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 (N–tert-Butyl-3-oxo-4-aza-5α-androst-1-en-17β-carbamid) 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 2% minoxidil solution were compared with those of a rosemary oil solution.
Due to its soothing effects against eczema, acne, skin swelling and dermatitis, rosemary, which has been valued for its healing powers for centuries, is often used in the form of rosemary oil as an ingredient in active ingredient cosmetics. It is assumed that the antispasmodic effect of rosemary increases microcapillary perfusion. It has therefore been hypothesized in research that rosemary oil increases the blood supply to the hair follicle and can therefore be used effectively as an active ingredient in the treatment of hereditary hair loss (AGA). The underlying study examines the spectrum of action and efficacy of rosemary oil in the treatment of hereditary hair loss and compares it with the effects of a 2% minoxidil solution.
The study was conducted over a period of 6 months as a single-blind, randomized, clinical trial. The participants were men between the ages of 18 and 49 who suffered from congenital hair loss. The study participants applied 1 ml of their assigned solution (rosemary oil solution or 2% minoxidil solution) twice a day at twelve-hour intervals. The respective solution was lightly massaged into the frontoparietal area of the scalp and the parting area over a period of 6 months according to the above-mentioned scheme. After an initial examination at the beginning of the study, the participants were examined every 3 months to determine the effect and tolerability of the solutions used.
The resulting data was analyzed by software using the so-called t-test and the chi-square test for the analysis of variance, the Bonferroni method was carried out.
After 6 months, there was a significant increase in the number of hairs in both the rosemary oil group and the 2% minoxidil group. There was no significant difference between the two groups after 6 months. This shows that the hair growth-promoting effect of rosemary oil and the 2% minoxidil solution was similarly strong. However, participants in the minoxidil group reported more frequently that scalp itching occurred as a side effect of using the 2% minoxidil solution.
The study participants were also given a questionnaire, the answers to which specified two aspects of hair growth and hair loss during the course of the study. In their answers, the participants indicated, among other things, their personal assessment of the increase in hair growth and the decrease in hair loss using selectable categories (mild, moderate, no difference, worse than before). This data showed that the rosemary oil group rated their experience better than the minoxidil group. Hair loss was reduced in both groups, with the rosemary oil group showing significantly better results in the interim examinations and surveys after 3 and 6 months respectively, i.e. the use of rosemary oil correlated with less hair loss.
Conclusion
The hypothesis tested by the authors that rosemary oil promotes hair growth proved to be correct based on the study results. The hair growth-promoting effect is attributed by the study authors to several properties of rosemary oil: firstly, the dilation of the scalp blood vessels caused by the antispasmodic effect and the resulting increased blood flow to the hair follicles, and secondly, the antioxidant effect of rosemary oil. Scientific research results show a clear link between oxidative stress and hair loss. In patients with hair loss symptoms, lower levels of antioxidants and increased levels of oxidants were detected. The antioxidant activity of rosemary oil is scientifically well documented. Rosemary oil binds so-called free radicals and suppresses lipid peroxidation. In addition to its potentiating effects on microcapillary blood circulation, rosemary oil has various other well-documented pleiotropic properties, such as its antibacterial and antifungal effects. Rosemary oil also nourishes and strengthens the skin, leaving hair silky and soft to the touch.
In the underlying study, rosemary oil proved to be just as effective against hair loss as a 2% minoxidil solution. In addition, the study participants in each group accepted the rosemary solution better than the 2% minoxidil solution, which can be attributed to the reduced scalp itching and hair loss in the rosemary oil group.
In the study, rosemary oil clearly proved to be an effective and well-tolerated remedy for congenital hair loss.
Underlying study:
Panahi, Y. et al: Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial; in: SKINmed 2015 January-February; 13(1):15-21.