Olfactory receptor OR2AT4 regulates human hair growth.

Nat Commun. 2018 Sep 18;9(1):3624. doi: 10.1038/s41467-018-05973-0.
Olfactory receptor OR2AT4 regulates human hair growth.
Chéret J1, Bertolini M1,2, Ponce L1, Lehmann J1, Tsai T3, Alam M1, Hatt H3, Paus R4,5.

Olfactory receptors are expressed by different cell types throughout the body and regulate physiological cell functions beyond olfaction. In particular, the olfactory receptor OR2AT4 has been shown to stimulate keratinocyte proliferation in the skin. Here, we show that the epithelium of human hair follicles, particularly the outer root sheath, expresses OR2AT4, and that specific stimulation of OR2AT4 by a synthetic sandalwood odorant (Sandalore®) prolongs human hair growth ex vivo by decreasing apoptosis and increasing production of the anagen-prolonging growth factor IGF-1. In contrast, co-administration of the specific OR2AT4 antagonist Phenirat® and silencing of OR2AT4 inhibit hair growth. Together, our study identifies that human hair follicles can engage in olfactory receptor-dependent chemosensation and require OR2AT4-mediated signaling to sustain their growth, suggesting that olfactory receptors may serve as a target in hair loss therapy.

Full Study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143528/

This is an interesting study. Could we derive a safe protocol from the paper?
Questions would be about quantity, carrier and safety…

Quantity:
Is the concentration of 500 µM per liter, per ml?
Sandalore (C14H26O) weighs 210.36 g/mol. 500µM represent 0.01g but I could not find what volume was used.

Vehicle:
Ex-vivo results were observed with 0.1% DMSO as a carrier on human skin samples ( concentrations below 100μM failed to activate OR2AT4)
Would emu-oil be an acceptable substitue to DMSO?

Safety:
Sandalore® did not exhibit carcinogenicity.
However, the material safety data sheet states "in case of skin contact, remove contaminated clothing and shoes. Wash effected area thoroughly with soap."
Can we assume it is safe topically at the concentration used for the study?


EDIT: found a good thread on this here:
https://www.hairlosstalk.com/interact/threads/sandalore-chemical-used-in-perfumes-to-mimic-sandalwood-triggers-growth.117273/