What are the side effects of melatonin?
Mar 19, 2025
Source: Cainiu Health
Dr. Yang Ziqi
Introduction
In general, possible side effects of melatonin may include drowsiness, headache, nausea and vomiting, sleep disturbances, and hormonal imbalances. If you plan to take melatonin, it is recommended to start with a small dose and observe your body's response. At the same time, pay attention to any adverse symptoms such as allergic reactions. If any abnormalities occur, discontinue use immediately and seek medical attention promptly.
Generally, the side effects of melatonin may include drowsiness, headache, nausea and vomiting, sleep disturbances, and endocrine disorders. It is recommended to use this medication according to medical advice. Detailed analysis is as follows:
1. Drowsiness
Melatonin regulates the body's sleep-wake cycle. After administration, it enhances sleepiness. If taken at an inappropriate time or in excessive dosage, it may cause significant daytime drowsiness. Additionally, it may affect cerebral blood circulation or the balance of neurotransmitters, potentially leading to dizziness.
2. Headache
Melatonin may affect the constriction and dilation functions of cerebral blood vessels, causing vascular spasms or abnormal dilation, thereby inducing headaches. This could also be related to its regulatory effects on the nervous system. Disruption of the nervous system's normal rhythm may impact the patient's mood and quality of life.
3. Nausea and Vomiting
Melatonin may irritate the gastrointestinal mucosa, affecting normal gastrointestinal motility and digestive functions, leading to gastrointestinal dysfunction and causing symptoms such as nausea and vomiting, which may affect appetite and nutrient intake.
4. Sleep Disturbances
Although melatonin helps induce sleep, excessive or inappropriate use may interfere with the normal structure of sleep, affecting the regular alternation between rapid eye movement (REM) and non-rapid eye movement (NREM) sleep phases. This may lead to increased nightmares or more disordered sleep.
5. Endocrine Disorders
Long-term and excessive use of melatonin may suppress the normal secretion function of the pineal gland, resulting in disturbances in the body's melatonin secretion regulation mechanism. Additionally, it may affect the function of other endocrine glands, disrupting hormonal balance. Women may experience menstrual cycle irregularities and abnormal menstrual flow; men may encounter reduced sexual function. It may also lead to thyroid dysfunction and blood glucose fluctuations, affecting normal metabolic and physiological functions.
If you plan to take melatonin, it is recommended to start with a low dose and observe your body's response. Additionally, pay attention to any adverse symptoms such as allergic reactions. If abnormalities occur, stop taking the medication immediately and seek medical attention promptly.
