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Melatonin is your body’s built-in sleep signal - the hormone that tells you when it’s time to wind down. But screens, artificial light, and even changing seasons can throw it off balance. Learn how melatonin works, what disrupts it, and how to help your body find its natural rhythm for deeper, more restorative sleep.
8 Min Read | By Nat Took
Last Modified 14 October 2025 First Added 21 July 2020
Review for Accuracy by Dr Jason Ellis
Often called the “sleep hormone”, melatonin helps your body know when it’s time to rest and when it’s time to wake. But with artificial light, late-night screen time, and busy modern routines, our melatonin levels can easily fall out of sync. In this guide, we’ll explain what melatonin is, how it works, and how to naturally support your body’s sleep rhythm, as well as how to use melatonin supplements for better sleep.
Melatonin is a naturally occurring hormone produced mainly by the pineal gland – a small, pea-shaped structure deep within the brain. Often called the “sleep hormone,” it helps regulate your circadian rhythm – the internal clock that tells your body when it’s time to sleep and wake up. Levels of melatonin naturally rise in the evening as light fades, helping you feel drowsy, and drop again in the morning as daylight returns.
Melatonin’s release is closely tied to light and darkness – it’s your body’s natural cue that night has arrived. As the sun sets and daylight decreases, your eyes detect the drop in light and send a signal to the brain’s pineal gland to begin releasing melatonin. This rise in melatonin acts like a biological “dimmer switch,” gently slowing your heart rate, lowering your body temperature, and helping your mind relax – all signals that prepare you for sleep. It doesn’t put you to sleep instantly, but rather creates the right internal conditions for sleep to come naturally.
On the other hand, exposure to bright light, especially from screens or overhead lighting in the evening, suppresses melatonin production, keeping your body in “daytime mode” and making it harder to drift off. This delicate rhythm is what keeps your sleep–wake cycle aligned with natural day and light patterns.
If you’re having difficulty sleeping, it could be due to your exposure to light, which confuses your signalling system. Jason Piper, a certified sleep coach and founder of Build Better Sleep, told us:
Melatonin is also known as the “Dracula hormone” because it only comes out at night. It is produced in the pineal gland and released when it is dark out. It helps us to feel sleepy, entrain our circadian rhythm, and is the body’s strongest antioxidant.
The body has natural rhythms that wake us up and put us to sleep. This is very useful. In the morning, our cortisol levels naturally rise to wake us up and prime us for the day. Cortisol is useful in the morning as it makes us alert, clear-thinking, and gives us energy. At night, as the sun sets, our eyes register the changing light and melatonin is released so that we feel sleepy, so we can rest and repair the body overnight.
If you think back to a time before electricity, this worked perfectly. We were up at daylight to hunt, farm, and gather. All of the day’s activities were done during daylight hours, and then nighttime was dedicated to sleeping.
Fast forward to today, and most of us are living disconnected from our biological clocks, and this is wreaking havoc on our bodies. We wake up and head off to spend most of the day inside a building under dim lighting, compared to the sun. We then come home and turn on bright lights, compared to what’s outside when it’s dark. This action tells the body it’s still daytime. This is why a number of people are having a hard time falling asleep. They are sending mixed signals to their brain.
As our sleep is naturally regulated by the rhythm of day and night, it makes sense that modern life, with its constant light, noise, and stimulation, can sometimes throw that off balance. Blue light from screens and some light bulbs is one of the biggest disruptors, but it’s not the only factor that can affect how your body produces and releases melatonin. If you’re looking to support your natural sleep–wake cycle and encourage healthy melatonin levels, try the following:
1. Reduce blue light exposure in the evening: Light from phones, tablets, and TVs tricks your brain into thinking it’s still daytime, suppressing melatonin production. Dimming lights and switching off screens at least an hour before bed helps your body recognise that it’s time to wind down.
Learn more about how screens and scrolling on social media affect sleep.
2. Increase your exposure to natural daylight: Getting outside during the day, even for a short walk, helps regulate your internal body clock. Natural light exposure in the morning boosts alertness and ensures melatonin production kicks in naturally as evening approaches.
3. Reduce your caffeine intake later in the day: Caffeine blocks the receptors in your brain that make you feel sleepy, delaying melatonin’s effects. Avoiding coffee, tea, and energy drinks in the afternoon can help your body produce melatonin at the right time.
Discover some alternative bedtime drinks that won’t disrupt your sleep on the Sleep Matters Club.
4. Have consistent bed and waking times: Going to bed and waking up at the same time each day reinforces your circadian rhythm. A consistent routine helps your body learn when to release melatonin and when to stop, making it easier to fall and stay asleep. Use our Sleep Calculator to find out the perfect bedtime and wake-up time for you.
5. Minimise noise and light in the bedroom: A dark, quiet room sends a clear signal to your brain that it’s night-time. Using blackout curtains or an eye mask and blocking out noise helps maintain melatonin production through the night for deeper, more restful sleep.
