair cells and begin to die. Exhausted from all that activity, the follicle then literally ejects the hair shaft from your head and enters a rest period during which it prepares to start the whole cycle over again.

This study investigates Sandalore as an aid to hair growth , which is a “synthetic odorant” that smells a lot like real sandalwood.

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.

hair cycle growth baldness sandalwood
Sandalore did keep a higher percentage of hair follicles in the crucial growth stage, anagen. Catagen is the stage where follicles usually die.

It’s important to know that Sandalore is a synthetic sandalwood product, not natural sandalwood. This is one case in which the synthetic product is better than the original; Paus says that real sandalwood wouldn’t stimulate hair growth “since it does not bind to OR2AT4.” Instead, it’s the synthetic components of the Sandalore product that stimulate this effect. Fortunately, synthetic sandalwood odorants are more prevalent in consumer products.

“Anyway, the synthetic sandalwood-like odorant, Sandalore, is the one that is usually used in cosmetics and perfumes, since natural sandalwood is more expensive and is more sensitizing (i.e. can induce allergy).”

This is promising for certain types of baldness that result from mistiming of the hair cycle — but more studies and clinical trials will have to be done to confirm this. According to Paus, one is happening right now, with results expected to drop around January 2019.

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