Your brain produces melatonin in response to darkness. It helps with the timing of your circadian rhythms (24-hour internal clock) and with sleep. Being exposed to light at night can block melatonin production. Melatonin can be taken as a supplement to help with sleep problems, such as insomnia or jet lag.
Your pineal gland releases the highest levels of melatonin when there’s darkness and it decreases melatonin production when you’re exposed to light. Thus, you have low levels of melatonin during the daylight hours and peak levels of melatonin during the nighttime.Melatonin has often been referred to as a “sleep hormone.” While melatonin isn’t essential for sleeping, you sleep better when you have higher levels of melatonin in your body. As your pineal gland receives information about the daily light-dark (day-night) cycle from the retina at the back of your eyes it releases melatonin accordingly. The longer the night, the longer your pineal gland secretes melatonin. People who suffer from blindness who can’t detect light often have irregularly synchronized melatonin cycles leading to circadian rhythm disorders.Research suggests that melatonin plays other important roles in the body beyond sleep. However, these effects are not fully understood.
https://my.clevelandclinic.org/health/articles/23411-melatonin
Hypomelatoninemia (low blood level of melatonin).Hypomelatoninemia happens when a person has a lower than normal total production level of melatonin when compared with what’s expected for their age or when you have lower-than-normal peak nighttime melatonin levels. Hypomelatoninemia can play a role in circadian rhythm sleep disorders, which are a group of sleep disorders that all share the common feature of a disruption in the timing of sleep.
Circadian rhythm sleep disorders have been classified as:
- Delayed sleep phase disorder: (delayed sleep-wake phase sleep disorder). In this disorder, your sleep pattern is delayed two hours or more from a conventional sleep pattern, causing you to go to sleep later and wake up later. Research shows that melatonin reduces the length of time needed to fall asleep and advances the start of sleep in adults and children with this condition. Talk to your child’s doctor before giving melatonin to a child.
- Insomnia. Research suggests that melatonin may reduce the time it takes to fall asleep, but its effects on sleep quality and total sleep time aren’t clear. Melatonin might be more beneficial for older adults who could be melatonin deficient. Slow release formulations of melatonin supplements may be more effective than those not prepared to obtain a slow release.
- Advanced sleep phase disorder: With this condition, you fall asleep in the early evening (6 p.m. to 9 p.m.) and wake up in the early morning (2 a.m. to 5 a.m.).
- Irregular sleep-wake rhythm: With this sleep disorder your sleep-wake cycle is not consistent. You likely take several naps during a 24-hour period.
- Non-24-hour sleep-wake syndrome: In this sleep disorder, your “internal clock” is longer than 24 hours. Your actual sleep-wake cycle changes every day, with the time being delayed one to two hours each day.
- Jet lag. Evidence shows that melatonin can improve jet lag symptoms, such as alertness and daytime sleepiness.
With these sleep disorders lack of sleep disrupts the quality of the sleep you do get, and that may contribute to the development of a number of health problems:
- High blood pressure (hypertension).
- Insulin resistance.
- Obesity.
- Metabolic syndrome.
- Increased risk of breast cancer and prostate cancer.
- Increased risk of Type 2 diabetes.
The causes of hypomelatoninemia are classified as primary or secondary. Primary causes are factors that cause damage to your pineal gland or a pineal gland tumor. Much more common are the secondary causes of hypomelatonemia.
Secondary causes of hypomelatoninemia are due to environmental factors and/or medications, including:
- Shift work.
- Aging – Melatonin production declines with age.
- Neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease.
- Beta-blockers. Calcium channel blockers. ACE inhibitors.
Of course, other factors contribute to your body’s ability to sleep and the quality of the sleep you get.
Taking melatonin as a dietary supplement may help with insomnia and certain conditions such as jet lag, delayed sleep-wake phase disorder, and anxiety before and after surgery.
