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

Currently available active ingredients against congenital hair loss are mainly oral finasteride (butyl-3-oxo-4-aza-5α-androst-1-en-17β-carbamide) and locally applied minoxidil (6-piperidin-1-ylpyrimidine-2,4-diamine 3-oxide). The pyrimidine derivative minoxidil is also used to treat high blood pressure, although its exact mechanism of action on hair growth is still unclear. Finasteride is also used against benign hyperplasia of the prostate and is a synthetic 5-alpha-reductase inhibitor. However, use against hair loss is often accompanied by various side effects, such as itching due to eczema formation, increased heart rate, breathing difficulties, sudden weight gain, edema formation and skin inflammation or, in the case of finasteride, reduced libido, impotence and reduced ejaculate volume.

In the underlying study, the hair growth-promoting effects of a 3% minoxidil solution were compared with those of lavender oil.

Both the positive control group and both lavender oil groups showed a significant increase in hair follicles, a deepened hair follicle depth and a thicker dermal layer compared to the saline group over the course of the study.

In the fourth week of the study, in contrast to the saline solution group and the jojoba oil group, a clear hair growth-promoting effect was observed in both the lavender oil group and the control group. The number of degranulated perifollicular mast cells decreases significantly after the start of the anagen hair growth phase and increases significantly during the late anagen phase, immediately before the start of the catagen phase of hair growth. Catagen development is hindered by the inhibition of mast cell degranulation. Stressors induce the production of corticotropin-releasing hormones in the hair follicles, which in turn increases mast cell degranulation.

In the underlying study, the number of mast cells was significantly lower in the control group and both lavender oil groups than in the saline solution group and the vehicle group over the entire study period. It can therefore be concluded that lavender oil maintains the anagen phase of hair growth and delays the transition to the catagen phase.

Conclusion

The histological and morphological findings of the study results prove the clear hair growth-promoting effect of lavender oil.

Underlying study:

Lee, B. H. et al: Hair Growth-Promoting Effects of Lavender Oil in C57BL/6 Mice; in: Toxicological Research 2016 April; 32(2): 103-108.