Can I take 20mg of melatonin?

Quick Answers

Melatonin dosage recommendations vary, but generally start low at around 1-5mg per day. While some people may take up to 20mg, high doses can lead to side effects like daytime drowsiness, irritability, headaches, and nausea. It’s best to start with the lowest effective dose for your needs. Talk to your doctor about the right melatonin dosage for you.

What is Melatonin?

Melatonin is a hormone produced naturally by the pineal gland in the brain that helps regulate the sleep-wake cycle. It rises in the evening to promote sleep and falls in the morning to help wake you up. Melatonin supplements provide extra melatonin to help adjust this cycle for people with sleep disorders or jet lag.

How it Works

Melatonin works by binding to receptors in the brain that help induce sleepiness. It shifts the timing of the body’s internal clock to make you feel more sleepy earlier or later. This helps reset your circadian rhythm so you fall asleep and wake up when desired.


Some common uses of melatonin supplements include:

– Jet lag: Helps reset the body clock after travel across time zones.

– Shift work disorder: Helps adjust the sleep cycle for night shift workers.

– Delayed sleep phase disorder: Helps fall asleep earlier for “night owls”.

– Insomnia: Helps fall asleep faster and stay asleep. Especially helpful for older adults.

– Sleep problems in ADHD, autism, etc: Helps regulate sleep cycles disrupted by disorders.

– Seasonal affective disorder (SAD): Helps with winter depression linked to circadian rhythms.

So in summary, melatonin is mainly used for various circadian rhythm sleep disorders.

Melatonin Dosage Guidelines

There is no universally agreed upon dosage for melatonin. Recommendations vary widely from 0.2mg up to 20mg per day. However, there are some general guidelines to follow:

Start Low

It’s best to start with a low dose around 1-5mg taken 30-60 minutes before bedtime. This aligns closely with the body’s own melatonin production. Starting low can help avoid side effects.

Increase Slowly

The dosage can be increased by 1-5mg per week if a lower dose is not effective. Most people respond to doses between 0.5-5mg, but some need more. Increase slowly up to 10mg max.

Time it Right

Take melatonin 30-90 minutes before your target bedtime. This allows time for it to take effect as you prepare for sleep. Avoid taking it earlier in the evening or it may make you sleepy too soon.


Take melatonin at the same time each evening for best results. Consistency is key for aligning your circadian rhythm.

Less is More

Research suggests that lower doses around 0.3-5mg work just as well or better than higher doses. Taking more does not always increase effectiveness.

Watch for Side Effects

Higher doses carry greater risk of side effects like daytime drowsiness, irritability, anxiety, nausea, headaches, and fogginess. Start low and increase carefully.

20mg Melatonin Dosage

While some people may take 20mg of melatonin for sleep, most experts consider this a very high dose with increased side effect risks.

Potential Benefits

Some users report that 20mg melatonin helps them:

– Fall asleep faster at night
– Stay asleep longer through the night
– Feel more well rested in the morning
– Reduce late night awakenings or tossing and turning

It may help set the circadian rhythm earlier for night owls with delayed sleep phase.

Possible Side Effects

However, potential side effects from 20mg melatonin may include:

– Excessive daytime drowsiness, grogginess
– Headache, migraine
– Irritability, anxiety, confusion
– Nausea
– Disorientation upon waking
– Vivid dreams or nightmares

These tend to occur more often at higher doses. Extended release 20mg doses taken over several hours may reduce, but not eliminate, side effects.

Tolerance Build Up

Taking melatonin long-term at a high dose can lead to tolerance where it becomes less effective over time. Your body may get used to the higher dose and reduce sensitivity.

Possible Hormone Disruption

Animal studies on very high melatonin doses raised concerns about potential reproductive hormonal effects. While not definitively shown in humans, some doctors monitor use in adolescents and women.

Who Should Avoid 20mg Melatonin?

The following groups should use extra caution and speak with a doctor before considering melatonin doses of 20mg:


Most pediatricians do not recommend melatonin for children except in rare cases. Melatonin production levels are already high in kids. Large doses could affect development.


Since melatonin may impact hormones like estrogen, some doctors monitor use in adolescents going through puberty.

