The plant Humulus lupulus, commonly known as hops, is widely recognized for its role in beer production, but its use as an herbal remedy predates its culinary application by centuries. Historically, the female cones of the hops plant have been employed in traditional medicine systems to address a variety of ailments. Modern investigation has begun to isolate and understand the specific compounds within the plant responsible for its observed effects. This research establishes a scientific foundation for the traditional uses of this flowering vine and explores its application in supporting human health.
Key Active Compounds and Their Functions
The majority of hops’ therapeutic properties are concentrated within the resinous lupulin glands found on the female flower cones. These glands contain a complex mixture of compounds, including alpha acids, beta acids, and prenylated chalcones. Alpha acids (primarily humulones) and beta acids (such as lupulones) are bitter acids that contribute flavor to beer and display antibacterial properties.
These bitter acids, along with their degradation products, also contribute to the plant’s calming effects. The prenylated chalcones include Xanthohumol and 8-prenylnaringenin (8-PN). Xanthohumol is noted for its antioxidant activity and is the most abundant prenylated flavonoid in hops.
Supporting Healthy Sleep and Relaxation
Hops have been traditionally used as a mild sedative, a practice often attributed to the historical observation that hop pickers would become drowsy while harvesting the flowers. This sedative effect is now understood to be linked to the interaction of certain hop compounds with the central nervous system. Specifically, the alpha acid humulone, a component of the hop resin, has been shown to act as a positive modulator of \(\text{GABA}_{\text{A}}\) receptors.
The \(\text{GABA}_{\text{A}}\) receptor is the primary inhibitory neurotransmitter system in the brain, and its activation leads to a reduction in neuronal excitability, promoting relaxation and sleep. By positively modulating this receptor, hop compounds essentially enhance the natural calming signals within the brain. This mechanism helps to reduce the time it takes to fall asleep, a metric known as sleep latency, and can improve overall sleep quality.
This calming action is often leveraged in combination with other botanicals, most notably valerian root, in commercial sleep preparations. When used together, hops and valerian appear to offer a synergistic effect, compounding the mild sedative properties of each plant. The combination is frequently recommended for addressing anxiety, restlessness, and mild insomnia.
Impact on Hormonal Balance and Menopause Symptoms
Hops are a significant source of phytoestrogens, which are plant-derived compounds that mimic the action of the hormone estrogen in the body. Among these compounds, 8-prenylnaringenin (8-PN) is considered the most potent phytoestrogen discovered to date. This compound exhibits a high affinity for estrogen receptors, particularly the \(\text{ER-}\alpha\) subtype, allowing it to exert estrogen-like effects.
This estrogenic activity makes hops extracts an option for managing symptoms associated with the decline in estrogen levels during menopause. Clinical studies have indicated that extracts standardized for 8-PN content can significantly reduce the frequency and severity of vasomotor symptoms. This includes alleviating hot flashes and night sweats, which are among the most common and disruptive complaints of menopausal women.
The use of 8-PN is being researched as a potential alternative to traditional hormone replacement therapy. By interacting with estrogen receptors, the compound may also support other areas affected by hormonal changes, such as bone health.
Anti-inflammatory and Antioxidant Protection
Beyond its sedative and hormonal effects, hops contain compounds that offer protective benefits for cellular health, particularly through antioxidant and anti-inflammatory actions. Xanthohumol (\(\text{XN}\)), a prenylated chalcone, is a powerful antioxidant that directly neutralizes reactive oxygen species, protecting cells from oxidative stress damage.
The anti-inflammatory effects of hops are largely mediated by \(\text{XN}\)‘s ability to modulate complex signaling pathways within the body. Xanthohumol has been shown to interfere with the \(\text{NF-}\kappa\text{B}\) pathway, a central regulator of the inflammatory response. By inhibiting \(\text{NF-}\kappa\text{B}\) nuclear translocation, \(\text{XN}\) reduces the production of pro-inflammatory mediators such as \(\text{TNF-}\alpha\) and \(\text{IL-}6\).
Additionally, \(\text{XN}\) activates the \(\text{Nrf2}\) pathway, which is the body’s master regulator of endogenous antioxidant defenses. This activation leads to the increased production of protective enzymes like \(\text{heme}\) \(\text{oxygenase-1}\) (\(\text{HO-1}\)), further enhancing the body’s ability to combat free radicals and oxidative damage. The dual action of directly neutralizing free radicals and boosting the body’s internal defenses supports metabolic and cardiovascular health.
Considerations for Safe Consumption
Hops are widely consumed in various forms, including herbal teas, liquid tinctures, and standardized dietary supplements. For medicinal use, standardized extracts are common, with doses up to 300 mg daily of a hop extract or 35 mg daily of hop bitter acids generally considered safe for short-term consumption. The sedative nature of hops means that dizziness and increased sleepiness are possible side effects, particularly at higher doses.
Because hops exert a depressant effect on the central nervous system, they should be used with caution when combined with other sedating substances, including alcohol, prescription sedatives, or anesthesia. Individuals are advised to stop using hop supplements at least two weeks before any scheduled surgical procedure.
Due to the presence of potent phytoestrogens, hops are contraindicated for people with hormone-sensitive conditions, such as certain types of breast cancer or endometriosis. Avoidance is recommended during pregnancy and breastfeeding due to insufficient reliable safety information.