Melatonin Dosage: Can You Have Too Much of a Good Thing?

July 17, 2017
Melatonin dosage - Dr. Axe

For millions of people, melatonin might be the answer to avoiding another terrible slumber. We know that sleep is highly important to maintaining the health of the entire body and warding off acute and chronic health issues. But what is melatonin? It’s actually a hormone that is responsible for setting our sleep-wake cycle, so long as you have the proper melatonin dosage.

According to new Centers for Disease Control and Prevention study, one out of three American adults are not getting enough sleep on a regular basis. (1) At the top of the list for melatonin common uses is definitely assistance when it comes to a good night’s rest as a natural sleep aid. Melatonin is used to treat sleep issues resulting from jet lag or insomnia, and it’s even used to help treat certain cancers. (2) Scientific research has shown that it can benefit cancer patients, specifically those diagnosed with breast or prostate cancer. Those are two hormonally linked cancers so it makes since that a hormone like melatonin can play a pivotal role in their treatment.

Melatonin is naturally produced by our bodies, but caffeine, alcohol and tobacco use can all lower melatonin levels in the body. So can working the night shift or having poor vision. For some people, melatonin can help get their inherent rhythms get back on track. Let’s talk more about who melatonin can help, the benefits of melatonin and what melatonin dosage is best for your particular health concern.


What Is Melatonin?

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone secreted by the pineal gland in the brain. The pineal gland is located just above your middle brain and is only the size of a pea. Its synthesis and release are stimulated by darkness and suppressed by light.

Melatonin is responsible for maintaining your body’s circadian rhythm. Why is that important? Your circadian rhythm is the fancier term for your own person internal clock, which also runs on a 24-hour schedule just like the day. This internal clock plays a critical role in when we fall asleep and when we wake up.

When it’s dark, your body produces more melatonin, but when it’s light, the production of melatonin goes down. This is why people who are blind or work night hours can have problems with their melatonin levels. But for anyone, a lack of exposure to light during the day or exposure to bright lights in the evening can disrupt the body’s normal melatonin cycles.

When you’re exposed to light it stimulates a nerve pathway from the retina in the eye to an area in the brain called the hypothalamus. This is where the suprachiasmatic nucleus (SCN) is located, and the SCN initiates the turning on of the pineal gland. Once the SCN turns on the pineal gland, it starts making melatonin, which is then released into your bloodstream.

The precursor to melatonin is serotonin, a neurotransmitter that’s derived from the amino acid tryptophan. Within the pineal gland, serotonin is processed to yield melatonin. For this to be possible, a naturally occurring chemical called acetylserotonin must act as the intermediary. Serotonin produces acetylserotonin, which is then converted into melatonin. Besides its role as a precursor in the synthesis of melatonin, acetylserotonin is also known to have anti-depressant, anti-aging and cognitive-enhancing benefits. (3)

Once serotonin is transformed into melatonin, the two neurotransmitters don’t interact again. Like melatonin, serotonin is known to affect the way you sleep and it transmits signals between nerve cells that alter your everyday brain functions. But many of the health benefits that are thought to be due to increasing serotonin levels may actually be coming from serotonin’s ability to make melatonin production possible.

The pineal gland typically starts producing melatonin around 9 p.m. Your melatonin levels then increase sharply and you begin to feel more sleepy. If your body is running as it should, your melatonin level remains elevated while you sleep, for a total of approximately 12 hours. Melatonin levels drop, and by around 9 a.m., the level is back to a barely detectable level where it remains during the day. (4)

Melatonin is also crucial to female reproductive health as it plays a role in controlling the timing and release of female reproductive hormones. It helps decide when a woman starts to menstruate, the frequency and length of menstrual cycles, as well as when a woman stops menstruating completely (menopause).

Young children have the highest levels of nighttime melatonin. Many researchers believe that melatonin decreases as we age. (5) If this is true, then it could explain why older people don’t tend to sleep as well as they did when they were younger.


11 Melatonin Benefits 

1. Natural Sleep Aid

Melatonin for sleep is by far its best known usage as a natural remedy. When it comes to sleep trouble, conventional medical treatment typically involves pharmaceutical drugs, but these medications frequently lead to long-term dependence and come with a laundry list of possible side effects. This is why many people want to find something more natural to help them have a more restful night’s sleep.

Research suggests that supplementing with melatonin may help people with disrupted circadian rhythms, such as people who work the night shift and people who have jet lag. Melatonin supplementation may also help individuals sleep better who have chronically low melatonin levels, like people with schizophrenia, who have poor sleep quality.

