Androgenetic alopecia (AGA), also known as congenital hair loss, is characterized by the progressive thinning and subsequent loss of hair on the head. This widespread dermatological phenomenon affects both women and men and usually has a negative impact on the quality of life of those affected. Congenital hair loss usually occurs around the age of 20; by the age of 50, almost 50% of men are affected. People affected by congenital hair loss usually suffer a lasting deterioration in their quality of life because of it.

The underlying study demonstrates a groundbreaking connection between human hair follicles, their growth and the olfactory receptor system. Olfactory receptors are the oldest receptors in evolutionary history. They are found throughout the human body and regulate various physiological cell functions. Their role in the function of the sense of smell is probably best known.

But they are also active beyond this: the olfactory receptor OR2AT4, for example, stimulates keratinocyte production.

The underlying study shows that the epithelial tissue of human hair follicles, in particular the outer root sheath, expresses the OR2AT4 receptor. Its specific stimulation by the sandalwood odorant ^Sandalore® prolongs ex vivo human hair growth ex vivo by reducing apopotosis (the so-called “programmed cell death”). In addition, the production of the growth factor IGF-1 is increased, which prolongs the anagen phase of hair growth.

In turn, application of a specific OR2AT4 antagonist in the study suppressed hair growth. This is a clear indication of the specific effect of the sandalwood odorant used on hair growth.

These findings were obtained using several complex test procedures and methods. These include studies using the hair follicle culture model (HOKM), as well as histological examinations and immunofluorescence studies. Furthermore, for example, investigations of protein concentrations using Western blot-method. Finally, in addition to statistical analyses, quantitative (immuno-)histomorphometry using software was also used.

Conclusion

By stimulating the olfactory receptor OR2AT4, the sandalwood odorant used in the study prolongs the anagen phase of hair growth. This occurs through the increased production of the growth factor IGF-1. The stimulation of olfactory receptors represents a new and promising approach in the treatment of hair loss. The sandalwood odorant used in the study proved to have a clear hair growth-promoting effect.

Underlying study:

A. Kramer et al: Chéret, J. et al: Olfactory receptor OR2AT4 regulates human hair growth; in: Nature Communications volume 9, Article number: 3624 (2018).