Melatonin is a natural hormone produced by the pineal gland inside your brain. It is generally secreted at night times and the highest levels are measured between 11:00 pm to 07:00 am. Darkness promotes the production of melatonin, the darker your bedroom is the more melatonin is produced in your body. There are many functions of melatonin but its major function is to regulate and maintain the sleep-wake cycles (circadian rhythm) in your body.
Melatonin Synthesis and Circadian Photoentrainment
The biosynthesis of melatonin starts from the dietary protein which is found in the foods we consume. This dietary protein contains a very important essential amino acid tryptophan, which in the presence of enzymes gets converted to serotonin first and subsequently into melatonin.
A photopigment receptor protein, melanopsin is found in the photosensitive retinal ganglion cells of the eye. When this melanopsin is exposed to light, it responds and communicates information or transmit signals to an area in the brain called suprachiasmatic nucleus – SCN ( a biological clock that houses the circadian pacemaker).
So a light-induced activation of the SCN prevents the pineal gland from producing melatonin and keeps you awake. Similarly, darkness-induced activation of the SCN stimulates the pineal gland for the secretion of melatonin which helps you to fall asleep. This process of synchronization between the internal body’s clock and the external cycle of light-darkness is known as circadian photoentrainment.
Melatonin Deficiency Symptoms
Low levels of melatonin are due to over exposure to light. Here are the few symptoms
- Excessive fatigue
- Night eating syndrome
- High blood pressure
- Sensitivity to stress
- Neurodegenerative disorders
Synthetic Melatonin (Supplement)
A synthetic version of melatonin is also available as a supplement in the market. Synthetic melatonin is used to adjust the body’s internal clock. It is generally available in the pill form and it is used to treat jet lag, shift-work disorder, delayed sleep phase syndrome and Insomnia. The recommended dosage is 0.3mg – 5mg melatonin before bed. Some of the brands include Natrol, Puritan’s Pride, and NatureMade. Long term usage of melatonin is usually not recommended as it has a lot of side effects.
Side Effects of Synthetic Melatonin
- Daytime drowsiness.
- Depressed mood.
- Stomach pain
- Decreased sperm count in men
- Decreased sex drive
Try to get melatonin naturally by eating tryptophan-rich foods which include nuts, tofu, fish, oats, eggs, beans and lentils.