Circadin is a medicine that is synthetically produced by the hormone melatonin. The hormone is found naturally in the body and helps regulate our sleep patterns. The drug has had particularly good results in treating jet lag that can occur when flying over several time zones. It is a prescription drug that can only be prescribed by a doctor.

If you are travelling far and would like to avoid major plagues with jet lag, Circadin may be an option. Here you will find more information about the treatment.1

What’s on this page:

How does Circadin work?

To understand how Circadin works, we must first investigate the role of melatonin in the brain.

Melatonin is a natural hormone in the body that is formed in the retina of the eye as well as in the pineal gland of the brain. It is formed especially in the evening and at night when it is dark outside. It makes you sleepy, so you can have a good night’s sleep. The hormone is, therefore, an important piece in our so-called inner clock, that is, the rhythm that the body has in relation to the day’s waking and sleeping hours.

When we fly over several time zones, this internal clock is disturbed. Suddenly, we’ll either be tired “before bedtime” or it keeps us awake much longer than usual in order to adapt to the new time zone. This can cause jet lag. The new daily rhythm may interfere with the body’s natural secretion of melatonin at the time point where it is needed.

Circadin enters and affects the daily rhythm and sleep by giving the hormone melatonin a supplement. Taking it a couple of hours before going to bed can help bring the body into a good rhythm in the new time zone.

Circadin 2mg – How do you use the treatment?

Circadin is available as a prolonged-release tablet where a tablet contains 2 mg melatonin. The tablets should be swallowed whole and must not be crushed, divided or chewed. They should be taken after a meal or with some snacks.

The tablet should be taken 1-2 hours before going to bed. That is if you arrive at the new time zone in the afternoon and you usually go to sleep at 22.00, then you will take a tablet at around 20.00 o’clock. The melatonin hormone will then start to prepare your body for sleep.

The melatonin has its strongest effect after 30 minutes to 2 hours after ingestion. However, it can vary from person to person, how quickly it affects the body.

The treatment is meant as a short-term treatment of sleep disorders and is therefore not a drug to be taken over a long period of time. However, it can be taken for a period of up to 13 weeks.

Possible side effects

Since the hormone in the tablets is also naturally in the body, few are experiencing problems with them. However, this is individual and therefore it is important to be aware of the possible side effects.

The most common side effects when using Circadin are:

Abdominal pain Elevated blood pressure Anxiety Dizziness
migraine hyperactivity Inflammation of the skin Liver Effects

1 out of 100 will statistically experience these effects to a mild or severe degree.

Very rare side effects may include:

  • Cardiac cramps
  • Depression
  • Confusion

Always read the instructions before starting any treatment and contact a doctor if you experience any unpleasant side effects.

What should you be aware of?

When taking Circadin you should be aware of the following:

  • The treatment should not be used if you have a low liver function
  • It should not be used if you are planning to drive a car or operate large machines
  • It can have an enhancing effect on other sleeping pills and tranquillizers
  • Do not ingest alcohol before, during or after ingestion of the tablets
  • It should also not be taken with Fluvoxamine which is used against depression. Always inform your doctor about the other medicines you are using at the time
  • Pregnant or breastfeeding women should avoid the treatment because there is not enough research on this matter yet
  • Do not take medicine if you are allergic to the ingredients

When can you consider using this treatment?

Medicines that contain melatonin have documented the effect of sleep disturbances, especially for jet lag. It has shown a particular ability to travel eastwards where you should speed up your sleep because the day becomes shorter when you travel eastward. For example, from Europe to China, Thailand or India.

You should consider the medicine especially if you are going on a business trip or if you are an athlete when you need to perform, because in these cases it may be extra important to get a good night’s sleep.

Can I buy Circadin online in the UK?

If you are going to travel and want to avoid the worst jet lag symptoms, you can get a prescription for the treatment. You can get it from your own doctor or at an approved online clinic. In the case of the latter you answer simple questions about your health and if the doctor approves the treatment, you will receive a prescription online. Then it will be sent to you by post.

If you need the product for any other sleep disorder, such as sleeplessness, always go to your GP. It is important to check what your sleep problems are deriving from in order to receive the right treatment.


  1. Tired after travelling? – NHS