## 5 Discussion  
### Efficacy of Conventional Therapies for Hair Loss Compared to Complex Nutritional Supplementation  
In the present review, only complex dietary supplements were considered with regard to hair growth. However, the conventional therapies available are minoralid and finasteride, as well as the autologous regenerative therapies based on platelet-rich plasma and stem cells such as adipose-derived mesenchymal stem cells and human hair follicle epithelial stem cells [45]. Finasteride(r) is an oral drug for the treatment of androgenetic alopecia by inhibiting the formation of dihydrotestosterone as a 5-alpha reductase inhibitor. [PERSON] et al. show that, in a study of 212 men with AGA taking 1 mg Finasteride(r) daily for 48 weeks, there was a significant improvement of 17 total hairs (8%) and 27 anagen hairs (26%) compared to the placebo group [46].  
Minoxidil is available as a 5% solution or 5% foam for men and 2% solution for women and is used topically. It extends the anagen period and increases hair follicles by activating prostaglandin-endoperoxide synthase-1. For minoralid 5% it was shown that the hair density had improved by about 19 hairs/cm\({}^{2}\) with topical application and by about 38 hairs/cm\({}^{2}\) with electrodynamics micro-needle treatment plus topical minoxidil 5% after 24 weeks compared to baseline [47].  
In a systematic review by [PERSON] et al., the superiority and effectiveness of these treatments in men with AGA as well as minoralid in women with AGA compared to placebo was shown by five meta-analyses [48].  
An alternative therapy to improve hair loss is autologous activated platelet-rich plasma (PRP). It is believed that the positive effect on hair growth is mainly an anti-apoptotic effect through activation of the Bcl-2 protein and Akt signaling. In detail, it was shown that hair density improved by 28 hairs/cm\({}^{2}\) compared to placebo [49].  
In a systematic review by [PERSON] and [PERSON], 12 clinical studies regarding PRP were analyzed, with the result that 84% of the study showed a positive effect as AGA treatment. 50% of the studies even showed statistically significant effects, while 34% of the studies showed an improvement in hair density and thickness. Based on these data and no major side effects, this treatment is being considered as an alternative to the above mentioned conventional therapies [50].  
As a further autologous therapy, a microgrid with human hair follicle mesenchymal stem cells showed an improvement in hair density of 23 hairs/cm\({}^{2}\) compared to the baseline and to the placebo group. After only six months, the patients showed hair loss again [51].  
Hair re-growth was also obtained by micro-graft from scalp tissue containing \"Human intra and Extra Dermal Adipose Tissue-Derived Hair Follicle Stem Cells (HD-AFCS)\". These, in turn, consist of approximately 6% hair follicle mesenchymal stem cells and approximately 3% hair follicle epithelia stem cells. After three injections in an interval of 45 days, test subjects showed, after half a year and up to one year after the last injections, an improvement in hair density of 33% and 27%, respectively. Only three treated patients showed a relapse of hair loss in the following 16 months [52].  
However, the present review shows that hair growth can also be improved by nutritional supplementation even though the publications are very sparse with statements on anagen and telogen rate. For example, a 20% increase in the anagen rate could be achieved by taking the product Biogenina(r) [42] and the hair density was improved by 12 hairs/cm\({}^{2}\) using Viviscal(r) Man [40].