Hops

Metadata

Approved Indications

Commission E (Germany)

• Approved: Mood disturbances such as restlessness and anxiety; sleep disturbances

ESCOP

• Approved: Tenseness, restlessness, difficulty in falling asleep

EMA/HMPC

• Traditional use (standalone): Relief of mild symptoms of mental stress and to aid sleep
• Traditional use (combination with valerian): Relief of sleep disorders — a separate EMA monograph exists for the valerian root + hop strobile combination

Agreement/Disagreement

All monograph bodies agree on the dual indication of restlessness/anxiety and sleep, though all classify hops under traditional use only (not well-established use). The EMA’s issuance of a separate combination monograph with valerian reflects the clinical reality that hops is most commonly used and studied in this combination.

Conditions Treated

Primary (Traditional Use)

• Sleep disturbances — Difficulty falling asleep, poor sleep quality
• Mild nervous restlessness — Tension, anxiety, irritability

Secondary (Limited/Emerging Evidence)

• Menopausal symptoms — 8-prenylnaringenin is a potent phytoestrogen [NEEDS-RESEARCH for clinical significance]
• Shift-work sleep disruption — One study in female nurses with non-alcoholic beer

Almost Always Used in Combination

• Hops + Valerian — The dominant clinical combination; has its own EMA monograph
• Hops + Valerian + Passionflower — Triple combination in some products
• Hops + Valerian + Lemon Balm — Another common combination

Mechanism of Action

Primary Mechanism: GABAergic Modulation

1. 2-methyl-3-buten-2-ol (methylbutenol): This degradation product of alpha-bitter acids (humulones) is considered the principal sedative constituent. It enhances GABA-A receptor activity. Notably, this compound is not present in fresh hops but forms during drying and storage as alpha acids degrade. This explains the traditional observation that aged hops are more sedative than fresh hops.

2. Bitter acid fractions: Both alpha acids (humulones) and beta acids (lupulones) have central GABAergic effects. The sedating effects appear to result from three categories of constituents acting synergistically: alpha acids, beta acids, and essential oils.

Secondary Mechanisms

3. Melatonin receptor activity: Hops extract has been reported to bind to melatonin (MT1) receptors, potentially contributing to circadian rhythm regulation and sleep onset [UNCERTAIN — in vitro data, limited clinical correlation]

4. Serotonin receptor modulation: Some evidence for 5-HT activity

5. Phytoestrogenic activity: 8-prenylnaringenin is one of the most potent known phytoestrogens, with affinity for estrogen receptors. This is relevant to menopausal symptom relief but not directly to the sedative/sleep indication.

Key Pharmacological Note

The active sedative constituent (2-methyl-3-buten-2-ol) is a degradation product, meaning:

• Fresh hops have less sedative activity than dried/aged hops
• Extract preparation method matters significantly
• The volatile nature of this compound means standardization is challenging

Clinical Evidence Summary

Standalone Hops Evidence (Very Limited)

Franco et al. (2012) — Non-Alcoholic Beer Study

• Design: Prospective, randomized
• n = 17 female nurses working rotating shifts
• Intervention: 333 mL non-alcoholic beer (containing hops) with dinner for 14 days
• Result: Improved sleep quality (Pittsburgh Sleep Quality Index), reduced sleep latency, decreased anxiety
• Limitation: Very small sample; non-alcoholic beer contains other compounds; no isolated hops control
• [Source: PMC3399866]

Franco et al. (2012) — Hops on Activity/Rest Rhythm

• Supplementation with hops at doses close to those in non-alcoholic beer (1-11 mg hop extract)
• Showed sedative effects on activity/rest rhythm
• [Source: PubMed 22849837]

General Assessment

There are essentially no large, rigorous, placebo-controlled RCTs of hops as a standalone sedative. The evidence base consists of very small studies, often using non-alcoholic beer as the delivery vehicle.

Valerian-Hops Combination Evidence (Somewhat Better)

Morin et al. (2005) — Valerian-Hops vs. Diphenhydramine

• Design: RCT, placebo-controlled
• n = 184 patients with mild insomnia
• Valerian 187 mg + Hops 42 mg vs. Diphenhydramine 25 mg vs. Placebo, 28 days
• Result: Modest improvement in sleep latency and quality for both active treatments, but not statistically significant difference from placebo for the primary endpoint

Koetter et al. (2007) — Fixed Valerian-Hops Combination

• Design: DBRPCT
• n = 30 patients with non-organic insomnia
• Valerian 500 mg + Hops 120 mg vs. Placebo
• Result: Significant reduction in sleep latency. Time in deeper sleep stages increased.

