Matured hop extract safety tests in rats and lab cells
What it found
In rats, matured hop extract caused no deaths or signs of harm over 90 days at doses up to 4,022 mg/kg body weight per day.
Lab cell tests showed some chromosome changes at high concentrations, but tests inside living rats did not.
What they found
Animal and lab studies
Chromosome changes in lab cells
When hamster lung cells were exposed to 3,330 or 5,000 μg/mL of the extract without metabolic activation, structural chromosome changes appeared. A test with added metabolic activation at 5,000 μg/mL gave a false positive result.
No DNA damage in rats
Rats given up to 2,000 mg/kg body weight of the extract showed no chromosome damage in their bone marrow. Bacteria tests also found no gene mutations with or without metabolic activation.
Single large dose in rats
Ten male and ten female rats each received one oral dose of 2,000 mg/kg body weight. Over 14 days of observation, no deaths or harmful signs were recorded, and body weights stayed normal.
90-day feeding study in rats
Rats ate diets mixed with 1.25%, 2.5% or 5.0% extract for 90 days. This delivered up to 3,484 mg/kg body weight per day for males and 4,022 mg/kg body weight per day for females. No deaths, weight changes, or organ damage were seen.
Minor blood and urine shifts
A few small differences appeared in urine potassium, urine protein, white blood cell counts and organ weights compared to controls. The authors judged these to be normal background variation rather than harm from the extract.
What the authors conclude
- They conclude that matured hop extract showed no gene damage potential in living animals, even though lab cell tests flagged chromosome changes at high doses.
- They state that the highest amount causing no observed harm was over 3,484 mg/kg body weight per day for male rats and over 4,022 mg/kg body weight per day for female rats.
- The authors say these results point to no safety concern for matured hop extract under the conditions of their preclinical study.
How it was done
Earlier work showed that taking matured hop extract reduced body fat in animals and people. The authors wanted to check its safety before it was used more widely, because no preclinical safety studies had been reported yet.
They tested matured hop extract on bacteria, hamster lung cells in the lab, and rats. They gave a single dose of 2,000 mg/kg body weight to 10 male and 10 female rats and watched them for 14 days. They also fed 40 male and 40 female rats diets containing 1.25%, 2.5% or 5.0% of the extract for 90 days.
What it can’t tell you
- All the dosing and long-term feeding tests were done in rats, so they cannot show what happens in people who eat products containing this extract.
- Lab cell tests use very concentrated amounts applied directly to cells, which does not match how a person would take in the ingredient through food.
Who paid
- Authors work at
- Research Laboratories for Health Science and Food Technologies, Ltd; Central Laboratories for Key Technologies, Ltd
The paper
- Title
- Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Suzuki S, Morimoto-Kobayashi Y, Takahashi C, Taniguchi Y, Katayama M (2018). Genetic, acute and subchronic toxicity studies of matured hop extract produced by extraction from heat-treated hops. The Journal of toxicological sciences. doi:10.2131/jts.43.473Free full textPubMed 29973479DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error