Every health claim on Sleep Facts is based on published research in people, linked to its source and given an evidence grade. We prefer randomised trials and systematic reviews, follow NHS and NICE guidance on treatment, check every number against its source before publishing, and correct mistakes openly.
On this page
What sources do we rely on?
We rank sources roughly like this:
- Systematic reviews and randomised controlled trials in people.
- Large long-term (cohort) studies, which can show that short sleep and a disease go together but cannot on their own prove that one causes the other. We say so whenever we use them.
- Laboratory sleep studies, such as trials that restrict people’s sleep for a few nights, which show short-term effects well but not what happens over years.
- For treatment, medicines and UK rules: NICE guidance, the NHS, the MHRA and the DVLA.
Animal studies are used only to explain why scientists think something might happen, never as evidence that it does happen in people. We don’t use manufacturers’ websites or press releases as sources for health claims.
How do we grade the evidence?
Each health claim carries one of four grades, from strong to no good evidence. The grading method is published so you can see how we decided.
How do we handle conflicts of interest?
Many studies of sleep products and supplements are paid for by the companies that sell them. That doesn’t make them wrong, but readers should know, so we mention it. The site itself takes no money, products or favours from companies that make mattresses, pillows, supplements, medicines, apps or sleep trackers.
Do we use AI?
Yes, to help search the research and draft pages. A person then checks every page against its sources: each figure, dose and finding is compared with the original before the page goes live. We never publish a claim we can’t trace to a source.
How do we keep pages current?
Every page shows when it was last updated. We review the health pages at least once a year, and sooner when an important new study or a change in NHS or NICE guidance appears.
What if we get something wrong?
We correct it, change the updated date and, if the correction changes the meaning, add a note at the end of the page saying what changed. Please report errors to hello@sleepfacts.uk, ideally with a link to the evidence.
First published 4 November 2026. Spotted an error? Tell us and we'll correct it. Read our editorial policy.