SubEx

Myth check

Benadryl for sleep: you feel it working, the recordings don't show it

People said they slept better; the electrodes showed no change. And in fifteen healthy men, its daytime drowsiness had worn off by day four.

Diphenhydramine

Diphenhydramine, the drug in Benadryl, gets used as the mild way to knock yourself out. Over two weeks, adults with mild insomnia said they slept better on it, while the electrodes on the same nights found no difference, in a trial built to catch the diary change. In fifteen healthy men taking it twice a day, the drowsiness had worn off by day four. It can feel like sleep help without the recordings picking it up, and the sedation it is taken for can fade within days.

The findings behind this

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SleepPeople said they slept better; the electrodes showed no change

In 184 adults with mild insomnia, 50 mg at bedtime raised self-reported sleep efficiency over two weeks. The same nights' recordings found no difference on any sleep measure.

★★★Well replicated — this finding’s sources average out to meta-analyses, systematic reviews or high-powered trials.The trial was powered on the diary outcome, so a flat recording is a difference not detected rather than a difference shown to be absent. Mild insomnia in adults averaging 44, not the older people the warnings are about. The drug arm ran 14 nights, so nothing here reaches beyond a fortnight.Click to keep this openSleep betterDiphenhydramine
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SleepThe sedation had worn off by day four, in fifteen healthy men

On 50 mg of diphenhydramine twice daily, fifteen men were measurably sleepier than on placebo on day one and indistinguishable from it by day four.

★★☆Single study — solid evidence, such as one good trial or a large observational dataset, but not replicated at the top tier.Fifteen healthy men, no women, nobody with a sleep problem. The dosing was twice daily and the outcome was daytime sleepiness, so a nightly bedtime habit is an inference rather than something this trial watched. Four days shows tolerance arriving and says nothing about weeks.Click to keep this openSleep betterDiphenhydramine

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