Melatonin

What is melatonin?

Melatonin is a natural hormone produced by the pineal gland in the brain. It plays a crucial role in regulating the sleep-wake cycle and circadian rhythms[1][2]. Melatonin levels rise at night, helping signal to your body that it's time to sleep[1], before returning to normal during the day[2].  

How does melatonin work?

Synthetic melatonin is available as a dietary supplement and is commonly used to aid sleep[1]. This adds to your body’s natural supply of melatonin, so you fall asleep more quickly and you’re less likely to wake up during the night[2]. 

What is melatonin used for?

Melatonin is primarily used for people aged 55 and over to treat short-term sleep disorders such as insomnia and jet lag[3][4]. It can also be prescribed by specialists to help with longer-term sleep problems in some children and adults. 

Who can take melatonin?

Melatonin is typically safe for most adults. People aged over 55 can take it to help short-term sleep problems. Adults under the age of 55 and children with longer-term sleep problems can take melatonin if recommended by a specialist[2][3].  

Melatonin is not suit suitable for some people, however. Tell your doctor or pharmacist before taking it if: 

• You have had an allergic reaction to melatonin or any excipients in the medicine 

• You have kidney or liver problems 

• You have lupus, multiple sclerosis, rheumatoid arthritis, or any other autoimmune condition[2][10] 

Pregnant or breastfeeding women should also consult their doctor or pharmacist before using melatonin[7]. 

Please tell your doctor or pharmacist about any conditions you may have before starting melatonin, and always follow the instructions in the Patient Information Leaflet[15].

How do you take melatonin?

Melatonin is available in various forms, including tablets, capsules and liquid[9], but it most often comes as 2mg slow-release tablets such as the brand Circadin. 

It's usually taken 30 minutes to an hour before bedtime[8], but it’s best taken with food. If you’re taking slow-release tablets, you need to swallow them whole and not cut or crush them. 

What is the typical dosage of melatonin?

The typical dosage for melatonin ranges from 0.5 to 10 mg per day[3][11], but it’s most often prescribed as a 2mg slow-release tablet.  

It's best to start with a lower dose and gradually increase as needed[11]. For sleep disorders, taking melatonin 30 minutes to 2 hours before bedtime is recommended[11]. Sometimes your doctor or pharmacist will recommend you only take melatonin 2 to 3 times a week at first for short-term insomnia, or they can recommend you increase your dose to 2 to 3 tablets before bedtime if your problems are more long term. 

For jet lag, a dose of 3 mg taken at bedtime for up to five days is common[8]. You should take your first dose at your normal bedtime when you arrive at your destination, but this shouldn’t be before 8pm or after 4am. If you need more doses after the first one, they should be taken at a similar time, and you can increase your dose to two 3mg tablets if needed. 

You should use no more than a maximum of 16 treatment courses in a year. 

What do you do if you forget to take your melatonin?

If you forget to take your dose of melatonin, skip the missed dose and continue with your regular schedule the next night[8]. Do not take a double dose to make up for the missed one[8]. 

What do you do if you take too much melatonin?

Taking 1 or 2 extra tablets shouldn’t cause you any harm. However, if you’ve taken more than your prescribed dose, and you feel unwell, you should visit 111 online or call 111. 

If you need to go to A&E, you should ask someone to take you, or call 999 for an ambulance, taking with you the melatonin packet or leaflet, any remaining medicine, and any other medicines you take[12]. 

What are the side effects of melatonin?

Uncommon side effects of melatonin include[18]: 

• Headache 

• Dizziness 

• Nausea 

• Daytime drowsiness[5][6] 

• Dry mouth 

• Dry or itchy skin 

• Arm or leg pain 

Other less common side effects may include vivid dreams or nightmares, short-term feelings of depression, irritability, stomach cramps, diarrhoea, constipation, decreased appetite, and confusion[5][6]. It's generally considered safe for short-term use[5]. 

Serious side effects are rare and occur in less than 1 in 1,000 people. You should speak to your doctor or pharmacist if you’re feeling low or sad as this could be a sign of depression. 

You should call 111 immediately if you: 

• Experience blurred vision or other eyesight changes 

• Feel faint or pass out 

• Feel confused or dizzy 

• Have bleeding that doesn’t stop, unexplained bruising or blood in your pee 

In very rare cases, melatonin can cause a serious allergic reaction, known as anaphylaxis. 

You should call 999 immediately if: 

• Your lips, mouth, throat, or tongue swell up 

• You’re experiencing breathing difficulties 

• Your throat feels tight or struggling to swallow 

• Your skin, tongue, or lips turn blue, grey, or pale 

• You become confused, drowsy, or dizzy 

• Someone faints and can’t be woken 

• A child is limp, floppy, or not responding as normal 

• There’s a rash that’s swollen, raised, itchy, blistered, or peeling 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[15].

