hops benefits and side effects
Hops (Humulus lupulus L.)
Hops, belonged to the family of Cannabacea, are believed to benefit conditions such as anxiety and
insomnia. A few animal studies have demonstrated its effects on sleep quality or anxiety, but more advanced
studies are definitely needed to prove its possible uses for such conditions. On the other hand, some
marketers have suggested hops combined with valerian for maximum sedative or relaxing effects. Hops
contain phytoestrogen; intake of hopes may alter our hormonal conditions.

The female flowers of the hop plant have long been used as a preservative and a flavoring agent in beer, but
they are now being included in some herbal preparations for women for "breast enhancement." [4] Most
commercial hops extracts are standardized to 5.2% bitter acids and/or to 4% flavonoids per dose.


Hops have potential use or benefits on anxiety and insomnia.
The justification to use hops on anxiety and insomnia are mainly based on experiences from our ancestors.
There are extremely limited amounts of scientific evidence to support the claim of its benefits on sleep
quality, anxiety, insomnia or related conditions:

Dr. K-H Schiller from Hoexter demonstrated that hop preparations reduced the spontaneous locomotor
activity, increased the ketamine-induced sleeping time and reduced body temperature, confirming a central
sedating effect. However, he couldn't found any indication of anxiolytic activities of the preparation. Anyway,
he believed that hop oil and beta-bitter acid play a central role on sedating activities of his preparations. [15]

Zanoli P, et al, from  University of Modena and Reggio Emilia, Italy noticed hop extracts and its fraction both
could prolong pentobarbital sleeping time, without affecting the latency to the loss of the righting reflex in a
study of rats. The effect was dose-dependent, starting from a minimal dose of 10 mg/kg. Neither the extract
nor its alpha-acid fraction affected the locomotor activity in the open field test or exerted an anxiolytic effect
in rats submitted to the elevated plus-maze test. They also observed an antidepressant activity of the
extracts or faction prepared. [16]

Hops may have anti-inflammation effects and benefit arthritis.
Researchers from Germany showed the inhibitory effects of various ethanolic hop extracts containing
glucosides on COX-1 activity. The inhibitory potential of the glucosides decreased with increasing length of
the acyl side chain. [13]

Hops compounds may have potential chemopreventive activity against breast and ovarian
Researchers from Oregon State University isolated a few flavonoids from hops and tested for their
antiproliferative activity in human breast cancer (MCF-7), colon cancer (HT-29) and ovarian cancer (A-2780)
cells in vitro. They found chalcone and flavanone isomer of xanthohumol may have benefits of cutting cancer
risks in the study. [3,5] While, researchers from University of Illinois at Chicago analyzed the anti-cancer
activities of hops by studying its antioxidative activities and its effect on the detoxification of a potentially toxic
quinone (menadione). They found hop extract has a strong induction of quinone reductose in Hepa 1c1c7
cells. Quinone reductase is a detoxifying enzyme, protecting against quinone-induced toxicity. [7]

Finally, Japanese researchers suggested the anti-cancer activities of hop extracts are related to the
inhibition of the production of nitric oxide. It is known that nitric oxide (NO) plays an important role in many
inflammatory responses and is also involved in carcinogenesis. They then demonstrated the inhibitory effect
of extracts from Humulus lupulus L. on both the production of NO and the expression of inducible NO
synthase (iNOS) in mouse macrophage RAW 264.7 cells. Thus, the chalcones, including xanthohumol,
significantly inhibited the production of NO by suppressing the expression of iNOS. [8]

Hops have phyto-estrogen.
Researchers from King's College, UK, identified a potent phytoestrogen in hops, 8-prenylnaringenin, which
has an activity greater than other established plant estrogens. 8-Prenylnaringenin competed strongly with
17ss-estradiol for binding to both the alpha- and ss-estrogen receptors. [4] Its strong estrogenic activity was
also reflected in its relative binding affinity to estrogen receptors from rat uteri.  This phytoestrogen can also
be detected in beer containing hops, but the levels are low. [2]

Hops may have benefits of anti-microbial and anti-HIV-1 activities.
Researchers from Netherlands have shown the activities of hop extracts and oils against Gram-positive
bacteria (Bacillus subtilis and Staphylococcus aureus) and fungus (Trichophyton mentagrophytes var.
interdigitale) by chromatographic methods. [1]

It has been believed that xanthohumol contritbutes to most of the anti-microbial benefits of hop extracts or
related products. Xanthohumol was shown to inhibit the Gram-positive bacteria Staphylococcus aureus and
Streptococcus mutans. Antiviral activity was demonstrated against bovine viral diarrhea virus,
cytomegalovirus, herpes simplex virus type 1 and 2 and human immunodeficiency virus 1. Inhibition of two
Trichophyton spp. was indicative of antifungal activity. Finally, Xanthohumol potently inhibited the replication
of Plasmodium falciparum, the causative agent of malaria. This effect was linked to the inhibition of
glutathione-mediated degradation and detoxification of haemin, a by-product of the parasitic digestion of
haemoglobin. [14] Researchers from Chinese Academy of Sciences noticed that xanthohumol was effective
against HIV-1 in a study of C8166 lymphocytes. Xanthohumol inhibited HIV-1 induced cytopathic effects, the
production of viral p24 antigen and reverse transcriptase in C8166 lymphocytes at non-cytotoxic
concentration. Xanthohumol also inhibited HIV-1 replication in PBMC with EC50 value of 20.74 microg/ml. [9]

