Phase I Clinical Study to Assess Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single and Multiple Doses of LYN101

Inclusion criteria

Inclusion Criteria for Part A: 1. Fully understand the purpose and requirements of the trial, voluntarily participate in the clinical study, and sign a written informed consent form. 2. Individuals aged 18 to 65 years (inclusive), regardless of gender; 3. Weight ≥ 50 kg for males or at least 45 kg for females, with a Body Mass Index (BMI) ranging from 18.0 to 30.0 kg/m² (inclusive). 4. Males and females of childbearing potential agree not to plan for childbearing and to use reliable contraceptive measures from the time of signing the written informed consent until 6 months after dosing. They also agree not to donate sperm or ova. Inclusion Criteria for Part B: 1. Fully understand the purpose and requirements of the trial, voluntarily participate in the clinical trial, and sign a written informed consent form. 2. Individuals aged 50-70 years (inclusive), female, and ambulatory. 3. Spontaneous amenorrhea lasting for at least two years or bilateral oophorectomy performed at least two years prior. For women under 60 years of age who have undergone hysterectomy but retained their ovaries, or when the status of bilateral oophorectomy is unknown, menopausal status must be confirmed by follicle-stimulating hormone (FSH) levels exceeding 40 mIU/mL or in accordance with the postmenopausal range established by the local laboratory. 4. During the screening process, at least two consecutive vertebrae within the L1-L4 region must be evaluable for DXA BMD assessment, and at least one hip must also be evaluable for DXA BMD assessment. 5. Low bone mass, as measured by Dual Energy X-ray Absorptiometry (DXA) during screening (BMD), shall meet the criteria if any site has a T-score less than -1.0 and greater than -2.5 at the lumbar spine L1-L4, femoral neck, or total hip.