This is a multiple-dose, dose-escalation, randomized, double-blind, placebo-controlled phase Ⅱa clinical trial. A total of 36 adult participants with growth hormone deficiency will be enrolled sequentially in ascending dose cohorts, and within each dose cohort, participants will be randomized in a 3:1 ratio.

Inclusion Criteria:

• Male study participants aged ≥ 18 years and < 80 years at the time of signing the informed consent form (ICF);
• Study participants meeting the criteria for adult growth hormone deficiency (AGHD):

Patients with a peak GH level < 5 μg/L measured by insulin tolerance test (ITT); OR Patients with an IGF-1 level below -2.0 SDS for age and sex at screening (see Appendix 4);

• No systemic treatment with growth hormone or growth hormone secretagogues within 6 months prior to entering the screening period;
• For patients with any other pituitary hormone deficiency who are on hormone replacement therapy (HRT) at screening, HRT must have been stable for at least 3 months;
• Study participants must agree to use reliable contraceptive measures with their spouses from - Study participants fully understand the purpose, nature, methods and potential adverse reactions of the trial, voluntarily participate in the study, and have signed the informed consent form.

Exclusion Criteria:

• Individuals with known or suspected hypersensitivity to the investigational product or its excipients;

• Patients with severe malnutrition as judged by the investigator, or with a BMI < 18.5 kg/m² at screening;

• Patients with active malignancy or a history of malignancy; or with thyroid nodules classified as TI-RADS grade ≥ 4a on thyroid ultrasound; or with high-risk or suspected malignant nodules detected on chest CT; or with clinically significant abnormal tumor markers at screening;

• For patients with a history of pituitary adenoma or other benign intracranial tumors:

  1. Surgical resection of pituitary adenoma or other benign intracranial tumors within 12 months prior to screening;
  2. Evidence of growth of pituitary adenoma or other benign intracranial tumors within 12 months prior to screening (must be confirmed by two postoperative MRI scans, with the most recent MRI scan performed ≤ 6 months before the screening period);

• Patients with abnormal liver or renal function at screening (ALT > 3×ULN, Cr > 1.5×ULN);

• Patients testing positive for hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (anti-HCV), or human immunodeficiency virus antibody (anti-HIV) at screening;

• Patients with a clinically significant change in body weight within 6 months prior to screening as judged by the investigator, or with a self-reported body weight change of ≥ 10% compared to 6 months before screening;

• Patients with unstable control of diabetes mellitus within 3 months prior to screening (HbA1c ≥ 7.5% at screening), or with significant adjustment of hypoglycemic medication dose or change in therapeutic drug type, or with severe diabetic complications as judged by the investigator;

• Patients with cardiac insufficiency classified as NYHA class ≥ III;

• Patients with a history of acromegaly or gigantism;

• Patients with mental disability or language impairment that prevents full participation in the trial;

• Individuals who have participated in any clinical trial of investigational medicinal products (as a trial participant) and received investigational intervention within 3 months prior to screening;

• Other conditions deemed unsuitable for enrollment by the investigator.