The treatment of androgenetic alopecia (AGA) is usually long lasting, and the effects of treatment attempts are difficult to measure. Consequently, there was a need for a sensitive tool to monitor hair loss and treatment response. Therefore, we developed the Trichoscan as a method which combines epiluminescence microscopy with automatic digital image analysis for the measurement of human hair. The Trichoscan is able to analyze all important parameters of hair growth (density, diameter, growth rate, vellus and terminal hair density) with an intraclass correlation of approximately 91% within the same Trichoscan operator and an intraclass correlation of approximately 97% for different Trichoscan operators. The application of the technique was demonstrated by comparison of the hair parameters in 9 men with frontal balding which were treated for 6 months with 5% minoxidil. Even in this small cohort of patients, we noticed after 3 months of treatment compared to baseline a significant increase in hair density (+21.3 hairs/cm2; p = 0.047) and cumulative hair thickness (+0.61 mm; p = 0.008) and after 6 months a significant increase in hair density (+34 hairs/cm2; p = 0.011) and cumulative hair thickness (+0.88 mm; p = 0.010). The study shows that the Trichoscan has many advantages. It can be used for clinical studies to compare placebo versus treatment or to compare the relative potencies of different hair-growth-promoting substances. It can be used for studying AGA or other forms of diffuse hair loss, and it can be adopted to study the effect of drugs or laser treatment on hypertrichosis or hirsutism. The drawbacks, however, are that the Trichoscan still needs a hair dye for contrast enhancement and the measurement area must be clipped before analysis. This mini-review summarizes recent attempts to optimize the technique and shows new options such as the calculation of follicular units or the 'anagen hair count'.