Does tart cherry juice help you sleep?

A little, maybe — but the evidence is thinner and more conflicted than the wellness press suggests.

The numbers, with their sample sizes attached

• +34 minutes of sleep — from a study of 20 people, over 7 days.
• 17 minutes less time awake in the night — from 15 people. Sleep latency, total sleep time and efficiency were not better than placebo.
• +84 minutes — the figure every headline quotes. It comes from eight people.

These are pilot studies, not evidence of a reliable effect.

The largest trial was null — and the cherry industry paid for it

The biggest and longest study (34 people, 14 days, a commonly sold 500 mg dose) found no effect on anything: not EEG-measured sleep, not Fitbit data, not questionnaires, not inflammation.

It was funded by the Cherry Marketing Institute. An industry-funded null result is about as credible as disconfirming evidence gets — they had every incentive to find something and didn't.

Worth knowing: much of the positive literature is also industry-funded. One of the classic positive trials was paid for "in its entirety" by the company that made the juice.

The mechanism is off by a factor of a thousand

"Cherries are a natural source of melatonin" is true and almost meaningless.

Montmorency cherries contain about 1.3 micrograms of melatonin per serving. A melatonin tablet contains 1–5 milligrams. That is roughly a thousandfold difference. You would need to drink an absurd volume of juice to approach one pill.

Whatever tart cherry does — and it may do something, via tryptophan — it is not "natural melatonin".

The honest read

There is a real signal here: a meta-analysis found objectively measured sleep efficiency and total sleep time improved. But the subjective results were null — people didn't feel like they slept better — and every trial is tiny and short.

If you like the juice, drink it; it's harmless and there might be a modest effect. Just don't expect a sleeping pill, and know you're paying a premium for micrograms of melatonin.