Dear Editor,

Androgenetic alopecia is a significant problem for many patients, that affects their self-esteem and overall quality of life. At a time of high demand for therapies that counteract this most common type of alopecia, a new therapeutic option in the form of micro-dose injections of dutasteride directly into the scalp has appeared. Dutasteride is a second-generation inhibitor of the enzyme 5a-reductase, responsible for converting testosterone, the male sex hormone, into the more potent dihydrotestosterone, which contributes to the miniaturisation of hair follicles. Dutasteride lowers dihydrotestosterone concentrations by blocking type I and type II 5a-reductase enzymes, unlike finasteride, which only blocks type II enzyme [1–3].

Intralesional administration of micro-doses of duta­steride via mesotherapy into the hairy scalp is a new therapeutic method. It allows for a concentrated action of the drug directly in the follicular area with negligible systemic absorption [1]. Although dutasteride mesotherapy is not currently registered for the treatment of androgenetic alopecia there are reports supporting the efficacy of this form of therapy without systemic adverse effects [4–6]. However, an important problem in evaluating the aforementioned reports is that they cannot be adequately verified and confirmed by the results of extensive, placebo-controlled clinical trials.

The small number of studies that have been conducted to date on the efficacy of dutasteride mesotherapy is undoubtedly a major difficulty in assessing the benefit-risk balance of this method. The lack of unequivocal recommendations and standardisation of procedures has led to the problem that most of the studies performed, differ in metho­dology and the preparation or mixture of preparations used in the treatment. An analysis of the studies performed and their limitations is presented in Table 1.

The results of the above studies, although promising, do not allow for the creation of universal recommendations and have many limitations. Each of the studies conducted differed methodologically. The treatments differ in the number of injections repeated at different intervals. In addition, the mixture used in some of those studies often contained other substances in addition to dutasteride. Research conducted by Abdallah et al. [7] and Saceda-Corralo et al. [8] were conducted on a very small number of patients receiving dutasteride, amounting to 14 and 6 patients, respectively. Additionally, the Saceda-Corralo et al. study [8] was not placebo-controlled. In the studies conducted by Sobhy et al. [9] and Moftah et al. [10] patients were receiving injections not only with dutasteride but also with other substances such as dexpanthenol and biotin. Another study has evaluated other variables, such as the impact of metabolic syndrome on the effects of dutasteride mesotherapy treatment [4]. This makes it difficult to assess the isolated effect of dutasteride in the treatment of androgenetic alopecia. A study by Saceda-Corralo et al. [11] analysed reports from different research centres, whose methodology for conducting the study showed differences. Additionally, there are only a few reports analysing the side effects of dutasteride mesotherapy. Among the side effects described are two cases of paradoxical nonscarring alopecia [1] and angioedema-like contact dermatitis [12], which occurred after dutasteride mesotherapy. There are no publications more extensively analysing the safety and potential adverse effects of dutasteride mesotherapy, although most of the available studies analysing the therapeutic effect of this method did not report the occurrence of alarming adverse effects.

Despite promising reports on the efficacy of dutasteride mesotherapy in the treatment of androgenetic alopecia, there is a conspicuous lack of extensive placebo-controlled clinical trials on the efficacy and safety of this form of the­rapy. In our opinion, this is an important area for research that will help standardize the procedures performed on patients. This will increase the effectiveness of the therapy and ensure that patients are properly classified for treatment which can reduce the risk of adverse effects.

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Acknowledgements

The authors would like to thank all the academics who contributed to the knowledge they gained in the educational process.

Conflict of interest

The authors declare no conflict of interest.

Funding

None.