The female inflorescence of hops (Humulus lupulus, Cannabaceae) is used traditionally to treat insomnia, excitability, and restlessness. The German Commission E approved the use of hops for sleep disturbances and mood disorders such as anxiety and restlessness; however, according to the authors, there is a lack of high-quality, placebo-controlled studies evaluating the efficacy of hops in reducing stress-related symptoms. Hence, the purpose of this randomized, placebo-controlled, double-blind, crossover study was to assess the effects of the commercially available hops dry extract on depression, anxiety, and stress levels in healthy young adults.
Healthy students (n = 42, aged > 18 years) attending Harokopio University in Athens, Greece, with at least mild self-reported symptoms of depression, anxiety, and stress according to the Depression Anxiety Stress Scale-21 (DASS-21) participated in the trial (study dates not reported). Exclusion criteria were any systemic disease (e.g., neurological or psychiatric disorders, including clinically diagnosed anxiety disorders and depression) or systemic treatment (e.g., sedatives, antidepressants, or supplements), changes in body weight > 3% of total body weight within the past 2 months, changes in physical activity levels within the past 2 months, and drug and/or alcohol use disorders.
Subjects were treated with either 400 mg/day hops dry extract (Melcalin® HOPs; Biotekna Srl; Marcon, Venice, Italy) or placebo (not described; Biotekna Srl) for 4 weeks and then were crossed over to the alternate treatment after a 2-week washout period. Subjects were asked to abstain from consuming products containing hops (i.e., beer), taking other supplements/vitamins (i.e., valerian [Valeriana officinalis, Caprifoliaceae] root or St. John’s wort [Hypericum perforatum, Hypericaceae] aerial parts), and significantly changing dietary and activity habits. At the beginning and end of each study period, anthropometric measurements were taken; symptoms of depression, anxiety, and stress were assessed with the DASS-21; and blood was collected to measure morning cortisol plasma levels. Adverse events (AEs) were collected via diary throughout the study.
Of the 42 subjects enrolled in the study, 6 (14.2%) did not complete the first treatment per protocol and were excluded from the analysis (3 in the hops group and 2 in the placebo group discontinued treatment, and 1 in the placebo group was lost to follow-up). Neither group had significant changes in body weight, body mass index, body composition parameters, or plasma cortisol levels (P > 0.05 for all).
Compared to placebo, the hops treatment significantly decreased DASS-21 subscores for anxiety (P = 0.009), depression (P = 0.001), and stress (P = 0.009). There were no significant correlations between any of the DASS-21 subscale scores and the other study variables (anthropometric measurements and plasma cortisol levels). There were no AEs reported for either group.
According to the authors, the extant literature on the clinical effects of hops pertains to trials evaluating combination products containing hops and this is the first placebo-controlled, randomized study to provide evidence that hops monotherapy significantly improves measures of self-reported depression, anxiety, and stress in otherwise healthy young adults. Cautions have been published regarding the use of hops in people with depression because the known sedative effects may heighten depressive symptoms and potentiate the soporific effects of antidepressant drugs; however, the results of the present study “suggest that hops may have an overall beneficial mood-enhancing effect without significant adverse/side effects in treatment-naïve individuals presenting with symptoms of both depression and anxiety/stress.”
Acknowledged limitations of this study include potential recruitment/selection bias, the use of subjective measures (although the DASS-21 is a well-validated instrument), the results cannot be generalized to other populations, only morning cortisol levels were measured (there may be diurnal variations), and other stress biomarkers were not assessed. The authors conclude, “Longer studies are required to explore the long-term efficacy and safety of this intervention, which should be also studied in older patients with depression and/or anxiety/stress disorders.”
This publication conformed with the Consolidated Standards of Reporting Trials (CONSORT) guidelines, except for the reporting of funding sources. The Melcalin HOPs and placebo treatments were provided by Biotekna Srl. The authors report no conflict of interest.
Kyrou I, Christou A, Panagiotakos D, et al. Effects of hops (Humulus lupulus L.) dry extract supplement on self-reported depression, anxiety and stress levels in apparently healthy young adults: a randomized, placebo-controlled, double-blind, crossover pilot study. Hormones (Athens). 2017;16(2):171-180.