Melatonin and ADHD: Why Sleep Can Be So Difficult
You’re exhausted all day. You drag yourself round work, struggling to focus or concentrate, and spend most of the day looking forward to bed that night. Tonight will be different, you tell yourself. Tonight you’ll have an early night and finally catch up.
Then bedtime arrives, and suddenly you’re wide awake. Your brain’s buzzing, and it feels like the perfect time to start a project or tackle the job you’ve been putting off for weeks. Before you know it, half the night’s gone.
The next morning you’re shattered again, and the whole cycle starts over. Exhausted when you need to be awake, and wide awake when you need to be asleep.
If you’ve got ADHD, this might be about more than a busy brain or poor sleep habits. Your body clock could be part of the picture.
Why is sleep so hard with ADHD?
It’s often hard to work out what’s causing poor sleep, as there’s usually more than one thing going on.
Your body clock might run later than other people’s. Your brain might struggle to switch off once the day’s distractions stop. Hyperfocus and time blindness mean 10pm can turn into 1am before you’ve even noticed. The moment your head hits the pillow, the overthinking starts, going over the day, worrying about tomorrow and replaying conversations. ADHD medication can make it harder to fall asleep for some people, while for others it actually helps.
What is melatonin?
Melatonin is a hormone that tells your body biological night is starting. It’s made mainly in the pineal gland, a small gland deep in your brain.
The pineal gland takes its cue from your body’s master clock, a tiny area in the brain that reads information about light coming in through your eyes. As it gets dark, melatonin rises. In the morning, it falls.
Melatonin is often called the sleep hormone, which is a bit misleading. It doesn’t knock you out like a sedative. It’s more like the dimmer switch that tells your body it’s nearly bedtime. That’s why being tired and being ready to sleep aren’t the same thing.
What does a delayed body clock mean?
With ADHD, your internal clock can run much later than the world around you. Research has found links between ADHD and a delayed body clock, including melatonin starting to rise later in the evening (Snitselaar et al., 2017).
Imagine being expected to fall asleep at 10pm when your body isn’t ready until midnight or later. You can be exhausted and desperate for sleep, and still lie there wide awake.
This doesn’t mean everyone with ADHD has a delayed body clock. It also doesn’t mean people with ADHD don’t make enough melatonin. The evidence points to a difference in timing in some people, not a lack of the hormone.
Is it insomnia or a body clock problem?
Often, it’s both.
ADHD itself can cause a racing mind at bedtime. Your brain’s thinking about a million things at once, replaying the day and planning tomorrow, and it just won’t switch off. That’s real, and it can keep you awake whatever time your body clock is set to.
On top of that, there can be a body clock problem too. Most sleep advice and treatment is built for insomnia, so if your body clock runs late as well, you can follow all the advice perfectly, with early nights, no phone and a warm bath, and still be lying awake at 1am.
It matters for melatonin too. Melatonin isn’t usually recommended for insomnia, and that makes sense, as most insomnia isn’t caused by a problem with melatonin. With ADHD, though, part of the problem can be when our melatonin is released, and timing is exactly what melatonin works on.
Does melatonin help people with ADHD?
There’s some promising evidence. In a small trial of 51 adults with ADHD and a delayed body clock, a low dose of melatonin moved their body clock earlier by around an hour and a half, and their ADHD symptoms reduced by 14% (van Andel et al., 2021).
A follow up analysis found that melatonin on its own wasn’t enough to move their actual sleep times earlier. The researchers said behavioural support was needed alongside it (van Andel et al., 2022).
So melatonin isn’t a treatment for ADHD, and it won’t fix every sleep problem. For people whose body clock runs late, though, it may help, especially alongside other support.
Is melatonin safe?
In the short term, it looks very safe. A systematic review found that side effects were few and generally mild, and most cleared up within a few days or as soon as people stopped taking it. The same review said there isn’t yet enough long term research to be certain about taking it for years (Besag et al., 2019).
In the UK, the licensed melatonin tablet for adults is usually prescribed for up to 13 weeks, with regular reviews along the way (NHS Lanarkshire, 2021). You’ll often hear that you need to have a break from melatonin because your body gets used to it, but there isn’t good evidence for that. The 13 week limit is down to how long the tablet was tested for in trials. When breaks are suggested, it’s usually to check whether you still need it, rather than because it’s stopped working.
Sleeping tablets work differently. Whether they’re antihistamines from the chemist or tablets from your GP, they can knock you out, but being sedated isn’t the same as natural, restful sleep. That’s why you can still wake up feeling like you’ve been hit by a bus, and they don’t change the timing of your body clock either.
Why is melatonin so hard to get in the UK?
In the UK, melatonin is a prescription only medicine, and you can’t legally buy it as an ordinary supplement (NHS, n.d.). It’s sold as a supplement in some countries, like the US, but the NHS advises against buying it online, as products may not contain what they say or the dose they claim.
The licensed products only cover certain groups. The prolonged release tablet Circadin is licensed for short term insomnia in adults aged 55 and over. Some other melatonin products are licensed for children, including children with ADHD. There’s no licensed melatonin product for adults with ADHD and a delayed body clock.
NICE looked at the evidence on melatonin and ADHD in 2021, and decided there wasn’t enough to change its ADHD guideline (NICE, 2021).
That means if a GP prescribes melatonin for an adult with ADHD, it’s usually off licence. In the UK, that’s allowed, but the prescriber takes on more personal responsibility for the decision. Many GPs are cautious about this, and local NHS prescribing rules can limit what they’re able to prescribe. Some will want a specialist to recommend it first.
So if your GP says no, it’s not necessarily that they don’t believe you. They’re working within rules that weren’t written with ADHD body clocks in mind.