EMA/HMPC Assessment

• The combination monograph acknowledges traditional use for relief of sleep disorders
• Notes that combined use may be associated with improvements in sleep latency and sleep quality
• Evidence is classified as traditional use, not well-established use

Systematic Review (2010)

• Review of valerian-hops combination for treating primary insomnia
• Found modest evidence for improved sleep parameters (sleep latency, quality of sleep)
• Concluded that evidence was suggestive but not definitive
• [Source: RACGP/NCBI NBK79967]

European vs. US/Anglophone Consensus

Safety Profile

Contraindications

• Known hypersensitivity to hops or other Cannabaceae
• Estrogen-sensitive conditions: Due to 8-prenylnaringenin’s potent phytoestrogenic activity, some caution may be warranted in estrogen receptor-positive breast cancer, endometriosis, or uterine fibroids [UNCERTAIN — clinical significance at standard sedative doses unclear]
• EMA: Not recommended for children under 12 years (lack of data)

Drug Interactions

• Additive sedation: Theoretical with CNS depressants, benzodiazepines, barbiturates, alcohol
• Estrogen-related: Theoretical interaction with hormone therapy or tamoxifen due to phytoestrogenic activity [UNCERTAIN]
• CYP450: Some in vitro evidence for CYP1A2 and CYP2C inhibition, but clinical significance not established
• Overall: No significant drug interactions documented in clinical use

Side Effects

• Very safe at recommended doses
• Contact dermatitis: Occupational exposure in hop harvesters can cause allergic skin reactions (not relevant to oral medicinal use)
• GI complaints: Rare, mild
• Anaphylaxis: Extremely rare case reports from occupational exposure

Pregnancy and Lactation

• Pregnancy: Not recommended. Phytoestrogenic activity is a theoretical concern. Insufficient safety data.
• Lactation: Not recommended. Insufficient data. Traditional use as a galactagogue exists but is not supported by evidence.

Special Note on Phytoestrogens

8-prenylnaringenin in hops is one of the most potent known phytoestrogens. While the amounts in sedative preparations are likely well below levels that would cause systemic estrogenic effects, this is an area of ongoing research, particularly regarding menopausal symptoms.

Clinical Dosage

Standalone (Traditional)

• Dried strobiles: 0.5-1 g as tea, 2-3 times daily, or 1-2 g at bedtime
• Liquid extract (1:1, 45% ethanol): 0.5-2 mL, 1-3 times daily
• Tincture (1:5, 60% ethanol): 1-2 mL, 1-3 times daily

In Combination with Valerian (Most Common Clinical Use)

• Typical combination: Valerian 187-500 mg + Hops 42-120 mg, taken at bedtime
• EMA combination monograph: Various preparation ratios accepted under traditional use

Duration

• If symptoms persist after 2 weeks, consult a physician
• No maximum duration specified

Sources

• EMA/HMPC Final Assessment Report on Humulus lupulus L., flos (Revision 1)
• EMA/HMPC Assessment Report on Valeriana officinalis L., radix and Humulus lupulus L., flos (combination)
• EMA/HMPC European Union Herbal Monograph: Valerianae radix and Lupuli flos (combination)
• Commission E Monograph: Hops
• ESCOP Monograph: Lupuli flos
• Restorative Medicine Monograph: Hops (Humulus lupulus)
• Franco L et al. The Sedative Effect of Non-Alcoholic Beer in Healthy Female Nurses. PLoS One. 2012. PMC3399866
• Franco L et al. The sedative effects of hops. PubMed 22849837
• Morin CM et al. Valerian-hops combination and diphenhydramine for treating insomnia. Sleep. 2005
• Treating primary insomnia — the efficacy of valerian and hops. RACGP. NCBI NBK79967
• Zanoli P et al. New insight in the neuropharmacological activity of Humulus lupulus L. J Ethnopharmacol. 2005

Connections

• Combination with valerian: see Valerian (the primary clinical context for hops)
• GABA mechanism shared with: Valerian, Kava, Passionflower
• Compare standalone evidence with stronger sleep herbs: Valerian