Provided are: a method for adjusting the optimal blend amount of 6-benzylaminopurine at which the hair growth effect of 6-benzylaminopurine can be exhibited； and a hair growth agent composition produced by the method. The present invention provides: a method for preparing a solution using a mixed solvent of water and ethanol in which the solvent ratio of water to ethanol is 65:35 to 10:90 (by weight) relative to an effective concentration of 0.2 to 1.0 wt% of 6-benzylaminopurine； and a hair growth agent composition prepared using a solution produced by the method. The hair growth agent composition can be used particularly as a hair tonic.本發明係提供一種調製可發揮6-苄胺嘌呤(6-benzylaminopurine)育毛效果之最適當摻混量之方法，及利用該方法所得之育毛劑組成物。根據本發明，可提供對於6-苄胺嘌呤有效濃度之0.2~1.0重量%，使用水與乙醇之溶媒比(重量比)為65：35~10：90之混合溶媒，調製溶液之方法，及使用利用該方法所得溶液之育毛劑組成物。相關的育毛劑組成物特別可使用為護髮素。
