Melatonin increases

Melatonin, an endogenous substance secreted by the pineal gland, is a regulating hormone that almost directly or indirectly affects the secretion of all other hormones. It has a wide range of physiological activities, can enhance the function of the immune system, and regulate the endocrine system. It has anti-oxidant effect, protects cells from free radical damage, can delay aging and prolong life, but increased secretion of melatonin may cause seasonal depression.