Efficacy and Safety of Kefir Whey Postbiotics

Inclusion Criteria: 1. Adult men and women aged 40 years or older at the time of screening test 2. Adult men and women with a Charlson Comorbidity Index (CCI) score of 0 at the time of screening 3. Adult men and women with skeletal muscle mass less than 110% of the standard as measured by BIA (bioelectrical impedence analysis) at the time of screening test Exclusion Criteria: 1. Those with significant hypersensitivity to melon gourd, whey, or lactic acid bacteria ingredients 2. Those who participated in other human application tests, diet, or exercise programs within 3 months before the screening test 3. Persons with clinically significant acute or chronic cardiovascular, diabetes, endocrine, immune, respiratory, hepatobiliary, renal and urinary, neuropsychiatric, or gastrointestinal diseases requiring treatment. 4. Those who show the following results in blood or urine tests: * AST, ALT \> 1.5 times the upper limit of the reference range * Serum Creatinine \> 1.4 mg/dL * Fasting blood sugar \> 126mg/dL 5. If there is 2+ or more proteinuria 6. Persons taking medication for psychiatric illness (excluding cases of intermittent medication due to sleep disorders) 7. Those who consumed pro- or prebiotics within 1 month before the screening test 8. Those who have taken protein supplements regularly for more than 3 months within 6 months before the screening test 9. Those who received other investigational drugs within 1 month before the screening test 10. Those who received antibiotics within 2 months before the screening test 11. Those who are currently controlling their diet for disease management purposes 12. Those with a history of gastrointestinal resection (excluding the appendix) 13. Those who are performing or plan to perform regular resistance exercise 14. People with vegetarian beliefs 15. People with food allergies or restricted foods 16. Persons with a history of diagnosed gastrointestinal disease (ex. ulcerative colitis, Crohn's disease, gastroparesis, peptic ulcer disease, cancer, celiac disease, short bowel, and ileostomy) 17. Those taking constipation or diarrhea medication 18. Those who currently smoke 19. Those whose BMI exceeds 30kg/m2 at the time of screening test 20. Those who plan to control their weight within 6 months after screening 21. Those who are likely to be uncooperative in this test or those who are determined by the researcher to be unable to proceed with the test