Pregnant or Breastfeeding Women

There is insufficient safety data for pregnant or nursing mothers. Potential hormonal effects could impact the baby.

People on Medications

Melatonin can interact with sedatives, blood thinners, diabetes medications, antidepressants, and immune suppressants. Large doses are not recommended.

People with Autoimmune Disorders

Melatonin is involved in immune system regulation, so should be used with caution in people with autoimmune conditions like lupus, MS, or rheumatoid arthritis.

How to Take 20mg Melatonin

If you and your doctor decide 20mg melatonin is appropriate for your situation, here are some tips on taking high-dose melatonin:

Extended Release Tablets

Take an extended release 20mg tablet 1-2 hours before bedtime. This gradually releases melatonin to reduce side effects.

Lower Strength Doses

Take several regular strength 3-5mg tablets for a combined 20mg dose before bed. This may also provide a more gradual effect.

Time it Right

Make sure to take the full 20mg dose at least 2 hours before your desired bedtime. This allows time for it to make you sleepy without causing morning grogginess.

Be Consistent

Take the 20mg dose at the exact same time each night to keep your circadian rhythms in sync. Inconsistency can diminish effectiveness.

Avoid Alcohol

Do not drink alcohol when taking high dose melatonin, as combining depressants increases side effects like drowsiness, dizziness and impairment.

Watch for Side Effects

Pay close attention to any side effects like headaches, nausea, daytime fatigue or mood changes. Report concerns to your doctor promptly.

Safety Tips for High Dose Melatonin

If taking 20mg melatonin, keep these safety recommendations in mind:

Consult Your Doctor

Discuss with your doctor first before starting high dose melatonin. Make sure the benefits outweigh any risks based on your health.

Start Low & Go Slow

Consider starting with 1-5mg for a week before increasing dose. This allows your body to adjust and reduces side effects.

Avoid Alcohol & Sedatives

Don’t take melatonin with alcohol, sedatives or other sleep medications as they compound drowsiness.

Avoid Driving

Don’t drive or operate heavy machinery for 4-5 hours after taking high dose melatonin due to impairment risks.

Beware Drug Interactions

Make sure 20mg melatonin does not interact with other medications you take like blood thinners, antidepressants etc.

Watch for Allergies

Discontinue use if any signs of allergic reaction occur, such as rash, itching, swelling, or trouble breathing.

Talk to Your Doctor if Pregnant

There is limited safety data on melatonin use in pregnancy. Discuss risks/benefits.

Avoid Regular Long-Term Use

High dose melatonin should be used short term only unless advised by your doctor. Do not become dependent.

Frequently Asked Questions

Is it safe to take 20mg of melatonin daily?

Taking 20mg melatonin daily is generally not recommended. Lower doses of 0.5mg to 5mg have the best safety profile and are usually effective for most people. High doses may cause side effects and long term risks are unknown.

Can I take 20mg of melatonin long term?

Long term use of high dose 20mg melatonin is not advised. The risks are unknown and it may cause hormonal changes or tolerance over time. Short term use for jet lag, shift work or insomnia is safer under medical guidance.

What happens if I take too much melatonin?

Melatonin overdose can cause excessive drowsiness, confusion, headache, anxiety, irritability, nausea, and disorientation. If you have concerning symptoms, contact your doctor or poison control center.

Can I take melatonin with alcohol?

It is not recommended to mix melatonin with alcohol or sedatives. The combined depressive effects can slow breathing, lower blood pressure, impair motor control and judgment. Start with lower melatonin doses if consuming alcohol.

Should I take melatonin every night?

Regular use of melatonin each night is generally not recommended, especially at higher doses. Melatonin should be used as needed short term, not as a daily sleep aid due to potential risks, tolerance, and effectiveness loss over time.


While melatonin is a relatively safe supplement, taking a high 20mg dose can increase the risks of side effects and unknown long term effects. Most experts recommend starting with the lowest effective dose, usually between 0.5-5mg taken 30-60 minutes before bedtime. The maximum suggested dose is around 10mg. High dose melatonin at 20mg should be taken only occasionally and under medical supervision, especially for high risk groups. Always discuss melatonin use with your doctor and report any side effects. Proper dosage and scheduling is key to balancing effectiveness with safety.

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