Should there be a different approach?
When someone with ADHD comes in with sleep problems, a few extra questions could make a real difference:
Have you always been a night owl, even as a child?
When you’re free, on holiday or at the weekend, what time does your body naturally want to sleep and wake up?
If you could sleep at that time, would you sleep well?
If the answers point to a late body clock rather than insomnia, the support can be very different. This isn’t about anyone getting it wrong. It’s about making sure the right problem gets treated.
ADHD, perimenopause and sleep
For women with ADHD, perimenopause can make sleep even harder. Night sweats, hot flushes, anxiety and low mood can all disrupt sleep, on top of any body clock issues you already had.
Sleep apnoea can also play a part. It becomes more common after menopause, and it’s often missed in women, as it can show up as tiredness, poor sleep or low mood rather than loud snoring. A European study of women aged 40 to 67 found that those with lower oestrogen and progesterone levels were more likely to snore and report symptoms of sleep apnoea (Sigurðardóttir et al., 2022).
Melatonin won’t help with night sweats or sleep apnoea, so if your sleep has changed, talk to your GP about the whole picture.
What can help?
Rule out other causes first. Not every sleep problem is about ADHD or your body clock. Sleep apnoea, restless legs, low iron, thyroid problems, low vitamin D, pain, night sweats and medication can all play a part, so ask your GP about blood tests too. Signs of sleep apnoea include snoring, waking up gasping or choking, morning headaches, feeling exhausted however long you sleep, or a partner noticing you stop breathing in your sleep. If any of that sounds familiar, speak to your GP, as you may need a referral to your local sleep service.
Keep track of your sleep. It doesn’t have to be a proper sleep diary. A quick voice note in the morning, a photo of the clock when you finally start to feel sleepy, or the sleep data from your phone or smartwatch all help. If you’re regularly not falling asleep until 1 or 2am however hard you try, that’s really useful for your GP to know, as it can help them work out whether your body clock is part of the problem.
Get some daylight in the morning. Getting outside first thing, even for a short while, helps set your body clock earlier, so you start to feel sleepy earlier in the evening. At night, bright lights and screens can hold back your melatonin, so switching the big lights off and using lamps later in the evening can help.
Give yourself a nudge to start getting ready for bed. With ADHD, stopping what you’re doing is often the hardest part. Setting an alarm to remind you it’s time to start winding down, and deciding on a time after which you won’t start anything new, can stop 10pm turning into 1am.
Look at what else might be affecting your sleep. Caffeine can stay in your system for hours, so a coffee mid afternoon could still be keeping you awake at bedtime. Alcohol might help you drop off, but it tends to wake you up later in the night. If you take stimulant ADHD medication, taking it later in the day can make it harder to sleep, so talk to your prescriber about the timing rather than changing it yourself. Pain, night sweats and restless legs, that urge to keep moving your legs in the evening, can all keep you awake too.
When you feel tired all day and awake half the night, just remember that this cycle might have nothing to do with willpower or trying harder. It could be a body clock that’s set to a completely different time zone, and understanding that could be the first step to getting the right help.
References
Besag, F.M.C., Vasey, M.J., Lao, K.S.J. and Wong, I.C.K. (2019) ‘Adverse events associated with melatonin for the treatment of primary or secondary sleep disorders: a systematic review’, CNS Drugs, 33, pp. 1167–1186. doi: 10.1007/s40263-019-00680-w.
National Institute for Health and Care Excellence (2021) 2021 exceptional surveillance of attention deficit hyperactivity disorder: diagnosis and management (NICE guideline NG87). Available at: https://www.nice.org.uk/guidance/ng87/evidence/2021-exceptional-surveillance-of-attention-deficit-hyperactivity-disorder-diagnosis-and-management-nice-guideline-ng87-10892592253 (Accessed: 20 October 2026).
NHS (n.d.) Common questions about melatonin. Available at: https://www.nhs.uk/medicines/melatonin/common-questions-about-melatonin/ (Accessed: 20 October 2026).
NHS Lanarkshire (2021) Guideline on the use of melatonin for the management of sleep disorders. Available at: https://rightdecisions.scot.nhs.uk/media/1885/guideline-on-the-use-of-melatonin-for-the-management-of-sleep-disorders-20211117-v2.pdf (Accessed: 21 October 2026).
Sigurðardóttir, E.S. et al. (2022) ‘Female sex hormones and symptoms of obstructive sleep apnea in European women of a population-based cohort’, PLoS One, 17(6), e0269569.
Snitselaar, M.A., Smits, M.G., van der Heijden, K.B. and Spijker, J. (2017) ‘Sleep and circadian rhythmicity in adult ADHD and the effect of stimulants: a review of the current literature’, Journal of Attention Disorders, 21(1), pp. 14–26. doi: 10.1177/1087054713479663.
van Andel, E., Bijlenga, D., Vogel, S.W.N., Beekman, A.T.F. and Kooij, J.J.S. (2021) ‘Effects of chronotherapy on circadian rhythm and ADHD symptoms in adults with attention-deficit/hyperactivity disorder and delayed sleep phase syndrome: a randomized clinical trial’, Chronobiology International, 38(2), pp. 260–269. doi: 10.1080/07420528.2020.1835943.
van Andel, E. et al. (2022) ‘Attention-deficit/hyperactivity disorder and delayed sleep phase syndrome in adults: a randomized clinical trial on the effects of chronotherapy on sleep’, Journal of Biological Rhythms. doi: 10.1177/07487304221124659.
Medical disclaimer
This blog is for information and education and is not a substitute for individual medical advice. Melatonin is a prescription only medicine in the UK. Discuss persistent sleep difficulties and any medication questions with an appropriate healthcare professional.
