Melatonin Tablets - Prolonged Release

What is melatonin?

Melatonin tablets are a prescription treatment used to help relieve the symptoms of jet lag in adults. They contain melatonin, a substance your body naturally produces to help control when you feel sleepy and when you wake up. Taking melatonin tablets can help your body adjust more quickly to a new time zone, so you can settle into your normal sleep pattern sooner.

How does melatonin work?

Melatonin tablets work by mimicking and reinforcing your body’s natural sleep signals.

Your body usually produces melatonin when it gets dark, as this tells your brain that it’s time to sleep. However, when you travel across time zones, your body gets out of sync with your new location and may start releasing melatonin at the wrong time.

Melatonin tablets help shift this timing back into place. They increase the level of melatonin in your body at the right time, signalling to your brain that you’re ready to sleep in your new time zone.

How long do melatonin tablets take to work?

Melatonin tablets usually start to work within 1–2 hours of taking them. They’re taken in the evening, just before you’re ready to go to bed in your new time zone.

You may start to notice an improvement from the first night, but it can take a few days of taking melatonin consistently for your sleep pattern to fully adjust.

How long does melatonin last?

Melatonin tablets release the hormone slowly over several hours while you sleep. This prolonged release helps maintain a steady level of melatonin in your body throughout the night, making it easier to stay asleep.

The effects usually last for most of the night, helping to support a full night’s sleep as your body clock resets.

How to take melatonin tablets for jet lag

Melatonin prolonged release tablets should be swallowed whole, with a drink of water and food. Do not cut, crush or dissolve them to allow them to release gradually throughout the night.

When you arrive at your destination, take your first dose at your normal bedtime. The NHS suggests that this should not be before 8pm or after 4am.

While you’re taking them, try to keep things consistent by taking your dose at the same time each night. This helps your body get into a new routine more quickly and supports your sleep pattern as it adjusts.

Melatonin dosage

When taking melatonin for jet lag, the usual dose is one 2mg tablet.

You may be able to increase your dose up to two 3mg tablets, but only on the advice of a healthcare professional.

When taken for jet lag, it should be taken for a maximum of five days, and if you feel like you need to take doses after this, speak with your pharmacist first.

Important: You should not take more than 16 treatment courses of melatonin in one year.

Benefits of Melatonin

• Helps your body adjust more quickly to a new time zone.
• Makes it easier to fall asleep at your intended bedtime.
• Supports staying asleep through the night with prolonged release.
• Can reduce jet lag symptoms like fatigue and disrupted sleep patterns.
• Short-term treatment that helps restore your normal sleep routine.

Melatonin side effects

Melatonin is generally well tolerated, and most people do not experience side effects when taking it for a short period to help with jet lag.

If side effects do occur, they are usually mild and may include:

• feeling sleepy or dizzy
• headaches
• slight nausea
• changes in alertness the next day

These effects are usually temporary and should improve as your body adjusts, but if they persist or become bothersome, you should speak to a pharmacist or doctor for advice.

When to seek medical help

You should seek medical advice if you have taken more than the recommended dose, or experience any signs of a serious allergic reaction after taking melatonin, like:

• swelling of the face, lips or throat
• difficulty breathing
• severe skin rash

If you feel unusually drowsy during the day, confused, or your symptoms don’t improve after taking melatonin, it’s also important to speak to a doctor or pharmacist for advice.

When not to use melatonin

Melatonin tablets are not suitable for everyone, and there are certain situations where you may be advised not to take them. For example:

• if you are allergic to melatonin or any of the other ingredients in the tablets
• if you have certain health conditions or are taking medications that could interact with melatonin

To make sure it's safe for you, tell your doctor or pharmacist before taking it if you have:

• have liver or kidney problems
• have rheumatoid arthritis, multiple sclerosis or lupus, or any other autoimmune condition

Melatonin and alcohol

It’s best to avoid drinking alcohol while taking melatonin, as it can interfere with your sleep and may reduce the effectiveness of the treatment.

Melatonin while pregnant

You should not take melatonin if you are pregnant, think you might be pregnant, or are breastfeeding, unless advised to by a doctor.

How to order your melatonin tablets with Chemist4U

Ordering with Chemist4U is easy. First, you’ll complete a short online, answering a few quick questions about your health, any medications you’re taking, and your travel plans.

Your answers are then reviewed by one our prescribing pharmacists, to check that melatonin is right for you. If approved, your melatonin tablets will be dispatched with next-day delivery, directly to your door in discreet packaging.

Storage information

Store your melatonin tablets in their original packaging in a cool, dry place out of sight and reach of children.

They should be kept below 25°C and not used after the expiry date shown on the packaging.

Alternatives to melatonin tablets

If melatonin tablets aren’t suitable for you, there are other ways to help manage jet lag while your body adjusts to a new time zone.

If getting to sleep is your main issue, over-the-counter sleep remedies, like drowsy antihistamines might help you get to sleep at night.  However, it’s important to remember that they:

• wont help you adjust to a new timezone
• can lead to grogginess the next day
• may not provide consistent results

Alongside medication, there are simple steps you can do to help your body clock settle more quickly, like:

• adjusting your sleep schedule
• getting exposure to natural light
• avoiding long daytime naps

Frequently asked questions about melatonin tablets

Can you buy melatonin in the UK?

Yes, you can get melatonin in the UK, but it can’t be purchased over the counter. Melatonin is prescription-only medicine, which means you’ll need to complete a consultation and have it approved by a prescriber before it can be supplied.

Does melatonin help you sleep?

Melatonin can help make it easier to fall asleep, especially if your sleep pattern has been disrupted, like with jet lag. It works by helping to reset your body clock, rather than acting as a strong sedative.

Is melatonin a strong sleeping pill?

No, melatonin isn’t considered a strong sleeping pill. Unlike traditional sleep medications, it doesn’t force you to sleep. Instead, it helps signal to your body that it’s time to rest, supporting a more natural sleep process.

Is melatonin legal in the UK?

Yes, melatonin is legal in the UK. It has been approved by the Medicine and Healthcare products Regulatory Agency (MHRA) and is classed as a prescription-only medicine.

This means it can only be supplied with a valid prescription and cannot be sold as an over-the-counter product or supplement.

Is melatonin bad for you?

Melatonin is generally considered safe when used as prescribed for short-term treatment.

Most people tolerate it well, although some may experience mild side effects like headache, dizziness, or daytime drowsiness.

Can someone overdose on melatonin?

It's possible to take too much melatonin. While serious problems are rare, taking more than the recommended dose can increase the risk of side effects like dizziness, drowsiness, or confusion.

Sources

• How and when to take melatonin (2023). NHS. [Accessed 17 June 2026]
• Who can and cannot take melatonin (2023). NHS. [Accessed 17 June 2026]