Hops (Humulus lupulus) have a history of use in the treatment of several different symptoms of agitation, including restlessness, anxiety, insomnia, nervous tension, and irritability. Its modern use has been employed in attention-deficit hyperactivity disorder, or ADHD. Legend states that hops calming ability came to light after workers assigned to harvest them were overcome with drowsiness as they continued to work in the fields.  Hops were used as a brewery ingredient in the Netherlands starting in the 14th century and in England two centuries later.
Historically, there were also many other variable uses of this herb, including; treatments for indigestion, tuberculosis, colitis, bladder infection, neuralgia , and leg ulcers. Today, hops are still used for brewing beer, and hop extracts and oils are used for flavor enhancers in other foods. Hops may be found in lotions and skin moisturizers as well.
The medicinal component of the hop plant is the female flower, or strobile. Among the main active constituents of the plant are the flavonoids, of which 9 have been identified in hops.  Research has not clearly identified the component of the plant responsible for its purported sleep-inducing qualities.
The other ingredient of interest found in hops is the phytoestrogen constituent known as 8-prenylnarignenin; this flavonoid has a similar chemical structure to estradiol (a type of estrogen), as well as to a type of prescription drug known as a selective estrogen-receptor modulator (SERM).  Extracts of hops can prevent the binding of estradiol to its receptors in the body and can activate cells in much the same way regular estradiol does.  The estrogenic activity of hops is thought to be caused by the phytoestrogen component of the plant. 
Hops is used today mainly as a very mild sedative (studies investigating this effect are minimal and those that do show a sedative effect used a combination of hops and valerian, another sedative herb). 
Other applications include its use as a digestive stimulant (especially for starch digestion), and as an antimicrobial compound.
As an herb with phytoestrogens, it may be found in some women’s health products to assist with regulation of menses and menopausal symptoms.
Typical dosing of hops, in their dried form, is roughly one half gram, taken one to three times per day. In a tincture form, 150 drops of the extract can be taken 15 minutes before bedtime or upon the anticipation of nervousness. 
Hops are generally well tolerated and reports of side effects are minimal. The safety concerning its administration during pregnancy and lactation is not available at this time.  However, when used topically, hops can cause allergic contact dermatitis. This is most likely due to its pollen content.
Hops General interactions (supplement, herb, food, lab):
Use of hops with any food, herb, or nutritional supplement that has sedative effects may lead to enhanced effects. Some of these sources include; 5-HTP, Kava, California poppy, Valerian, and Skullcap.
Hops Drug interactions:
Taking hops with alcoholic beverages may potentiate the effects of alchohol on the brain. Using hops with other drugs that have depressive effects on the brain may lead to enhanced effectiveness as well. 
Theoretically, using hops in those with a propensity toward depression may further accelerate this condition. 
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