Low creatinine, i.e. low serum creatinine, is one of the important indicators to evaluate kidney function. Usually, there are differences in the standard values of whole blood creatinine, with the average value of 53-106 μmol/L for men and 44.2-88.4 μmol/L for women. If there are no obvious symptoms of physical discomfort, this low value is usually not clinically significant, and it is recommended to review the creatinine value regularly. If the patient also has other abnormal test values or physical discomfort, it may be related to a variety of disease factors. Low creatinine is usually associated with older age, excessive leanness, low protein intake due to malnutrition, etc. It may also be associated with changes in hormone levels during pregnancy and an increase in the glomerular filtration rate of women, resulting in increased excretion of creatinine. Creatinine is the waste product produced by the metabolism of protein in the body. Therefore, the above-mentioned people may have low creatinine. If the body does not show any uncomfortable symptoms and the other test values are in the normal range, no special treatment is usually needed and daily attention to protein supplementation is sufficient. In addition, low creatinine may be associated with early diabetes, anemia, muscle atrophy, hyperthyroidism, renal insufficiency, liver dysfunction, leukemia, uremia, and other diseases. However, it is usually not possible to make a definite diagnosis by only one indicator of low creatinine, and it is necessary to make a comprehensive judgment based on other examination results and one’s own symptoms after completing relevant examinations.