Hops (Humulus lupulus) is best known as a beer ingredient, but the same plant compounds have a real pharmacology — the strobile (flower) extract has been studied for calming, sedative effects independent of alcohol. It's also one of the ingredients in Proco's Sleep Support blend. Here's what the actual trial evidence shows.
Long before anyone put hops through a randomized trial, European herbal tradition had already claimed it: dried hop cones stuffed into pillows, hop tea taken as a folk sleep aid, and — per brewing lore — hop-pickers said to nod off in the fields from handling the flowers all day. That history is likely why researchers thought to test hops for sleep and calming effects in the first place. But tradition isn't evidence. A hop pillow was never a controlled experiment. What follows is what's actually been measured.
The trial
A randomized, double-blind, placebo-controlled crossover trial gave healthy young adults a hops dry extract (two 0.2g capsules daily) for two 4-week periods, separated by a 2-week washout. Of 42 people enrolled, 36 completed the study (31 female, 5 male; mean age 24.7). Anxiety, depression and stress were measured using the DASS-21, a standard self-report scale.
What it found
All three measures improved significantly more on hops than on placebo: anxiety scores fell from 9.2 to 5.1, depression from 11.9 to 9.2, and stress from 19.1 to 11.6 (all p<0.05). Cortisol levels and body composition didn't change in either group — the effect showed up in how people felt, not in a measured stress hormone.
How hops might work
Hops contains two main classes of compounds researchers have looked at for central nervous system effects: bitter acids (alpha-acids like humulone, beta-acids like lupulone) and prenylated flavonoids, most notably 8-prenylnaringenin and its close relative 6-prenylnaringenin. 8-Prenylnaringenin is actually better known for a different reason — it's one of the most potent phytoestrogens ever identified in a plant — but several of these same compounds have also been screened for activity at GABA-A receptors, the same receptor system benzodiazepines, alcohol and z-drugs act on to produce calming and sedative effects.
A 2020 laboratory study testing hops compounds against rat GABA-A receptors found that humulone and 6-prenylnaringenin were the most potent modulators, positively enhancing GABA's inhibitory signaling at low micromolar concentrations — a mechanism consistent with a calming effect.3 Interestingly, the effect persisted even when the researchers added flumazenil, a drug that blocks the classic benzodiazepine binding site — suggesting hops compounds may work on GABA-A receptors through a different route than drugs like diazepam, not simply mimicking them. Separately, older animal research raised a second, more speculative mechanism: a 2007 study in mice found that the body-temperature-lowering (hypothermic) effect of a hops extract was blocked by luzindole, a melatonin-receptor antagonist — hinting that hops compounds may have some activity at the same receptors melatonin binds to.4
Is there other human trial evidence for hops?
Beyond the Aston University crossover trial, dedicated human research on hops by itself is sparse. The one other notable randomized trial involving hops paired it with valerian: a 2005 multicenter, placebo-controlled, parallel-group trial published in the journal Sleep gave 184 adults with mild insomnia (110 women, 74 men; mean age 44.3) either a valerian-hops combination tablet (187mg valerian extract plus 41.9mg hops extract, two tablets nightly), diphenhydramine (the antihistamine used in most over-the-counter sleep aids), or placebo for 28 days.2 The valerian-hops combination showed a greater reduction in sleep latency by day 28 and a significant improvement in a physical quality-of-life measure versus placebo; diphenhydramine performed better on sleep efficiency in the first two weeks. Neither treatment produced rebound insomnia or serious side effects when stopped.
A two-ingredient trial can tell you the combination worked. It can't tell you which ingredient did the work.
That's the honest limit of the 2005 trial for our purposes: it's a real, published, placebo-controlled result, but because valerian and hops were dosed together, it can't isolate what hops contributed versus what valerian contributed. It's the same logic we apply to Sleep Support's own 14-ingredient blend later in this article — a combination result isn't the same evidence as a single-ingredient result, even when the combination works.
