The objective of this study is to find out the effect of yeast on hair loss treatment and the role of hair follicle stem cell activator, which is important in hair growth. The authors have recently produced a substance, which has no disgusting odor, does not precipitates and does not easily corrupt, to use instead of yeast acquired from raw rice wine(Makgeolli). The substance is named Yeast Constituent Extract(YCE). In this research, the Produced YCE was applied on the hair loss area of 10 Androgenic alopecia patients, twice every day for 6 months, in order to test the effect of hair loss treatment and the role of stem cell activator. As a result, all of the patients showed a significant growth of hair after 3 months of test, and showed much more growing, thickening and strengthening of hair after 6 months. As a result of measuring the number of hair strings in the same scalp region of the patients after 6 months, it is found that the density of hair has increased, indicating that the hair loss treatment was effective. Also the hair follicle stem cell was isolated from the patients and the contents of growth factors (IGF, VEGF, FGF, HGF) derived from hair follicle stem cell were measured with ELISA. As result, the amount is found to be about 10 times greater than before the test. The hair follicle stem cell contains many growth factors that affect growth of hair, so it takes a highly important role in hair loss treatment. The YCE that the authors have produced was found to be effective in increasing the contents of growth factors that are derived from hair follicle stem cell. Thus it can be inferred that the YCE plays a role as a stem cell activator that activates the hair follicle stem cells. In conclusion, the YCE is considered to be highly effective for hair loss treatment and to have a role as a stem cell activator.