A 2012 study published in Drugs & Aging analyzed the effects of prolonged release melatonin in the treatment of insomnia in patients 55 years or older. In the European Union, two milligrams of prolonged release (PR) melatonin is approved for the treatment of primary insomnia characterized by poor sleep quality. The randomized, double-blind trial found that two milligrams of melatonin PR given one to two hours before bedtime was associated with significant improvements compared to a placebo in sleep quality and length, morning alertness, and health-related quality of life. The study also found that whether the melatonin dosage (two milligrams PR) was short- or long-term, there was no dependence, tolerance, rebound insomnia or withdrawal symptoms. (6)

2. Potential Treatment for Breast and Prostate Cancer

Several studies suggest that low melatonin levels may be associated with breast cancer risk. To determine melatonin’s effectiveness at stopping tumor growth, one group of researchers evaluated the action of melatonin dosage on the growth of breast tumors in vitro (using human cancer cells) and in vivo (using mice). The researchers found that melatonin may inhibit tumor growth and cell production, as well as block the formation of new blood vessels in estrogen receptor-negative breast cancer models. This 2014 research shows melatonin’s potential as a therapeutic agent for breast cancer. (7)

Another study looked at women who were taking the chemotherapy drug tamoxifen for breast cancer but not seeing any improvement. With the addition of melatonin to their treatment regimens, researchers found that tumors modestly shrank in more than 28 percent of the women. (8)

Studies also show that men with prostate cancer have lower melatonin levels than men without the disease. One study published in Oncology Reports aimed to verify whether melatonin might modulate the growth of androgen-dependent prostate cancer cells. The results demonstrated that melatonin can significantly inhibit the proliferation of prostate cancer cells. (9)

Combined, these studies show melatonin’s great promise as a potential natural treatment for cancer.

3. Decreases Negative Menopause Symptoms

Melatonin supplements have been shown to improve sleep problems experienced during menopause. In a study of perimenopausal and menopausal women ages 42 to 62, within six months of a daily melatonin dosage, most of the women reported a general improvement of mood and a significant mitigation of depression. The findings of this study appear to demonstrate that melatonin supplementation among perimenopausal and menopausal women can lead to recovery of pituitary and thyroid functions toward a more youthful pattern of regulation. (10)

This is great news because it shows that melatonin can help decrease common negative perimenopause symptoms and menopause symptoms, like sleeping problems.

4. Heart Disease Helper

Multiple studies suggest that melatonin has heart-protective properties. Specifically, research shows that when it comes to cardiovascular health, melatonin has anti-inflammatory and antioxidant effects. It also can help lower blood pressure and cholesterol. It seems to have cardioprotective properties via its direct free radical scavenger activity. Overall, the protective abilities of melatonin may be able to help reduce and treat cardiovascular diseases. (11)

Melatonin notables - Dr. Axe

5. Fibromyalgia and Chronic Pain Relief

Fibromyalgia symptoms include long-term and widespread pain in muscles and connective tissues, without any specific cause. A randomized, placebo-controlled study of 101 patients with fibromyalgia syndrome evaluated melatonin’s effectiveness at reducing symptoms. It found that patients experienced a significant reduction in their symptoms when they took a melatonin dosage either alone or in conjunction with the antidepressant fluoxetine (Prozac).

The group who took only melatonin was given a daily melatonin dosage of five milligrams while the other group took three milligrams of melatonin and 2o milligrams of the antidepressant. (12) Other studies suggest that melatonin might be able to help with other chronic painful conditions, like migraine headaches.

6. Immune System Strengthener

Research is showing that melatonin has strong antioxidant effects and may help strengthen the immune system. A 2013 scientific review calls melatonin an “immune buffer” because it appears to act as a stimulant in an immunosuppressive condition, but it also behaves as an anti-inflammatory compound when there’s an intensified immune response, like in the case of acute inflammation. (13)

7. Eases Jet Lag

Jet lag is a temporary sleep disorder experienced by air travelers who rapidly travel by plane across multiple time zones. It happens as a result of the slow adjustment of the body clock to the destination time, which causes sleep and wakefulness to be out of sync with the new environment. Supplementing with melatonin may be able to help “reset” your sleep and wake cycle when you experience dreaded jet lag.

