Hops

Nathalie Schicktanz et al. (2025) · Brain and behavior

This randomized, double-blind, placebo-controlled trial with 40 completers explored whether Ze 91019, a fixed extract combination of valerian root (Valeriana officinalis) and hops (Humulus lupulus), could improve sleep in adults with occasional insomnia — sleep disturbances happening once or twice a week rather than a full clinical insomnia diagnosis — without the grogginess or memory problems that often accompany prescription sleep medications like benzodiazepines. Valerian and hops are long-used botanical sleep aids; in this fixed combination they are thought to act on the brain's adenosine system, the same pathway caffeine blocks, which governs how sleepy or alert the brain feels. Forty-one healthy adults aged 18-65 with occasional sleep problems and subjective cognitive complaints were randomized at the University of Basel, Switzerland, to either Ze 91019 or placebo for 21 nights, after a 21-day baseline period. Each night, participants took one tablet, 500 mg valerian extract plus 120 mg hops extract, about an hour before bed. A Fitbit Charge 5 wristband tracked sleep duration and heart rate continuously, while daily online tests measured reaction time and working memory (digit span backward), and visual analog scales captured mood, stress, tiredness, and sleep quality. The study design itself worked well, with adherence above 89% for surveys and medication and above 96% for the wearable tracker. Compared with placebo, Ze 91019 increased average nightly sleep duration by 21.7 minutes (p = 0.019, a small-to-moderate effect) and lengthened time in bed by 24.4 minutes (p = 0.023). The benefit was largest on each person's shortest night of sleep, where Ze 91019 added 48.7 minutes of sleep versus placebo (p = 0.016), suggesting the extract may help most when sleep is already restricted. Despite the sleep gains, daytime reaction time, working memory, and self-rated mood, stress, and cognitive performance did not differ significantly between groups (p ≥ 0.26), meaning the extra sleep did not translate into measurable next-day cognitive or emotional change. Twenty-nine mild-to-moderate adverse events occurred overall, somewhat more often with Ze 91019 than placebo, but the difference was not statistically significant, and no serious adverse events occurred. These results support Ze 91019 as a generally well-tolerated option for occasional sleep difficulty that does not appear to blunt next-day thinking or mood, unlike many conventional hypnotics. However, this was explicitly a feasibility study with no formal power calculation, exploratory statistics, and only 40 completers at a single site, so the sleep-duration effect needs confirmation in a larger, adequately powered trial. Because valerian and hops were tested only as a fixed combination, the individual contribution of each herb remains unclear, and longer studies are needed to see whether cognitive benefits emerge over time.