What is the Right Melatonin Dosage?

A Different Kind of Sleep Medicine

There are lots of different kinds of sleep aids out there – from conventional z-drugs to drowsy antihistamines, such as promethazine.

But melatonin, a hormone produced in the brain and also available as a medicine, is a little different. That’s because it is a natural part of your body’s system that regulates your circadian rhythm. When you take melatonin, you are just reinforcing a system that works naturally already.

Here, we’re revealing everything you need to know about melatonin dosages – from the levels of melatonin you need to the side effects if you have too much.

What is Melatonin?

Melatonin is a hormone produced in the pineal gland in the brain. It is known as the ‘sleep hormone’ thanks to its role in the process that regulates your sleep-wake cycle.

Natural melatonin production makes you sleepy. When night comes and it gets dark, your brain produces and releases the hormone, which signals to the rest of your body to sleep. Then, when it gets light, melatonin production slows and you feel more awake.

It is thought that people who have trouble sleeping often have low melatonin levels. Taking melatonin can help.

Typically, melatonin is recommended for the treatment of insomnia and short-term sleep disruptions, including from jet lag and shift work.

However, the hormone is also used to treat other conditions including epilepsy, autism spectrum disorder, and attention deficit hyperactivity disorder in children. It is available for the treatment of headaches in older adults too.

Note. In the UK, melatonin is only available by prescription. That means you won’t be able to get it over the counter – but only from a licensed pharmacy. This differs from countries like the USA, where the Food and Drug Administration (FDA) does not regulate it as a medicine, but as a dietary supplement.

For the treatment of sleep disorders, we recommend that you start with one 2mg tablet of melatonin, about half an hour before you go to bed. Clinical trials have shown that this melatonin dosage helps people sleep 7 minutes faster on average.

And for jet lag? Starting a few days before you arrive, take a 2mg dose of melatonin two hours before what will be your bedtime at the destination to which you are travelling.

While most courses of the hormone are up to 4 weeks, you can use it for longer. Melatonin is licensed for short-term use for up to 13 weeks. Just be careful. While they are rare, the side effects of melatonin can be unpleasant. Avoiding higher doses can help to keep the risk to a minimum.

Talk to a doctor or pharmacist before you use melatonin. If you or your child is using melatonin for anything other than to improve sleep quality, follow the advice of your healthcare provider.

What are the Side Effects of Melatonin?

Keeping to a low dose of melatonin can help to reduce the risk of side effects. While these are generally rare, they can include:

Daytime drowsiness or sleepiness
Headache
Stomach ache and nausea
Irritableness and restlessness
Strange dreams
Dry mouth and skin
Pains in your arms and legs

More serious side effects happen to fewer than 1 in a 1,000 people. But if you do experience any of the following after taking melatonin, seek immediate medical advice:

Blurry vision
Loss of consciousness, or extreme dizziness
Blood in your urine, or unexplained bruising
Psoriasis
Feeling sad or low
Heart palpitations or chest pain

Who Should Not Take Melatonin?

The use of melatonin is not recommended for everyone. If any of the following apply to you, it’s important that you only use the hormone with caution:

You are on blood thinners. Melatonin may make your blood thinner. If you are on anticoagulants or medications like warfarin, it is important that you talk to a healthcare professional first before taking melatonin.
You are on medication for high blood pressure (hypertension). Melatonin may lower your blood pressure. Combining it with medications that control your blood pressure may cause complications.
You are pregnant or breastfeeding. Melatonin may be unsafe when used by pregnant women or those who are breastfeeding. It may also function as a contraceptive.
You are taking antidepressants. Melatonin may interact with drugs including fluvoxamine.

Melatonin, at any dosage, should only be used by those who have a medical need for it. It is a drug – and can be harmful if taken irresponsibly.

Key Takeaways

Melatonin has been shown to help people sleep better. A 2mg melatonin dosage should be enough for most people to improve their sleep.

It is important that you don’t exceed the recommended dose – particularly if you are on other medication – to reduce the risk of side effects.

FAQs

Why Can Melatonin Be Prescribed to Help with Jet Lag?

Melatonin can help with jet lag, as it is a hormone that regulates your sleep-wake cycle. By making you feel sleepy, taking melatonin can make it easier for you to schedule your sleep pattern across time zones.

Is the Dosage of Melatonin in the Morning or in the Evening?

It is usually recommended that you take melatonin in the evening, about half an hour before you go to sleep. If you are taking it for jet lag, however, take the hormone about 2 hours before your expected bedtime in your destination country – a few days before you travel.

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.