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice

Medicines you can and can't take with melatonin

Melatonin can interact with several medications, particularly those that increase or decrease the drowsy-making effects of melatonin. These include: 

• Benzodiazepines (e.g., temazepam, diazepam) 

• Opiates (e.g., codeine, morphine) 

• Certain antibiotics like quinolones or rifampicin 

• Epilepsy medication (e.g., carbamazepine) 

• Schizophrenia medication (e.g., thioridazine) 

• Insomnia medication (e.g., zaleplon, zolpidem, zopiclone) 

• Blood pressure medications (e.g., nifedipine) 

• Immunosuppressants (e.g., cyclosporine) 

• Antidepressants (e.g., fluvoxamine, amitriptyline) 

• Diabetes medications[14][15] 

It's best to avoid taking melatonin with alcohol, and other sedatives. Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[15]. 

Frequently asked questions about Melatonin

How long does it take for melatonin to work? 

It takes around 1 to 2 hours to start working. 

How long do I need to take melatonin for to treat insomnia? 

For short-term insomnia, it will be around 1 to 4 weeks, although it can be up to 13 weeks depending on your circumstances. 

It can help to look at lifestyle changes in conjunction with melatonin to help improve your insomnia symptoms. 

How does melatonin work for jet lag? 

There is evidence that melatonin reduces the severity of your jet lag symptoms and can help reduce your recovery time by a day to a day and a half. 

Can you take melatonin every night? 

For most individuals, melatonin is safe to take occasionally for 2-3 months[16]. If sleep issues persist, consult your doctor or pharmacist as there may be an ongoing cause[16]. 

Does melatonin cause weight gain? 

Melatonin does not directly affect weight. However, better sleep may lead to more energy for exercise, which can help with weight control[16]. 

Can I get addicted to melatonin? 

If you take it as prescribed for short periods, you’re unlikely to become addicted to melatonin. 

However, if you’ve been taking melatonin for a long time, speak to your doctor or pharmacist before you stop taking it or if you’re worried about being potentially addicted to it. They can help you come off it gradually. 

Can I buy melatonin without a prescription? 

You can’t buy melatonin in the UK in a shop as it is a prescription-only medicine. 

It is available to buy in some countries in health shops or online. These are not authorised for sale in the UK and you should not order it online as they may not be legitimate medicines. 

Is melatonin good for anxiety? 

Melatonin is not recommended for treating anxiety. It's best to speak with a healthcare provider for anxiety management[16]. 

Can melatonin be used during pregnancy or breastfeeding? 

Speak to your doctor or pharmacist before using melatonin during pregnancy or lactation[17]. 

Can I drive or ride a bike while taking melatonin? 

If melatonin makes you sleepy, gives you blurred vision, or makes you feel dizzy, confused or unable to concentrate, then you should not drive or ride a bike. It's an offence to drive if your ability to drive safely is impacted. 

Do I need to avoid any food or drink, including alcohol, while taking melatonin? 

You should avoid drinks that contain caffeine (tea, coffee, cola, energy drinks) as it stops melatonin from working properly. You should also avoid alcohol as it too affects how melatonin works.

For the official NHS guide to melatonin, visit their website.

References

[1] Melatonin: What It Is & Function - Cleveland Clinic 

[2] Melatonin: A hormone used for sleep problems - NHS 

[3] Melatonin: Benefits, Uses, Side Effects, and Dosage - Healthline 

[4] MELATONIN - Uses, Side Effects, and More - WebMD 

[5] Melatonin side effects: What are the risks? - Mayo Clinic 

[6] 9 Melatonin Side Effects to Watch Out For, Doctors Say 

[7] Side effects of Melatonin 

[8] How and when to take melatonin - NHS 

[9] Melatonin: Uses, Side Effects, Dosage (Kids/Adults) - Drugs.com 

[10] Who can and cannot take melatonin - NHS 

[11] Melatonin Dosage: How Much Should You Take - Sleep Foundation 

[12] Melatonin Overdose - WebMD 

[13] Is It Possible to Overdose on Melatonin? Here's What to Know - Healthline 

[14] Melatonin Interactions Checker - Drugs.com 

[15] Melatonin – Patient Information Leaflet - emc 

[16] Melatonin Facts: Expert Answers to Frequently Asked Questions 

[17] FAQs - Phytomelatonin 

[18] Circadin 2 mg Prolonged-release Tablets – Summary of Product Information - emc