The present invention relates to compositions and methods for the preventing, treating, and researching discoloration (e.g., hair graying, hair whitening, undesired change in hair color). In particular, the present invention provides compositions and methods for treating, preventing and researching hair discoloration through inhibition of mTOR function (e.g., mTOR activity, mTOR expression). In addition, the present invention provides methods and compositions that utilize mTOR inhibiting agents in the preventing, treating, and researching hair discoloration.