Guide
Hops side effects
Sedation is hops' most consistently described effect. In small human appetite trials, a concentrated bitter hop extract also caused loose stools, heartburn, and mild-to-severe gastrointestinal discomfort in some participants, and allergy is described as rare but documented.
Sedation is hops' most consistently described effect, and it's the basis for most of the safety cautions around it. In human appetite trials, a concentrated bitter hop extract also caused digestive side effects — loose stools, heartburn, and in one case gastrointestinal discomfort ranging from mild to severe — in a minority of participants.
Sedation
A national reference database describes hops as generally associated with sedation (PMID 30000893). That's consistent with hops' traditional use and with lab research on how its compounds interact with calming brain chemistry (see what is hops? A plain guide), though we found no human trial that quantified how often drowsiness occurs or how strong it is from hops taken on its own. If you notice drowsiness, avoid driving or operating machinery until you know how it affects you.
Digestive side effects, from the appetite trials
The clearest human side-effect data comes from trials testing a concentrated bitter hop extract for appetite, not from sleep-focused research. A 2022 trial giving 19 men a single 500 mg dose found small but statistically significant increases in gastrointestinal discomfort — nausea, bloating, abdominal discomfort — compared with placebo, with symptoms ranging from mild to severe specifically when the extract was delivered directly to the stomach rather than further down the digestive tract (PMID 35102364). A 2024 trial in 30 women testing lower doses (125-250 mg) recorded a smaller number of side effects: two reports of loose stools and one of heartburn at the higher dose, and one report of loose stools at the lower dose (PMID 39071168). These are doses and a delivery method specific to an appetite-research extract, not necessarily representative of every hops product on the market — see how to choose a good hops for how forms differ.
Allergy
A national reference database describes allergy to hops as occurring rarely (PMID 30000893). A published case report describes one instance of contact urticaria (hives) after hops exposure, in a person who had previously reacted to peanut, chestnut and banana — a pattern some allergists associate with cross-reactivity between certain plant proteins (PMID 11918619). That's a single documented case, not a rate, but it's a reason to introduce any new hops product cautiously if you have a history of food or plant allergies. Stop and see a doctor if you notice hives, swelling, or difficulty breathing.
Vivid dreams and next-day grogginess: common questions, no direct data
Both come up often in searches about hops, but no trial we reviewed measured either one as an outcome specifically for hops. That doesn't rule either out as something some people notice — it means there's no rate or mechanism from the research reviewed here to report.
Questions people ask
Does hops extract have side effects?
Yes. Sedation is the most consistently described effect. In human trials testing a concentrated extract for appetite, some participants also reported loose stools, heartburn, or gastrointestinal discomfort, and allergy is documented as rare.
Does hops extract make you sleepy?
It's described as sedating in a national reference database, consistent with its traditional use and lab-level mechanism research. No human trial we found measured how often or how strongly that happens from hops on its own.
Can hops extract upset your stomach?
In appetite trials testing a concentrated bitter hop extract, some participants reported loose stools, heartburn, or other gastrointestinal discomfort, more often at higher doses and with stomach-targeted (rather than lower-gut) delivery.
Can you be allergic to hops?
Yes, though it's described as rare. A published case report describes hives from hops contact in someone with a history of other plant- and food-related allergic reactions. Stop and see a doctor if you notice hives, swelling, or trouble breathing.
Related reading: who should not take hops?, hops and medications: what to check, and how much hops should you take a day?
Sources
- Hops A national reference database describes hops as containing bitter acids, flavonoids, phytoestrogens and essential oil, notes its GRAS food status, and describes sedation as a known effect and allergy as rare.
- An extract of hops (Humulus lupulus L.) modulates gut peptide hormone secretion and reduces energy intake in healthy-weight men: a randomized, crossover clinical trial A 2022 randomized crossover trial found a single 500 mg dose of a bitter hop extract reduced how much food 19 healthy-weight men ate at their next meal, alongside changes in appetite-related gut hormones, though it also caused more gastrointestinal discomfort than placebo and didn't change how hungry people said they felt.
- Gastrointestinal delivery of bitter hop extract reduces appetite and food cravings in healthy adult women undergoing acute fasting A 2024 randomized crossover trial found a bitter hop extract, taken twice during a 24-hour fast, reduced appetite and food cravings in 30 women at both a 125 mg and 250 mg dose, with a few reports of loose stools or heartburn, mostly at the higher dose.
- Contact urticaria from hops (Humulus lupulus) in a patient with previous urticaria-angioedema from peanut, chestnut and banana A published case report describes a hives-type allergic skin reaction to hops in a person who had previously reacted to peanut, chestnut and banana.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.