Evaluate the Effect of Dietary Supplement on Muscle Mass and Physical Performance for Over 50 Years Old People

Main Inclusion Criteria: 1. Male or female aged 50 years or older. 2. Subjects who has muscle loss or at risk of muscle loss, with symptoms of reduced physical activities, reduced gait speed, exhaustion, or had tumbled/ fallen within past year 3. Willing to comply with study procedures and follow-ups 4. Provide written consent Main Exclusion Criteria: 1. Gait speed ≤ 0.3 m/sec 2. Any disease that interferes with limb function, including: 1. Limb fracture within past 6 months 2. Severe knee, hip, or arm arthritis 3. As judged by the investigator, disorder of nervous system (i.e., stroke, severe spinal stenosis, peripheral neuropathy, and Parkinson's disease) with poor control 4. Intermittent claudication due to peripheral artery disease 3. As judged by the investigator, mental disorders (i.e., confirmed diagnosis of dementia) with poor control 4. Cardiopulmonary disease with poor control judged by the investigator 5. Malignancy with poor control judged by the investigator 6. Subjects claim to have chronic renal disease, defined as kidney damage or GFR \< 30 mL/min/1.73 m2 for at least 3 months 7. Severe visual and hearing impairment that becomes barrier to communication 8. Subjects have taken any hormone replacement therapy within 3 months prior to study enrollment, or plans to begin hormone replacement therapy at any time during the study 9. Subjects with known poorly controlled diabetes (HbA1c \> 9.0%), hyperthyroidism or thyroid insufficiency, Cushing's syndrome, or adrenal insufficiency 10. Subjects with known milk allergy or lactose intolerance 11. Other conditions that investigator considers subject is ineligible to participate in the study