Abstract: Embodiments herein are directed to methods for increasing testosterone levels in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of testosterone by needle-free injection to an injection site. Some embodiments are further directed to a method of increasing testosterone levels in a subject in need thereof, by administering to the subject a pharmaceutical composition comprising a therapeutically effective amount of testosterone and a pharmaceutically acceptable carrier by needle-free injection. Some embodiments are directed to a method of minimizing fluctuations in testosterone levels in a subject diagnosed with hypogonadism, comprising serially administering to the subject a therapeutically effective amount of testosterone by needle-free injection to an injection site.