Melatonin treatment: what are the long-term effects?

Melatonin is a natural hormone produced by the pineal gland (or epiphysis) located in the centre of the brain, from its precursor tryptophan. Other organs such as the retina, the digestive system and certain blood cells also produce melatonin in smaller quantities.

In practical terms, the level of brightness perceived by our retina, the light-sensitive part of the eye, is transmitted to our hypothalamus, the part of the brain that acts as our internal clock. This small structure in the nervous system then relays the information to the pineal gland, which is responsible for secreting melatonin.

Melatonin's main role is to make us drift off to sleep after dark and to regulate our 24-hour sleep-wake cycle, also known as the circadian rhythm. Here's an overview of its functions in the human body:

1. Synchronising circadian rhythms: Melatonin helps synchronise the body's internal biological clock with the circadian rhythm, the 24-hour cycle governed by the natural alternation of light and darkness. It also plays an essential role in regulating physiological functions such as body temperature, blood pressure and the cascade of other hormones.

2. Sleep-wake alternation: Levels of melatonin, also known as the 'sleep hormone', play an important role in the transition from wakefulness to sleep and vice versa. Melatonin production increases at the end of the day, when light levels fall, signalling to the body that it is time to prepare for sleep. Its concentration in the blood is multiplied by 10 during the night, reaching its peak at around 3 or 4 in the morning before falling gently to its minimum at the moment of waking. When we get up, cortisol takes over to wake us up!

3. Antioxidant: Melatonin also acts as a powerful antioxidant in the body, helping to protect cells from damage caused by free radicals. The molecule can help protect cells from oxidative stress, boost the immune system and maintain tissue health and function.

4. Effects on mental health: Some research suggests that melatonin may have beneficial effects on mental health, particularly by helping to reduce anxiety and depression. However, research into the use of melatonin in the treatment of depression is still ongoing and there is no certainty in this area. What's more, the Anses (French National Health and Safety Agency) does not recommend melatonin as an antidepressant.

Melatonin fulfils multiple important functions in the body, from regulating sleep to modulating circadian rhythms and cell protection.

Melatonin is a hormone naturally produced by the pineal gland in the brain in response to darkness. It plays a crucial role in regulating the sleep-wake cycle, helping to synchronise the internal biological clock with the light and dark cycles of the environment. Melatonin is also available as a food supplement, offering different types of formulation to meet individual needs. There are different types of melatonin:

• Immediate-release melatonin versus sustained-release melatonin: Immediate-release melatonin is designed to be rapidly absorbed by the body, offering fast relief from sleep disturbances. In contrast, sustained-release melatonin is formulated for slow, continuous release into the body, providing support throughout the night to maintain deep, restorative sleep.

• Synthetic versus plant melatonin: Synthetic melatonin is manufactured in a laboratory using chemical processes that reproduce the molecular structure of the natural hormone. Plant melatonin, on the other hand, is extracted from plants such as brown mustard seed or rice, offering a natural, organic alternative to synthetic melatonin.

Food supplements containing melatonin should be taken in accordance with certain recommendations in terms of dosage and timing.

• 30 minutes to 1 hour before bedtime

• 0.5 mg and 5 mg per day

• 2 capsules per day of melatonin to reduce the time it takes to fall asleep

• 1 capsule per day for jet lag (at bedtime in the new time zone)

It is often advisable to start with the lowest dose and increase gradually, and only if necessary, to the maximum dose. Individual responses to melatonin may vary: the effective dose for one person may not be the same for another. A treatment of melatonin should not be taken lightly: it's best to take some time and really monitor your body's reactions, and only then make gentle, gradual adjustments.

Also read: How to take a course of melatonin?

A closer look at Natural Plant Melatonin - 60 capsules

A natural melatonin extracted from St John's Wort, with a high dose and no controversial additives, to be used as a food supplement to help you fall asleep or reduce the effects of jet lag. Essential for sleep disorders, this plant-based melatonin helps you to fall asleep without waking up the next morning feeling drowsy, and without causing any kind of dependency or addiction.

Prolonged use of melatonin is not generally dangerous, but we advise you to use it only occasionally. What's more, you should avoid creating a dependency. Once the sleep-wake balance has been restored, there is no point in continuing the treatment.