A scientific review of a large number of trials and studies all involving melatonin and jet lag finds that melatonin is “remarkably effective in preventing or reducing jet-lag, and occasional short-term use appears to be safe.” The researches found that in nine out of 10 trials, when melatonin was taken close to the target bedtime at the destination (10 p.m. to 12 a.m.) there was a decrease in jet lag from crossing five or more time zones. The researchers also observed that daily doses of melatonin between 0.5 and five milligrams worked similarly well, but subjects did fall asleep faster and sleep better after taking five milligrams compared to 0.5 milligrams.

When a melatonin dosage above five milligrams was given, it did not produce any better results. Another key conclusion is that the timing of a melatonin dose is key because if it’s taken too early then it can delay adaptation to the new time zone. The incidence of other side effects from melatonin dosage was found to be low. (14)

8. Better Outcomes for Autism in Children

Research has shown that melatonin can help children with developmental issues like autism. This is important, particularly with autism rates on the rise.

A 2011 scientific review published in Developmental Medicine and Child Neurology evaluated 35 studies that had melatonin-related findings involving autism spectrum disorders, including autistic disorder, Asperger’s syndrome, Rett syndrome and other common developmental disorders. After reviewing the numerous studies, researchers concluded that melatonin supplementation in autism spectrum disorders is linked to better sleep parameters, improved daytime behavior and minimal side effects. (15)

9. May Ease Tinnitus

Research suggests that melatonin may serve as a natural tinnitus treatment. Tinnitus is a condition that causes noise or ringing in the ears. For many people, tinnitus symptoms eventually go away as your auditory sensations and nerves near your ears adjust, but for those who are dealing with tinnitus for a long period of time, it can lead to other health issues like anxiety and depression.

The anti-oxidative properties of melatonin may contribute to its ability to alleviate tinnitus. Researchers at the Ohio State University Eye and Ear Institute conducted a study involving 61 participants. After taking 3 milligrams of melatonin nightly for 30 days, the participants experienced a significantly greater decrease in tinnitus symptoms. Taking melatonin also helped to improve the quality of sleep in patients with chronic tinnitus. (16)

10. Relieves Bladder Dysfunction

Melatonin receptors are found in the bladder and the prostate. It works to prevent elevations in levels of malondialdehyde, which is a marker for oxidative stress. Through the reduction of oxidative stress, melatonin helps to combat age induced bladder dysfunction. It also limits bladder contractions and induces relaxation, helping to relieve issues like overactive bladder.

An article review published in Current Urology found that, although the exact mechanisms of action are not yet fully understood, there is a strong body of evidence suggesting that a melatonin imbalance can have a detrimental effect on bladder dysfunction. (17)

And a 2012 study suggests that nightly production of melatonin helps to improve sleep and reduce habitual nightly voiding. Melatonin also increases bladder capacity and decreases urine volume due to its effects on the central nervous system. (18)

11. Helps Relieve Stress

Melatonin levels change when you are experiencing stress. Stress decreases melatonin concentrations at night and increases melatonin production during the day, which is due to the increase of cortisol, the stress hormone. Melatonin can help to relieve stress by controlling the level of stimulation experienced by the body. (19)

If you are feeling anxious, melatonin helps to ease anxiety symptoms like daytime fatigue, drowsiness, insomnia and restlessness. It also promotes a calm mood and it supports brain function.


Melatonin Interesting Facts

  • Melatonin is a hormone secreted by the pineal gland in the brain.
  • The precursor to melatonin is serotonin, a neurotransmitter that’s derived from the amino acid tryptophan.
  • When it’s dark, the secretion and production of melatonin increases.
  • When it’s light, the secretion and production of melatonin decreases.
  • Jet lag, shift work and poor vision can disrupt melatonin cycles.
  • Caffeine, tobacco and alcohol can all lower levels of melatonin in the body.
  • Young children have the highest levels of nighttime melatonin.
  • Blue light emitted by screens (TV, computer, phone, etc.) suppresses melatonin levels, making it more difficult to fall asleep.
  • Melatonin can be helpful for children with developmental disabilities like autism.
  • Some foods that naturally increase melatonin production include oats, bananas, tart cherries, walnuts, pineapple and barley.
  • Daytime exercise and light exposure promote regular circadian rhythm of melatonin and help ensure higher levels at night.

How to Use Melatonin and Proper Melatonin Dosage

You can easily find melatonin at your nearest health store or online in a number of forms: capsule, tablet, liquid, lozenge (that dissolves under the tongue) and topical cream.

Can you overdose on melatonin? As with any medicine or supplement, it’s possible to take too much melatonin. Most doctors and researchers recommend no more than five milligrams per day, but recommendations can vary by person and condition.