Side Effects, Drug Interactions and Warnings of Hops
Handling of hops may cause allergies (skin rash), dry cough and breathing difficulties [6]. Hops may cause
mild central nervous system depression with symptoms of drowsiness, slowed breathing and thinking. In
serious cases or overdoses, its side effects may include seizure, hyperthermia, restlessness, vomiting, and
stomach disturbance [9]. It is unclear how intake of hops alters the hormone-sensitive conditions such as
certain types of cancers.

Because of its sedative action, user should not use hops together with other CNS depressors including
benzodiazepines, narcotics, barbiturates, and some herbal sedatives. As it contains phyto-estrogen, users
should avoid hops products if they are on hormone replacement therapy or related medications. [11,12]
Some animal studies shows that hops may lower blood sugar levels. Hops may amplify the effects of diabetic
medications or other supplements (such as ginseng, bilberry, gymnema, fish oil etc.) leading to
hypoglycemia. Check with your doctor before taking any supplements.

[1] Langezaal CR, Chandra A, Scheffer JJ. Antimicrobial screening of essential oils and extracts of some Humulus lupulus
L. cultivars.Pharm Weekbl Sci. 1992 Dec 11;14(6):353-6. [2] Milligan SR, et al, Identification of a potent phytoestrogen in
hops (Humulus lupulus L.) and beer. J Clin Endocrinol Metab. 1999 Jun;84(6):2249-52. [3] Miranda CL, et al,
Antiproliferative and cytotoxic effects of prenylated flavonoids from hops (Humulus lupulus) in human cancer cell lines.
Food Chem Toxicol. 1999 Apr;37(4):271-85. [4] Milligan SR et al, The endocrine activities of 8-prenylnaringenin and
related hop (Humulus lupulus L.) flavonoids.J Clin Endocrinol Metab. 2000 Dec;85(12):4912-5. [5] Yilmazer M, et al, In
vitro biotransformation of xanthohumol, a flavonoid from hops (Humulus lupulus), by rat liver microsomes.Drug Metab
Dispos. 2001 Mar;29(3):223-31. [6] Spiewak R, Dutkiewicz J.Occupational airborne and hand dermatitis to hop (Humulus
lupulus) with non-occupational relapses.Ann Agric Environ Med. 2002;9(2):249-52. [7] Dietz BM, et al, Xanthohumol
isolated from Humulus lupulus Inhibits menadione-induced DNA damage through induction of quinone reductase. Chem
Res Toxicol. 2005 Aug;18(8):1296-305. [8] Zhao F, et al, Inhibitors of nitric oxide production from hops (Humulus lupulus
L.). Biol Pharm Bull. 2003 Jan;26(1):61-5. [9] Wang Q, et al, Xanthohumol, a novel anti-HIV-1 agent purified from Hops
Humulus lupulus. Antiviral Res. 2004 Dec;64(3):189-94. [10] Kurasawa T, et al, Effect of humulus lupulus on gastric
secretion in a rat pylorus-ligated model. Biol Pharm Bull. 2005 Feb;28(2):353-7. [11] Overk CR, et al, Comparison of the
in vitro estrogenic activities of compounds from hops (Humulus lupulus) and red clover (Trifolium pratense). J Agric Food
Chem. 2005 Aug 10;53(16):6246-53. [12] Chadwick LR, et al, The pharmacognosy of Humulus lupulus L. (hops) with an
emphasis on estrogenic properties. Phytomedicine. 2006 Jan;13(1-2):119-31. Epub 2005 Jul 1. [13] Bohr G, et al,
Anti-inflammatory acylphloroglucinol derivatives from Hops (Humulus lupulus). J Nat Prod. 2005 Oct;68(10):1545-8. [14]
Gerhauser C. Broad spectrum anti-infective potential of xanthohumol from hop (Humulus lupulus L.) in comparison with
activities of other hop constituents and xanthohumol metabolites. Mol Nutr Food Res. 2005 Sep;49(9):827-31. [15]
Schiller H, et al, Sedating effects of Humulus lupulus L. extracts. Phytomedicine. 2006 Jul 21. [16] Zanoli P, et al, New
insight in the neuropharmacological activity of Humulus lupulus L. J Ethnopharmacol. 2005 Oct 31;102(1):102-6.
Discuss with your doctor before taking any alternative medicine. This article is for reference only, it
is not a medical advice. All rights reserved.  Portions of this article may be freely copied to other
blogs and websites, but credit and link to this article are required. August 27 2011