The short answer
Most sleep aids sold in the UK have only weak evidence: magnesium, valerian, chamomile, lavender and sedating antihistamines such as Nytol help little, if at all, in trials. Melatonin shortens the time to fall asleep by about 7 minutes and works better for jet lag. Prescription sleeping pills work in the short term but carry real risks. For long-term insomnia, CBT for insomnia beats all of them.
On this page
Which sleep aids work?
We grade how good the evidence is that each one improves sleep, using our four grades. A high grade means the effect is well proven, not that the aid is safe or right for you.
| Sleep aid | Grade | What the studies show |
|---|---|---|
| CBT for insomnia (not a pill, for comparison) | Strong | A review of 20 trials found people fell asleep about 19 minutes faster and spent 26 fewer minutes awake at night, with benefits that last. |
| Prescription sleeping pills | Strong | They work in the short term: in older people they added about 25 minutes of sleep, but with nearly five times the risk of memory and thinking side effects. |
| Melatonin | Moderate | A review of 19 studies found people fell asleep 7 minutes faster and slept 8 minutes longer. It helps more with jet lag. |
| Magnesium | Weak | Three small trials in older adults suggest people may fall asleep a little faster. The evidence is low quality. |
| Valerian | Weak | Results are mixed. A review of 18 trials found no measurable difference in time to fall asleep. |
| Chamomile | Weak | Small trials suggest better sleep quality, but a trial in people with insomnia found no clear benefit. |
| Lavender | Weak | Lavender oil capsules eased anxiety and restless sleep in one trial. Evidence for sleep on its own is thin. |
| Weighted blankets | Weak | One trial in psychiatric patients found a large improvement in insomnia. It has not been repeated. |
| Nytol and other antihistamines | Weak | Small, short-lived effects, with next-day drowsiness. US guidelines advise against them for insomnia. |
How should you choose?
Start with the cause. A few bad nights after stress, travel or illness usually settle on their own, and good sleep habits help. If you’ve slept badly on most nights for three months, that is insomnia, and NICE recommends CBT for insomnia first, before any pill.
If you do want to try something:
- Ask a pharmacist. They can check what you already take, and many sleep aids interact with alcohol, antidepressants, painkillers and other sedatives.
- Use it for a short time. Most sleep aids are meant for days or a few weeks, not months.
- Don’t combine sedatives. Mixing herbal remedies, antihistamines, sleeping pills, melatonin or alcohol increases drowsiness and the risk of falls.
- Take care the next day. Several leave you drowsy in the morning, which matters if you drive.
Why do sleep aids seem to work better than trials show?
Insomnia often improves on its own, and the placebo response in sleep trials is large: people given a dummy pill often report sleeping better too. So a remedy can feel like it works when most of the change would have happened anyway. That is why we rely on randomised trials that compare each aid with a placebo.
What about the rules in the UK?
Melatonin and sleeping pills are prescription-only medicines in the UK. Sedating antihistamines such as Nytol and Sominex are sold in pharmacies. Herbal remedies may carry a THR mark (traditional herbal registration), which means the product meets quality and safety standards, but its use is based on tradition, not on proof that it works. Supplements such as magnesium are sold as food and don’t need to prove they work at all.
In this section
- Melatonin for sleep: does it work, and can you get it in the UK?
What melatonin does, how much it helps sleep and jet lag in trials, why it is prescription only in the UK, and the problem with supplements bought online.
Moderate - Magnesium for sleep: does it help?
What the trials show about magnesium supplements and sleep, which people might benefit, safe doses in the UK, and who should avoid it.
Weak - Valerian for sleep: what the trials show
Does valerian root help you sleep? What reviews of the trials found, how it compares with Nytol, UK herbal products, side effects and who should avoid it.
Weak - Chamomile tea for sleep: does it help?
Does chamomile help you sleep? What trials of chamomile tea and extract show for sleep quality and insomnia, and who should be careful with it.
Weak - Lavender for sleep: oil, pillow sprays and capsules
Does lavender help you sleep? What trials of lavender oil capsules and lavender scent found, how big the effects are, and what to watch out for.
Weak - Nytol and other sleep antihistamines: do they work?
How sedating antihistamines such as Nytol (diphenhydramine) and Sominex or Phenergan (promethazine) affect sleep, how well they work, and the risks.
Weak - Sleeping pills in the UK: zopiclone, zolpidem and newer options
How prescription sleeping pills such as zopiclone, zolpidem, temazepam and daridorexant work, how much they help, the risks and when GPs prescribe them.
Strong - Weighted blankets for sleep: what the evidence shows
Do weighted blankets help you sleep? What the main trial found, who it applies to, how heavy a blanket should be, and who shouldn't use one.
Weak
Common questions
What is the best sleep aid in the UK?
For insomnia that has lasted months, the best-proven treatment is not a pill but CBT for insomnia, which NICE recommends first and the NHS offers as the Sleepio app in many areas. For a short bad patch, a pharmacist can advise on short-term options. No supplement has strong evidence behind it.
Can I buy melatonin in the UK?
Not over the counter. In the UK melatonin is a prescription-only medicine, mainly prescribed for short-term use in people aged 55 and over. Melatonin bought online from abroad is unregulated, and tests of supplements have found the dose on the label is often wrong.
Are herbal sleep remedies safe?
Most are low risk for healthy adults in short courses, but not risk free. Don't combine them with alcohol, sleeping pills or melatonin, and check with a pharmacist first if you are pregnant, breastfeeding, take other medicines or have liver disease.
References
- Sateia MJ et al. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: an American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine, 2017.pubmed.ncbi.nlm.nih.gov
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One, 2013.pubmed.ncbi.nlm.nih.gov
- Trauer JM et al. Cognitive behavioral therapy for chronic insomnia: a systematic review and meta-analysis. Annals of Internal Medicine, 2015.pubmed.ncbi.nlm.nih.gov
- NICE. Sleepio to treat insomnia and insomnia symptoms (MTG70), 2022.nice.org.uk
- NHS. Melatonin.nhs.uk
First published 4 November 2026. Spotted an error? Tell us and we'll correct it. Read our editorial policy.