Best known for their role in beer brewing, the female flowers of the hop are being increasingly used in supplements for insomnia, anxiety, and menopausal symptoms. In addition, research on their components has revealed new activities with promising clinical applications. Read below to learn more about hops’ health benefits.
Hops are the female flowers of hop (Humulus lupulus L.), a climbing plant belonging to the same family as hemp (Cannabaceae). Hop most likely originated in China, Southern Caucasus and Siberia, or Mesopotamia, from where it spread to Japan, America, and Central Europe [1, 2].
Due to its role in beer brewing, which accounts for 98% of its use, hop is nowadays cultivated in all warmer regions. The different compounds in hops add a bitter flavor to beer, prevent the growth of unwanted microorganisms during the brewing process, and stabilize foam .
Due to the scarcity of clinical studies, hops and its active components have not been approved by the FDA for medical use. Further research will be required to determine whether they are effective or safe for long-term use.
Nevertheless, hops extract is commercially available as a supplement. Regulations set manufacturing standards for supplements but don’t guarantee that they are safe or effective. Talk to your doctor before using hops supplements to avoid unexpected interactions.
Menopause is the cessation of menstrual cycles in women. It is accompanied by a reduction in female sex hormone levels, which causes symptoms such as :
- Hot flashes
- Night sweats
- Sleep disturbances
- Mood changes (depression, irritability)
- Bone and muscle mass loss
- Reduced sex drive
- Vaginal dryness
In a pilot trial of 100 women, a gel containing hops extract reduced vaginal dryness .
In several studies in female rats whose ovaries were removed to mimic menopausal hormone deficiency, hops extract or 8-prenylnaringenin reduced hot flashes, improved some bone mass and architecture parameters (although it worsened others), and increased sex drive [8, 9, 10, 11].
In a small trial on 72 menopausal women, a morning/evening formula in which the morning capsule contained ginseng, black cohosh, soy, and green tea extracts and the evening capsule contained black cohosh, soy, kava, hops, and valerian extracts improved several menopausal symptoms including hot flashes and sleep disturbances .
In a trial on 36 people with at least mild depression, stress, or anxiety, hops extract improved all the symptoms .
In rats, hops extract had antidepressant activity –measured as a reduction of the time that rats spent floating immobile in a cylinder filled with water .
In a small trial on 17 people, one can (333 mL, a bit more than 1 cup) of non-alcoholic beer improved sleep quality. Hop was suggested as the main beer component responsible for this effect .
Hops extract increased sleeping time and reduced physical activity and body temperature in mice and rats taking sedatives. In a study in quails, whose sleep-wake rhythm is very similar to that of humans, a dose of 2 mg hops extract was most effective in reducing night activity while preserving a normal circadian activity/rest rhythm [16, 14, 17, 18].
Hops are frequently combined with valerian to fight insomnia. In three trials on over 250 people, this combination was more effective than placebo. Two of them showed that the combination was also more effective than valerian alone [19, 20, 21].
Similarly, the combination of hops, valerian, and purple passionflower was as effective as the drug zolpidem in a trial on 78 people with insomnia .
In a trial on 200 healthy overweight people, hops extract reduced body fat, especially in the belly .
The combination of hops isohumulones and acacia proanthocyanidins improved several symptoms of metabolic syndrome. Together with diet changes and physical exercise, it decreased blood levels of triglycerides and cholesterol (total, LDL, APOB) in a trial on 23 people. The combination also reduced insulin levels while increasing insulin sensitivity in another trial on 91 people [33, 34].
Hops polyphenols reduced the capacity of two bacterial species (Streptococcus mutans and Streptococcus sobrinus) to cause cavities .
In a clinical trial on 39 people with allergies to pollen, hop extract improved nose swelling, nose color, discharge amount, and discharge characteristics .
In a study in human nose cells, hops water extract reduced the production of a cytokine that activates allergic inflammatory responses (TSLP) .
In a small trial on 23 people, hops isohumulones improved blood flow, both in smokers and non-smokers .
In rats, hops extract relaxed blood vessels, which may reduce the risk of heart disease .
Because xanthohumol inhibits platelet activity, it may reduce the risk of blood clot formation (thrombosis) .
