Melatonin is a hormone naturally derived from the amino acid tryptophan and the neurotransmitter serotonin. It is produced naturally in the pineal gland, but other organs, such as the stomach, also produce smaller amounts. Melatonin is essential for maintaining the body's circadian rhythm, so that you feel alert and energetic in the morning and sleepy in the evening. This is why melatonin levels in the blood are higher at night and decrease significantly in the morning.

But melatonin does more than that. It is also essential for proper immune system function, eye function, reducing oxidative stress, controlling cell function, preventing cell atrophy, and strengthening brain function, to name a few.

Melatonin levels naturally decrease with age, which is why it becomes more difficult to fall asleep and get a good night's rest after the age of 60. Some studies have shown that melatonin can also be used in the prevention and treatment of certain cancers, such as breast, prostate, and colorectal cancer.