To provide a method for increasing growth hormone secretion in a patient, useful for preserving muscle mass or muscle force produced by physical exercise, and satisfying a keen desire for developing an alternative to conventional methods where an anabolic steroid is used for increasing the muscle mass and enhancing physical power, because users of the anabolic steroid suffer from adverse effects.

This method for increasing the growth hormone secretion in the patient comprises stimulating the patient through physical exercise, wherein the method includes administering the growth hormone secernent in a therapeutically effective amount to the patient. Further, the method for promoting to improve the muscle mass or the muscle force of the patient is provided by using the growth hormone secernent on combination with the physical exercise. The growth hormone secernent preferably comprises a compound of the formula I, its prodrug, and a pharmaceutically acceptable salt of the compound and the prodrug.