In all mammals, including humans, melatonin is secreted during darkness by the pineal gland, which lies within the brain. Because of the requirement for darkness, the body's ability to produce melatonin is greatly reduced when regularly sleeping in a room that is not completely dark (such as with a night light), or when sleeping during the day without blackout curtains . The body's ability to create melatonin also decreases with age. Melatonin has been on the market for several decades as a natural sleep aid. However, ongoing research has revealed that it has many health applications besides alleviating insomnia. The list below is compiled from that research and presented only as information about this product. It is not intended as medical advice. In 1993, scientists discovered that melatonin exerts a powerful antioxidant activity in the body, stronger even than Vitamin C. Antioxidants counteract free radicals in the body, which are atoms within cells that lose an electron. An atom with an unpaired electron will reach out and grab a replacement electron from another atom nearby. If this process becomes widespread and unchecked in the body, it can lead to extensive biological damage at the cellular level. Melatonin has also been demonstrated to prevent DNA damage by carcinogens, and its antioxidant activity may reduce the effects of some types of Parkinson's disease. It has been found helpful in preventing cardiac arrhythmia. It supports the immune system and may be a helpful adjunct to treatments for autoimmune disorders of all kinds. Some research has indicated that it might help fight both viral and bacterial infections and potentially treat cancer. Researchers have theorized that reduced melatonin production in the body may be a contributor to the documented, significantly-higher cancer levels in night workers. Low melatonin levels have been found to be associated with learning problems, especially memory disorders, including Alzheimer's. Researchers in Italy discovered that evening melatonin supplementation in perimenopausal women improved their thyroid function and reduced depression sometimes associated with the lowering of progesterone and estrogen levels in the body with the onset of Menopause. Clinical studies have indicated that melatonin may prevent migraines and cluster headaches, and it has been used as a treatment for seasonal affective disorder (SAD). Studies have also shown melatonin to have a protective effect against the ravages of radioactive fallout. People who suffer from irritable bowel syndrome (IBS) have found relief with melatonin. And last but not least, veterinarians often recommend melatonin for dogs suffering from aggression or anxiety, including fear of thunderstorms. There is no one-size-fits-all dosage for melatonin. Most healthcare experts recommend "titrating" the dosage. That is, start out small and work up until the desired effect is achieved, in particular as a sleep aid. Some people receive relief from insomnia taking as little as 1 mg. per day. Others need up to 5 mg., the dosage in this particular version of melatonin. Melatonin also comes in both pills that you swallow and sublinguals, such as this product, which are dissolved beneath the tongue. A sublingual allows the melatonin to be introduced directly into the blood by absorption through the blood vessels under the tongue, rather than having to pass through the stomach and digestive system. This means that more of the supplement gets into your system, and it gets there faster. There are dozens and dozens of producers of melatonin on the market. I personally chose this one because Source Naturals has a very good reputation for the purity of their supplements and for outside laboratory confirmation that each supplement contains what is listed on the label. The flavor of these tablets are a pleasant orange. I've taken melatonin for many years as a sleep aid, and I've been delighted to hear as research continues to be done on this supplement that not only is it safe, but it is healing and protective on multiple levels within the body. I also have spent many years of my life as a night worker, and it is good to know that night workers can make up for the damage that this can cause to the body, including (as mentioned above) a higher-than-normal tendency to get cancer