When it's time to stop taking melatonin, it's essential to proceed with caution, to talk to a healthcare professional (GP, pharmacist) and to stop taking it gradually to avoid the unpleasant symptoms that would result from stopping this supplement abruptly. A few precautions to take:

1. Consult your GP: If you have started taking melatonin for a sleep problem, talk to your doctor before stopping. He or she will be able to advise you, based on the state of your sleep and your medical history.

2. Gradually reduce the dose: If your doctor advises you to stop taking melatonin, start by reducing the amount each evening over a period of multiple days/weeks, until you no longer need it. This allows your body to adapt gradually to the reduction to the natural level of melatonin, whereas stopping too abruptly could cause real difficulties in falling asleep.

3. Monitor your symptoms: While you're reducing or stopping melatonin, monitor the quality of your sleep, bearing in mind that your body needs time to readjust. That said, if your sleep problems persist for a few weeks after stopping treatment, feel free to consult a healthcare professional.

4. At the same time, try other natural solutions: As you gradually lower your melatonin levels, it's a good idea to explore other techniques and solutions for improving the quality of your sleep, such as aromatherapy, relaxation exercises, regular physical exercise, a consistent sleep routine, and creating a sleep-friendly environment in your bedroom.

Drowsiness, nightmares, digestive problems... What are the side effects of melatonin?

Consumption of this compound is not harmless, which is why it may be advisable to consult your GP before taking it. Studies have shown that it can cause certain physical and psychological side-effects, which vary according to individual sensitivity and the dose ingested:

• Drowsiness

• Headaches

• Dizziness

• Nightmares

• Nausea, vomiting

• Constipation

• Agitation, irritability

• Anxiety and depressive disorders

To avoid these side effects, make sure you take the recommended doses. If you experience excessive discomfort, feel free to pause your treatment.

Are there any dangers to taking melatonin every day?

Unlike sleeping pills, melatonin has few side effects or habit-forming effects. While some people may experience undesirable side-effects such as migraines, nausea, dizziness or episodes of drowsiness, particularly when taking the wrong dosage, there is no particular danger in taking melatonin every day.

However, it should be remembered that this supplementation serves above all to stabilise the circadian cycle. If you have regained a proper alternation between waking and sleeping, whether to avoid falling asleep too late, to remedy jet lag or if you suffer from sleep disorders, there is no point in continuing your melatonin treatment.

What's more, if you suffer from nervousness, anxiety or depression, it's best to turn to natural solutions such as herbal teas, essential oils or CBD oil.

Contraindications to melatonin

According to ANSES (Agence Nationale Sanitaire Alimentaire; French Agency for Food, Environmental and Occupational Health & Safety), the use of melatonin is not recommended for certain categories of people:

• Children and adolescents: Research is still exploring the possible neurological consequences of melatonin consumption in children and adolescents.

• Pregnant and breastfeeding women: Pregnant or breastfeeding women can turn to other natural methods to help them sleep if they feel the need (e.g. infusions, hydrosols). If you're looking for ways to combat insomnia during pregnancy and/or breastfeeding, take a look at our article: Which Aroma-Zone products should you use or avoid during pregnancy?

• People who drive or use machinery: As melatonin can make you drowsy during the day, it is important to exercise caution and avoid activities such as driving, using heavy machinery or engaging in risky activities.

• People suffering from conditions such as inflammatory or auto-immune diseases, epilepsy, asthma, mood, behavioural or personality disorders.

• People taking medication: Melatonin consumption may interact with certain drugs such as contraceptives, antidepressants, anticoagulants, and anti-diabetics. If you are taking any kind of treatment, always ask your doctor for advice to avoid these interactions.

Is it dangerous to take melatonin every day?

Melatonin may be suitable for people with episodic sleep problems who need a one-off boost. If you wish to undertake a long-term course of treatment, it is best to consult a healthcare professional to discuss the matter and determine the appropriate dose and course duration.

Is melatonin addictive?

Melatonin supplements are unlikely to cause physical dependence as such, but some users may develop a tolerance to their soporific effects. This means that an initial dose may become less effective over time, but the dependence is much less than the addictive effects of drugs such as sleeping pills.

After graduating from ESCP Business School in 2020, Louise began her career as a writer in 2021. Today, she writes a newsletter in which she shares cultural recommendations, as well as more personal articles, such as dating apps, therapy and career guidance. She also writes for the media, brands and agencies on subjects such as well-being, mental health, culture, and society.