How hops compares to Sleep Support's other sleep botanicals
Sleep Support isn't just hops — it also contains valerian and passion flower, two botanicals we've written about separately (linked below). Here's how the trial evidence for each actually compares, based on the specific studies discussed in this article and in those posts.
| Botanical | Evidence base | Population | Consistency |
|---|---|---|---|
| Hops | 1 standalone RCT (n=36 completers), plus 1 hops+valerian combo RCT (n=184) that can't isolate hops | Healthy young adults, mostly female | Not independently replicated |
| Valerian | 16 RCTs pooled in a 2006 meta-analysis (n=1,093 combined)5 | Mixed adult populations across trials | Modest overall signal; authors flagged inconsistent preparations/doses and possible publication bias |
| Passion flower | 1 pilot head-to-head RCT vs. a prescription anxiolytic (n=36)6 | Adults with diagnosed generalized anxiety disorder | Single small trial; not yet independently replicated at this scale |
Valerian has the largest cumulative evidence base of the three by trial count and total participants, but the authors of its own meta-analysis were candid that the underlying studies used inconsistent preparations and doses and that the pooled result showed signs of publication bias — more data hasn't necessarily meant cleaner data. Passion flower's strongest single trial is smaller than hops' but notable for a different reason: it tested a plant extract directly against oxazepam, a real prescription benzodiazepine, in people with a clinically diagnosed anxiety disorder rather than healthy volunteers — both arms saw roughly a 68% reduction in anxiety scores over 28 days, with oxazepam working faster and passion flower showing less impairment of job performance.6 Hops, by contrast, has exactly one dedicated human trial, in healthy (not clinically anxious) young adults, that hasn't yet been repeated by an independent research group. Of the three botanicals discussed across Proco's blog, hops is honestly the thinnest-evidenced — not because the one trial it has is bad, but because it's the only one it has.
The honest limits
This is one trial, in a small (n=36), young, mostly-female, healthy population — not older adults, not a clinical anxiety or depression sample, and not yet independently replicated by a different research group. The outcomes were self-reported, not clinician-assessed. That's a real, statistically significant signal, not proof at the level we'd want before making a standalone product claim — which is exactly why hops sits inside a multi-ingredient sleep blend rather than as its own dosed product.
Why it's in Sleep Support
Hops is one of the 14 ingredients in Sleep Support's proprietary blend, alongside valerian, passion flower, chamomile and others with their own evidence bases. Like the rest of that blend, hops isn't yet individually dosed on the label — that's something we're actively closing. The trial evidence above is for hops on its own, at a specific dose; it doesn't tell us exactly what hops contributes at whatever amount is in Sleep Support's blend. We're publishing what the ingredient-level evidence actually shows so you can judge it for yourself, not implying the blend has been tested this way.
This article is for informational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent anxiety, depression, or any other condition.
References
- Randomized, double-blind, placebo-controlled crossover trial of hops (Humulus lupulus L.) dry extract on self-reported depression, anxiety and stress in healthy young adults. research.aston.ac.uk/en/publications/effects-of-a-hops-ihumulus-lupulus-li-dry-extract-supplement-on-s
- Morin CM, Koetter U, Bastien C, Ware JC, Wooten V. Valerian-hops combination and diphenhydramine for treating insomnia: a randomized placebo-controlled clinical trial. Sleep. 2005. pubmed.ncbi.nlm.nih.gov/16335333
- Hops compounds modulatory effects and 6-prenylnaringenin dual mode of action on GABA-A receptors. 2020. pubmed.ncbi.nlm.nih.gov/32001220
- Hypothermic effects of hops are antagonized with the competitive melatonin receptor antagonist luzindole in mice. 2007. pubmed.ncbi.nlm.nih.gov/17430638
- Bent S, Padula A, Moore D, Patterson M, Mehling W. Valerian for sleep: a systematic review and meta-analysis. American Journal of Medicine. 2006. pubmed.ncbi.nlm.nih.gov/17145239
- Akhondzadeh S, Naghavi HR, Vazirian M, et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. Journal of Clinical Pharmacy and Therapeutics. 2001. pubmed.ncbi.nlm.nih.gov/11679026
Related reading
- Inside Sleep Support: An Honest Breakdown
- Passion Flower for Anxiety and Sleep: What the Trials Show
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