Dr Bay Kelly offers their advice on how to naturally support melatonin production:
Melatonin is produced by transforming an amino acid called tryptophan, meaning that dietary factors can affect melatonin production. Tryptophan can be found in foods such as chicken, dairy products, eggs, spinach, nuts, seeds and salmon. It’s also important to know that in order for your body to produce sufficient amounts of melatonin from tryptophan, sufficient amounts of zinc, B6 and magnesium are needed.
Read our edit of the best foods that help you sleep.
If you’re struggling to fall asleep or stay asleep, melatonin supplements might seem like an easy solution to help reset your body clock. In the UK, melatonin is available only on prescription, typically for short-term use and most often to manage sleep disruption caused by jet lag or shift work. Melatonin supplements work by mimicking the hormone your body naturally produces at night, helping signal that it’s time to rest. While some studies suggest it can be effective in improving sleep onset and regulating the body clock, others find little to no benefit, and results can vary widely from person to person. According to Dr Kelly, doses between 1–5 mg have shown promise for those whose sleep is affected by irregular schedules, such as travellers or night-shift workers. However, for long-term sleep difficulties, it’s best to speak with your GP, as there may be underlying causes that need a more tailored approach than supplements alone.
While we know the importance of natural melatonin for the body and various bodily functions, the impact of synthetic melatonin is less well understood. However, melatonin has shown greater than placebo effects for a variety of sleep-related issues, including the onset of sleep, total sleep duration and sleep efficiency.
Evidence of efficacy has led to the use of melatonin for the following conditions:
The amount of melatonin you need can vary depending on why you’re taking it and how your body responds. In general, studies suggest that a low dose, typically between 1–5 mg, is enough to help support sleep for most adults. Taking more won’t necessarily make you sleep better and may even have the opposite effect, leaving you groggy the next day. Because melatonin is a hormone, it’s best to start with the lowest possible dose and only use it under medical guidance. In the UK, melatonin is prescription-only, so your GP will determine the right dosage and timing based on your individual needs.
Melatonin doesn’t act like a sleeping pill that “knocks you out”. Instead, it helps your body prepare for sleep. Its effects usually begin around 20-40 minutes after taking it, helping you fall asleep more easily by calming your body and signalling that it’s time to rest. Most people find that melatonin supports a full night’s sleep of around 7 to 8 hours, though the duration can vary depending on dosage, timing, and your body’s natural rhythm. Because it helps regulate rather than induce sleep, melatonin is best used to restore balance to your sleep–wake cycle rather than as a nightly quick fix.
Timing is key when it comes to melatonin. It’s usually most effective when taken 20-40 minutes before bed, giving your body time to respond as natural melatonin levels start to rise. If you’re using it to manage jet lag or adjust to shift work, the timing might differ slightly. Your GP can advise on the best schedule to help reset your internal body clock.
Melatonin isn’t routinely recommended for children, and it should only ever be used under medical supervision. In some cases, doctors may prescribe it for children who have specific sleep disorders or conditions that affect their sleep patterns. However, for most children, building healthy sleep habits, like consistent bedtimes, calming bedtime routines, and reduced screen time before bed, is a safer and more effective way to improve sleep. If your child regularly struggles to fall asleep, it’s best to speak to a GP or paediatric sleep specialist before considering melatonin.
Beyond its well-known connection to sleep, melatonin has several other fascinating functions. It helps the body adapt to seasonal changes – influencing rhythms such as mood, metabolism, and temperature regulation – and even plays a part in certain animal and plant processes, from hibernation to protection against oxidative stress. In humans, melatonin acts as a powerful antioxidant, defending cells against damage from free radicals and supporting immune health. Research also links declining melatonin levels with ageing, suggesting its antioxidant and immune-modulating properties may help protect against some age-related diseases. It has also been found to reduce anxiety in patients prior to surgery, highlighting its ability to calm the mind and body. While its broader health benefits are still being explored, there’s no doubt that melatonin is more than just a sleep hormone.
Melatonin isn’t technically banned in the UK, but it is classed as a prescription-only medicine, meaning you can’t legally buy it over the counter as you can in some other countries. This regulation exists because melatonin is a hormone that affects your body’s internal clock, and its long-term effects aren’t fully understood. By keeping it prescription-only, UK health authorities ensure it’s used safely and appropriately, usually for short-term treatment of sleep problems, under a doctor’s guidance. In contrast, countries like the US allow melatonin to be sold as a supplement, but this also means it isn’t as tightly regulated. So, while you can’t pick it up freely in UK shops, this restriction helps protect people from potential misuse and ensures the right dose and timing are prescribed for each individual.
Melatonin is generally considered safe, with fewer side effects than other sleeping medicines. If you experience any melatonin side effects, such as adverse reactions or changes to how you normally feel, contact your doctor as soon as possible.
It’s also important to note that melatonin can cause issues if you’re taking other medicines, such as birth control and diabetes drugs.
Melatonin helps keep your body in tune with the natural rhythm of day and night, preparing you to rest and recharge. While supplements can be useful for short-term issues like jet lag, the best way to support healthy levels is through good habits like getting natural daylight, limiting screens before bed, and keeping a consistent sleep routine. Think of melatonin as your body’s gentle cue to unwind; by supporting it naturally, you’ll set yourself up for deeper, more restorative sleep.
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