In a small trial on 20 diabetic people, hops isohumulones reduced blood sugar levels .
In multiple studies with mice and rats, hops extract, its components xanthohumol and isohumulones, or a mixture of hops isohumulones and acacia proanthocyanidins reduced blood sugar levels and insulin resistance [26, 27, 28, 52, 53, 30].
Once again, this health benefit is only supported by one clinical trial and a few animal studies. Further research in humans should confirm these preliminary results.
The simultaneous activation of PPAR-alpha and PPAR-gamma by isohumulones may lower blood sugar levels by reducing insulin resistance. Hops bitter acids also activate the bitter taste receptors and stimulate the production of GLP-1, a protein that triggers insulin production in response to sugar [52, 54].
Xanthohumol may lower blood sugar levels by:
- Binding to the farnesoid X receptor [55, 56]
- Blocking sugar uptake 
- Blocking an enzyme that produces sugar from complex carbohydrates (α-glycosidase) 
While some hops flavonoids (e.g., quercetin) also reduce sugar uptake, others (e.g., catechin) increase it. The hops flavonoids catechin, epicatechin, quercetin, and rutin may also lower blood sugar levels by stimulating the growth of the cells that produce insulin (β-cells) [57, 59+].
In a small trial on 42 people, hops extract mixed with an odor adsorbent agent commonly found in commercial deodorants reduced underarm odor without causing irritation. In the same study, hops extract reduced the growth of two bacterial species responsible for underarm odor (Corynebacterium xerosis and Staphylococcus epidermidis) .
A combination of hops isohumulones, rosemary extract, and oleanolic acid reduced the pain caused by arthritis and fibromyalgia in a small trial on 54 people. More studies on larger populations are needed to confirm this potential benefit. Additionally, because the study used a combination of extracts, the specific contribution of hops to the effects observed is not clear .
Hops and their compounds are being researched for other potential health benefits. Because the research is still in the animal and cell stage, we cannot draw conclusions.
In several mice studies, hops or its components xanthohumol and isohumulones had protective effects against the following liver disorders:
- Alcoholic fatty liver disease [62, 63]
- Non-alcoholic fatty liver disease [64, 65]
- Oxidative damage, inflammation, and cell death associated with aging 
- Tissue scarring in response to liver damage 
In a study in pigs, dietary hops (or a grape product also rich in polyphenols) increased weight gain per feed intake. The new diet did not change gut morphology or feed digestibility, but changed the gut microbial composition and reduced the production of pro-inflammatory proteins .
Studies in humans should confirm these preliminary results.
The intake of hops extract or its components xanthohumol and lupulone reduced skin inflammation (measured as ear swelling) in three studies on mice with mite-induced dermatitis, contact allergic dermatitis, and exposed to a tumor promoter agent [71, 72, 73].
In an antimicrobial study, xanthohumol and lupulones reduced the growth of five microbes that cause acne (Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, Kocuria rhizophila, and Staphylococcus pyogenes). Hops compounds also blocked two activities of these bacteria that also contribute to the development of acne (anti-collagenase and oxidative) .
Hops extract reduced brain damage and maintained brain function in rats recovering from a stroke or poisoned with aluminum nitrate. In the long-term, hops extract reduced the buildup of a protein believed to cause Alzheimer’s disease (β-amyloid) in the brain of old mice and preserved their cognitive functions [75, 76, 77].
Because xanthohumol (among other flavonoids) can block an enzyme involved in the onset of Alzheimer’s disease (BACE1), it was suggested as a preventive therapeutic candidate for this disease .
The results of these studies will need to be repeated in larger and more robust studies to confirm a role for hops or its active compounds in preventing neurodegenerative diseases.
Hops essential oil and extracts inhibited [81+]:
- Yersinia enterocolitica
- Salmonella enteritidis
- Salmonella typhimurium
- Proteus mirabilis
- E. coli
- Klebsiella oxytoca
- Mycobacterium fortuitum, a relative of the bacterium that causes tuberculosis .
