Hops (Humulus lupulus), typically used in the manufacturing of beer, has a long and proven history of herbal use, as a treatment for anxiety, restlessness, and insomnia. Hops is also employed for its soothing, sedative, tonic and calming effect on the body and the mind. Various humulus lupulus extracts can also found in regenerative and recovery bodybuilding supplements.
Hops (Humulus Lupulus) in Bodybuilding Supplements
About one-third of the adult population has some degree of insomnia symptoms at least occasionally and about 15% are dissatisfied with their sleep . For every bodybuilder sleep is a crucial part for optimum regeneration and maximum gains. Therefore, many “before-bed” supplements can be found. Hops (Humulus lupulus) is mostly added to such bodybuilding supplements due to its claimed sedative effects. There are some other possible uses which we will also discuss.
H. Schiller and assistants  aimed to evaluate sedating activity of Humulus lupulus (ethanolic and CO2) extract. They reported reduced the spontaneous locomotor activity, increased sleeping time and reduced body temperature which confirms central sedating effect. Sedating and anxiolytic activity was attributed to three constituents of hops extract that clearly contributed to the sedating activity: alpha-bitter acid (proved to the be most active constituent), beta-bitter acid and hop oil.
The same was noted by Shishehgar and Monadi  who compared various Humulus lupulus extracts with diazepam (medication usually prescribed to relieve anxiety, muscle spasms, and seizures) in the animal models. They concluded that Humulus lupulus has more sufficient sedative and pre-anesthetic effects than diazepam.
It is suggested that more research is done in order to better understand sedative and anxiolytic effects of this plant.
Herbal products such as valerian (Valeriana officinalis L.) and hops are widely marketed as natural sleep aids and can often be found together in a supplement. Valerian is known to produce a mild sleep-inducing effect . Most studies indicate that a valerian-hops combination produces a mild hypnotic effect in the treatment of insomnia as well as reduces sleep latency [5-7].
Hops (Humulus lupulus) increases GABA levels in rat brain homogenate by inhibiting GABA transaminase . Zanoli et al.  have investigated the in vivo and in vitro effect of hop beta-acids on central nervous system function and suggested an antidepressant-like activity. Behavioral effects of beta-acids fraction were explained by a reduction in the GABAergic activity .
Hops on for Weight Loss via Gastric Juice Secretion
Humulus lupulus can also be found in weight loss supplements. It is backed with claims that it helps the stomach produce a larger volume of gastric juices that aid in digestion. Kurasawa and colleagues  investigated the pharmacological effect of Humulus lupulus (hops) on gastric juice volume and acidity in animal models. They reported orally administered hops produces dose-dependent gastric juice secretion without affecting acidity. It was suggested that gastric juice secretion is mediated via the cholinergic nervous system.
Other Possible Uses for Hops
Humulus lupulus has been traditionally used as diuretic and is often regarded as such. However, no scientific data is available to confirm that claim.
Hops Side Effects
Hops is likely safe and no serious side effects are noted in the literature.
Ohayon, Maurice M. “Epidemiology of insomnia: what we know and what we still need to learn.” Sleep medicine reviews 6.2 (2002): 97-111.
Schiller, H., et al. “Sedating effects of Humulus lupulus L. extracts.” Zeitschrift für Phytotherapie 30.2 (2009): 58-64.
Shishehgar, Ramin, and Alireza Monadi. “Study of Sedation and Pre-Anesthetic Effects of Polar, Semi-Polar and Non-Polar Fractions of Hop (Humulus lupulus L.) Extract Compared with Diazepam in Rats.” Middle-East Journal of Scientific Research 16.6 (2013): 762-768.
Stevinson, Clare, and Edzard Ernst. “Valerian for insomnia: a systematic review of randomized clinical trials.” Sleep Medicine 1.2 (2000): 91-99.
Koetter, U., et al. “A randomized, double-blind, placebo‐controlled, prospective clinical study to demonstrate clinical efficacy of a fixed valerian hops extract combination (Ze 91019) in patients suffering from non‐organic sleep disorder.” Phytotherapy research 21.9 (2007): 847-851.
Morin, Charles M., et al. “Valerian-hops combination and diphenhydramine for treating insomnia: a randomized placebo-controlled clinical trial.” Sleep-New York then Westchester – 28.11 (2005): 1465.
Dimpfel, W., and A. A. Suter. “Sleep improving effects of a single dose administration of a valerian/hops fluid extract. A double-blind, randomized, placebo-controlled sleep-EEG study in a parallel design using the electrohypnogram.” Zeitschrift für Phytotherapie 29.S 1 (2008): P06.
- Awad, R., et al. “Effects of traditionally used anxiolytic botanicals on enzymes of the gamma-aminobutyric acid (GABA) system.” Canadian journal of physiology and pharmacology 85.9 (2007): 933-942.
- Zanoli, P., et al. “Evidence that the β-acids fraction of hops reduces central GABAergic neurotransmission.” Journal of ethnopharmacology 109.1 (2007): 87-92.
Kurasawa, Takashi, et al. “Effect of humulus lupulus on gastric secretion in a rat pylorus-ligated model.” Biological and Pharmaceutical Bulletin 28.2 (2005): 353-357.