Low creatine kinase may be caused by prolonged bed rest, hyperthyroidism, hormone therapy, low basal value of the organism itself, etc. It is usually harmless. 1. Prolonged bed rest: If you lie in bed for a long time, your muscles will be at rest and you don’t get enough exercise, creatine kinase will be low. 2. Hyperthyroidism: usually a generalized metabolic syndrome caused by excess thyroxine. Excessive secretion of thyroid hormone causes a toxic reaction of the thyroid gland, leading to accelerated metabolism and endocrine disorders, which may also lead to low creatine kinase. 3. Hormone therapy: taking contraceptives such as levonorgestrel tablets can reduce the activity of creatine kinase, leading to low creatine kinase. 4. Low basal value of the body itself: due to the different physique of each person, some patients may have low basal value of the body itself. Generally low creatine kinase is harmless. Normal creatine kinase value is 18 to 198 units/liter. Creatine kinase is an important substance and enzyme in skeletal muscle, cardiac muscle and smooth muscle. It is clinically important only when it is increased, and generally low levels are meaningless. It is recommended to consult a doctor in time for relevant examination, and according to the specific situation, symptomatic treatment under the guidance of the doctor.