- Bacteria that may cause diarrhea (Bacteroides fragilis, Clostridium perfringens, Clostridium difficile)
- Antibiotic-resistant strains (Staphylococcus aureus, Enterococcus faecium)
- Bacteria that may cause food poisoning (Staphylococcus aureus and Staphylococcus epidermidis)
- Influenza A virus
- Rhinovirus (the common cold)
- Herpes simplex virus type 1 and 2
Hop’s xanthohumol enhanced the activity of interferon alpha (IFN-α) against a cow virus. Because this virus is very similar to hepatitis C virus, xanthohumol might be used to develop new therapies against it .
Xanthohumol also reduced HIV replication, the production of a virus, and the damage caused to cells. For these reasons, its investigation as a new therapeutic agent for HIV was suggested .
In a study in which five hop components were tested against four human fungal pathogens (Trichophyton mentagrophytes, Trichophyton rubrum, Candida albicans, and Mucor rouxianus), xanthohumol, isoxanthohumol, and 6-isopentenylnaringenin were identified as the most powerful antifungal agents .
It’s important to note that these are very preliminary results that have not yet been studied in humans or even in animals. Further research should determine if hops are effective against infections caused by these organisms when ingested in normal doses.
In a study in thyroid-derived cells, xanthohumol improved iodide uptake, which is an essential step in the production of the thyroid hormone. In another study, xanthohumol increased TSH and activity of the enzyme that converts T4 to T3 (type 1 deiodinase) [93, 94].
Preliminary research in animals and cells has found anticancer activity in several of hops’ constituents.
However, many substances –including downright toxic chemicals like bleach– have anti-cancer effects in cells. This doesn’t mean that they have any medical value. On the contrary, most substances (natural or synthetic) that are researched in cancer cells fail to pass further animal studies or clinical trials due to a lack of safety or efficacy.
Do not under any circumstances attempt to replace conventional cancer therapies with hops extract, its components, or any other supplements. If you want to use them as supportive measures, talk to your doctor to avoid any unexpected interactions.
The hops component xanthohumol reduced growth, survival, or migration in cells of the following cancer types:
- Prostate [95, 96, 97, 98]
- Liver [99, 100, 101]
- Pancreatic 
- Stomach 
- Colon [104, 105]
- Breast [106, 107, 108]
- Ovarian [106, 105]
- Cervix [109, 110]
- Lung [111, 109, 105]
- Brain 
- Skin 
- Laryngeal 
- Thyroid 
- Leukemia [115, 116]
Other hops flavonoids such as isoxanthohumol, 6-prenylnaringenin, and 8-prenylnaringenin also showed activity against the following cancer types:
- Prostate [117, 98]
- Kidney 
- Breast [108, 106, 118]
- Colon 
- Ovarian 
- Burkitt lymphoma 
- Skin 
Although they have also been tested in animals and cells, only one clinical trial on a small population (17-42 people) supports each of the following health benefits of hops:
- Improvement of mood disorders 
- Sedative 
- Antiallergic 
- Antioxidant 
- Improvement of insulin resistance 
- Deodorant 
The following benefits have only been tested in animal and cell studies:
- Activity against infectious agents [81, 88, 91, 85]
- Anticancer [122, 2]
- Anti-inflammatory [72, 122]
- Protection against brain damage [79, 78, 75]
- Skin health promotion [71, 74]
- Protection against heart disease [47, 48, 50, 51]
- Protection against liver damage [63, 65, 66, 64]
- Improvement of digestive function [68, 70]
- Improvement of thyroid function [93, 94]
Therefore, more clinical trials involving larger amounts of people are required to confirm these claims.
Although doses of up to 239 mg hops extract per day during 7-day periods caused no toxicity symptoms, no long-term toxicity studies have been carried out .
- What are Hops? + Plant & Extract Components & Side Effects
Hops are the female flowers of hop (Humulus lupulus L.), a climbing plant belonging to the same family as hemp (Cannabaceae). 98% of the modern use of hops is in beer brewing, but research is ongoing into its potential health benefits.
Because of its phytoestrogens, the best evidence comes from research into menopausal symptoms. Other clinical research has found possible benefits for mood disorders, sleep, metabolic health, dental health, allergies, heart health, blood sugar, and pain, but these studies were small and of low quality. Finally, hops may have a use as a deodorant. Additional research in animals and cells may yet uncover additional potential benefits for hops.