How effective is melatonin for insomnia? With insomnia people have trouble falling asleep, staying asleep, or both. When the sleep disorder lasts a month or longer, it’s called chronic insomnia. According to practice guidelines from the American Academy of Sleep Medicine (2017) and the American College of Physicians (2016), there’s not enough strong evidence on the effectiveness or safety of melatonin supplementation for chronic insomnia to recommend its use. The American College of Physicians recommends the use of cognitive behavioral therapy for insomnia (CBT-I) as an initial treatment for insomnia. https://www.mayoclinic.org/drugs-supplements-melatonin/art-20363071
Researcher Dr. Luis Buenaver says, “Work with, not against, melatonin’s sleep-inducing signals. “Melatonin levels rise about two hours before bedtime,” “Create optimal conditions for it to do its job by keeping the lights low before bed. Stop using your computer, smartphone or tablet—the blue and green light from these devices can neutralize melatonin’s effects. If you watch television, be sure you’re at least six feet away from the screen. Turn off bright overhead lights too.”
You can try to help program your body to produce melatonin for sleep at the right time of day by getting exposure to daylight during the morning and afternoon.
https://www.hopkinsmedicine.org/health/wellness-and-prevention/melatonin-for-sleep-does-it-work
Does melatonin work for shift workers?
Night shifts may make it difficult to sleep during the daytime after a shift ends.
According to two 2014 research reviews, studies on whether melatonin supplements help shift workers were inconclusive.
There is some evidence that melatonin might control tumor growth in advanced cancer patients, through its function as a natural anti-angiogenic molecule as evidenced by decreased blood VEGF levels [61]. Studies of the effect of melatonin supplements on cancer symptoms or treatment-related side effects have been small and have had mixed results.
An NIH published article was called- Melatonin for the prevention and treatment of cancer
In the conclusion of this detailed comprehensive review article quoting many study references the authors say, “Numerous experimental studies have indicated an oncostatic role of melatonin in various cancers, such as breast, ovarian, prostate, oral, gastric, and colorectal cancers. The underlying mechanisms include several molecular pathways, which are associated with antioxidant activity, modulation of melatonin receptors MT1 and MT2, regulation of apoptosis, pro-survival signaling and tumor metabolism, inhibition of angiogenesis, invasion and metastasis, and induction of epigenetic alteration. Melatonin also showed the potential to be utilized as an adjuvant of cancer therapy through reinforcing the therapeutic effects and reducing the side effects of chemotherapies or radiation. In clinical trials, melatonin showed the ability to enhance the therapeutic effect of various anticancer drugs, and might help improve the sleep and life quality of cancer patients. Overall, the impressive efficacy and safety of melatonin support it as a promising agent for the prevention and treatment of cancers.”
Unproven cancer remedies products should not be used to replace or delay conventional medical treatment for cancer. People who’ve been diagnosed with cancer should talk with their health care providers to make sure that all aspects of their care work together.
Biological Mechanism of Melatonin
An NIH published review artcile outlines melatonin,is possible actions on a number of body systems.
https://www.ncbi.nlm.nih.gov/books/NBK534823/
Bone deposition: An effect on osteoblasts suggest melatonin’s involvement in regulating their function.
Metabolic disorders: Melatonin has antioxidative and anti-inflammatory effects and regulates lipid and glucose metabolism.
Cardiovascular diseases: Melatonin has demonstrated anti-hypertensive effects.
Gastrointestinal conditions: Due to Melatonin’s antioxidative and anti-inflammatory effects.
Neurodegenerative disorders: Melatonin may activate mitochondrial cell survival pathways, thus safeguarding against neurodegeneration induced by mitochondrial dysfunction.
Mental disorders: Melatonin is approved for treating depression in Europe. It is also used as an antianxiety drug.
Pain syndromes: Melatonin has anti-nociceptive, analgesic effect and anti-inflammatory effects.
Cancer suppression: Activating tumor suppressor genes, immunomodulation, and increasing cytokine production, collectively may contribute to cancer suppression.
Reproductive functions: Melatonin is involved pathways that reduce the risk of pregnancy complications, promoting higher rates of mature oocytes and quality embryos.[20][21][22]
