Provided are a composition for preventing hair loss and stimulating hair growth, which includes small-sized stem cells, particularly, small-sized stem cells having a diameter of 8 µm or less, or a conditioned medium thereof as an active ingredient, a method of preparing the same, and a use of the same. Provided is a use of the composition utilizing a hair growth stimulating function of the small-sized stem cells having a diameter of 8 µm or less to considerably increase activity of hair follicle stem cells in a telogen phase.