Melatonin pills are a very common selection, especially the sublingual lozenges designed for rapid absorption. Another option is topical melatonin, which is said to help skin quality as well as sleep. Researchers have found that melatonin penetrates into the outer layer of skin, reinforcing the skin’s capacity for repair, renewal and revitalization during the night. (15)

There’s currently no recommended dose for melatonin supplements. It’s important to know that people react differently to taking melatonin. For people who are very sensitive, lower doses appear to work better. For sleep troubles, you should know that the right dose of melatonin will have you sleeping well with no daytime tiredness or irritability, so if you’re always tired, melatonin is a great option to reverse that trend.

It’s always a good idea to start off with a very low dose of melatonin and see how you do. You can follow supplement directions on the label or consult an expert if you are feeling unsure.

Melatonin Dosage for Children

Melatonin for children is sometimes helpful. If your child has a neurodevelopmental disorder that causes sleep trouble, your doctor may prescribe melatonin. It’s also used to treat symptoms of ADHD, autism, cerebral palsy and developmental disabilities in children. However, higher doses of melatonin in young people may cause seizures. It also  interfere with development during adolescence because of potential effects on hormones. Always consult a doctor before giving melatonin to a child.

Melatonin Dosage for Adults

For jet lag: 0.5 to five milligrams of melatonin by mouth one hour before bedtime at final destination has been used in several studies. Another approach that has been used is one to five milligrams one hour before bedtime for two days prior to departure and for two to three days upon arrival at final destination. (16)

For circadian rhythm sleep disorders in people with and without vision problems: a single dose of 0.5 to five milligrams by mouth before bed or as a daily dose for one to three months.

For delayed sleep phase syndrome: 0.3 to six milligrams by mouth (with five milligrams being most common) daily before sleeping for two weeks to three months.

There are many other melatonin dosage suggestions for various health concerns based on scientific research, traditional use and expert advice. (17)

When it comes to melatonin dosage for sleep, people commonly take a pill too soon before bed, decide it isn’t doing the job quick enough and take another. Some people also wake up during the night and take another melatonin dosage. Although this might not cause any serious problems, this is not the right or safest way to use melatonin because the more you take the more likely it is that you’ll experience unwanted side effects.

If you have cancer, you should always speak with your doctor before taking melatonin.

Melatonin dosage guidelines - Dr. Axe

Melatonin Possible Side Effects and Interactions 

Is melatonin safe? It’s quite safe when taken by mouth for short periods of time. It can also be safe for some people to take it long term. Melatonin has been used safely for up to two years. (18)

Some people experience vivid dreams or nightmares when taking melatonin, and taking too much melatonin can disrupt circadian rhythms. Other possible side effects of melatonin include headache, dizziness, daytime sleepiness, short-term feelings of depression, stomach cramps, irritability and decreased libido. For men, breast enlargement (gynecomastia) and reduced sperm count are also possible. If you experience drowsiness the morning after taking melatonin, try taking a lower dose.

Pregnant or nursing women should not take melatonin. Melatonin is a hormone so if you have a history of hormonal-related health issues then you should only use melatonin under the supervision of a doctor.

Melatonin can decrease the effectiveness of some medications while actually decreasing side effects from others. In general, these are some possible medication interactions to be aware of:

  • Antidepressant medications
  • Antipsychotic medications
  • Benzodiazepines
  • Birth control pills
  • Blood pressure medications
  • Beta-blockers
  • Blood-thinning medications (anticoagulants)
  • Interleukin-2
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Steroids and immunosuppressant medications
  • Tamoxifen

Speak with your doctor first before taking melatonin if you have any ongoing health concerns or are currently taking any other medications.

Never drive or use machinery within five hours of taking melatonin. If you take an excessive amount of melatonin intentionally or by accident, seek medical attention immediately.


Final Thoughts on Melatonin Dosage

Remember that more is not necessarily better when it comes to melatonin. Higher melatonin dosage can actually lead to side effects that disrupt your rest. However, when used properly, melatonin has been shown to help several different sleep issues, whether it’s the temporary woes of jet lag or a more chronic sleep issue like insomnia. The scientific findings when it comes to cancer and heart health are also highly impressive.

I recommend keeping your dose and duration of melatonin on the lower side unless a health professional advises you otherwise based on your specific health concern. If you’ve been taking melatonin for two weeks or longer and don’t see any improvement in your sleep, then your body’s sleep issues might be the result of another issue, like anxiety or depression, and you’ll have to address these issues differently.

Read Next: Can’t Sleep? 20 Strategies to Fall Asleep Fast!


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