THE SYSTEMATIC REVIEW OF VARIOUS HERBS SHOWS HAIR GROWTH-PROMOTING ACTIVITY AND THEIR POSSIBLE MECHANISM OF ACTION AS AN ALTERNATIVE TREATMENT FOR ALOPECIA.
The term alopecia is defined as a loss of hair from the scalp, or any other part of the body and it comes in two major groups: non-scarring and scarring alopecia. The most common type of non-scarring alopecia is Androgenetic alopecia (AGA), followed by Alopecia areata (AA). As approved by the US FDA, the readily available treatment for AGA is now the usage of synthetic drugs such as Finasteride and Minoxidil, while for AA immunosuppressives. Due to their lack of staple efficacy and worrisome side effects, researchers are leaning on herbal-based natural products and isolated compounds as a safer and more potent alternative. Some of these products have been shown to possess hair growth activities, but the mechanism responsible for the activity is not discussed. This literature review aims to perform a critical analysis of the studies’results and study model to suggest the potential underlying mechanism. This literature review was carried out by journal screening on databases such as Google Scholar and PubMed using specific keywords and inclusion criteria, obtaining a total of 43 articles, of which 36 were further analyzed. Afterward, analyses of their study model, taxonomy, and toxicity were done to determine the quality of these studies. The study used were mainly C57BL/6 mice, while In vitro, human dermal papilla cells were used. The studies also showed a lack of specificity in alopecia type, inappropriate taxonomy usage and the lack of sufficient information regarding their toxicity. It was found that most of the herbs and compounds affect hair growth by regulating from the hair growth cycle. They work by inducing the transition of telogen to anagen, prolonging the anagen phase and preventing its phase ending to induce the catagen phase. To conclude, this literature review has compiled and elucidated the possible mechanism behind their hair growth-promoting activities related to alopecia and discussed the quality of the studies. However, the specificity of the alopecia type, quality of the taxonomy and toxicity needs improvement to provide better-quality evidence that ensures the efficacy and safety of the herbs and compounds.