Circadian rhythms are 24-hour cycles that are part of the body’s internal clock, running in the background to carry out essential functions and processes. One of the most important and well-known circadian rhythms is the sleep-wake cycle. 
The cells in our brain respond to light and dark. When our eyes capture such changes in the environment, they send signals to different cells about when it’s time to be sleepy or awake.
Those cells then send more signals to other parts of the brain that activate other functions that make us more tired or alert. Natural factors in our body produce circadian rhythms. For humans, some of the most important genes in this process are the Period and Cryptochrome genes.
Body temperature and metabolism are also part of our circadian rhythm. Our temperature drops when we sleep and rises during awake hours. Additionally, our metabolism works at different rates throughout the day. Age is another factor that influences our circadian rhythm. Infants, teens, and adults all experience circadian rhythms differently.
Our rhythm may adjust based on your work hours, physical activity, and additional habits or lifestyle choices.
Factors that can change our circadian rhythms are:
• Mutations or changes in certain genes can affect our biological clocks.
• Jet lag or shift work causes changes in the light-dark cycle.
• Light from electronic devices at night can confuse our biological clocks.
Hormones like melatonin and cortisol may increase or decrease as part of your circadian rhythm. Melatonin is a hormone that makes you sleepy, and your body releases more of it at night and suppresses it during the day. Cortisol can make you more alert, and your body produces more of it in the morning. Although it’s a frequent problem, poor sleep can have severe consequences. Poor sleep can deplete your energy, lower your productivity, and increase the risk of diseases such as high blood pressure and diabetes.
Insomnia is a sleep disorder in which you have trouble falling or staying asleep.
This condition can be short-term (acute) when it lasts from 1 night to a few weeks or can last a long time (chronic) when it happens at least 3 nights a week for 3 months or more.
There are two types of insomnia: primary and secondary.
Primary insomnia: when your sleep problems aren’t linked to any other health condition or problem.
Secondary insomnia: when you have trouble sleeping because of a health condition, pain, medication, or substance use (like alcohol).
Symptoms of insomnia include:
• Sleepiness during the day
• Problems with concentration or memory
What causes insomnia?
Environmental, physiological, and psychological factors can all play a role in insomnia 
• Health problems.
• Behavioral and mental health disorders such as depression, stress, and anxiety.
• Unhealthy lifestyle and sleep habits. Going to bed at a different time each night or napping too long during the day. Exposure to “screen” devices like computers, televisions, and cell phones can also cause sleep problems
How can we prevent insomnia?
• Restricting the use of alcohol, caffeine, and tobacco products in the evening
• Avoiding late-night meals
• Limiting screen time prior to bedtime
• Maintaining a healthy diet and exercising regularly during the day
• Follow a consistent sleep schedule
Melatonin, often referred to as the sleep hormone, is a hormone that the brain produces in response to darkness. It is produced by the pineal gland in the brain and then released into the bloodstream. Darkness prompts the pineal gland to start producing melatonin while light causes that production to stop. It helps with the timing of the circadian rhythms and with sleep Being exposed to light at night can block melatonin production. Melatonin itself will not make you sleep. It simply lets your body know that it’s nighttime so you can relax and fall asleep. Melatonin created within the body is known as endogenous melatonin, but the hormone can also be produced externally. Exogenous melatonin is normally made synthetically.
Magnesium regulates neurotransmitters, which send signals throughout the nervous system and brain. It also regulates the hormone melatonin. Magnesium activates the parasympathetic nervous system, the system responsible for getting you calm and relaxed. It helps alleviate anxiety and depression; two mood disorders responsible for insomnia.
5-HTP Griffonia simplicifolia is a type of plant found in western parts of Africa. The seeds are used as a medicine because they contain a chemical called 5-hydroxytryptophan (5-HTP). This chemical works in the brain and central nervous system by increasing the production of the chemical serotonin. Serotonin can affect sleep, appetite, pain, and mood. People with low levels of tryptophan due to deficient diets create lower levels of 5-HTP and thus have lower levels of serotonin. This has been shown to be reflected in these people having higher levels of anxiety, depression, insomnia, and other mood disorders.  Tryptophan is an amino acid that is necessary for making proteins and other important molecules in our body, including some that are essential for optimal sleep and mood. Tryptophan can be converted into the molecule 5-HTP (5-hydroxytryptophan), which is used to make serotonin and melatonin that influence many functions in the body, including sleep, mood, and behavior.
Magnolia bark has long been regarded as a potent anxiolytic (anxiety-relieving) helping to lower anxiety and depression and reduce stress. Magnolia bark can also act as a sedative, directly helping to facilitate sleep. The active ingredients in the extracts of magnolia bark have been identified as the bi-phenolic isomers magnolol and honokiol. These compounds were shown to enhance the activity of GABA receptors.  GABA is a neurotransmitter that blocks impulses between nerve cells in the brain. Low levels of GABA may be linked to anxiety or mood disorders.
L-Theanine, a naturally occurring amino acid first discovered in green tea, is a well-known anti-anxiety supplement with proven relaxation benefits. l-theanine (γ-glutamyl-ethyl amide) has been shown to affect brain functions by relieving stress disorders, improving mood, and maintaining normal sleep.