What is Amarasate? Calocurb's hop extract, claim by claim
What is Amarasate? The New Zealand bitter hop extract inside Calocurb, with each brand claim set against the four human trials we read.
Amarasate is a bitter extract of New Zealand hops (Humulus lupulus) and the active ingredient in Calocurb capsules, sold as an appetite supplement, not a medicine. Its bitter compounds are proposed to act on gut taste receptors. In a 2022 trial of 19 men, one 500 mg dose raised GLP-1, CCK and PYY responses and cut same-day food intake.
Ask what is Amarasate and the brand’s own page answers with three percentages. This is an evergreen explainer: what the extract is, how it is meant to work, and which human trial sits behind each figure the brand prints. This desk read the Calocurb page on GLP-1 and Amarasate and the PubMed abstracts of four trials on 23 September 2026.
What is Amarasate, and who developed it?
The brand calls it a supplement “made from bitter hops flowers grown in New Zealand” and names it as the active ingredient in Calocurb.
The research behind it comes from one group. All four trials read here list Walker as first author. The 2019, 2022 and 2024 papers are from The New Zealand Institute for Plant and Food Research, the 2022 one jointly with the University of Auckland’s Human Nutrition Unit; the 2026 trial lists the New Zealand Institute for Bioeconomy Science. The conflict statements in the 2019, 2024 and 2026 papers say the institute licensed the hop extract to Calocurb Ltd, and the 2024 and 2026 statements add that it holds a minor shareholding in the company.
That is disclosed, not hidden. It is still worth knowing: every trial in this piece comes from the developer’s side.
How does Amarasate work in the body?
The proposed mechanism is a “bitter brake”. Hormone-releasing cells in the gut carry bitter taste receptors, and the 2022 trial in the American Journal of Clinical Nutrition tested whether a hop extract aimed at them changes the signals around a meal.
It did. Against placebo, both a quick-release (gastric) and a delayed-release (duodenal) capsule stimulated post-meal CCK, GLP-1 and PYY responses and pre-lunch ghrelin. Insulin responses fell with no change in blood glucose. Energy eaten at an unlimited lunch and afternoon snack fell from 5,383 kJ on placebo to 4,473 kJ gastric and 4,439 kJ duodenal.
One finding runs against the marketing. The abstract reports no significant treatment effect on any subjective measure of appetite. In that trial the men ate less, but did not rate themselves as significantly less hungry.
Amarasate’s claims against the trials
The brand page says Amarasate has been “clinically proven” to cut hunger, cravings and calorie intake, that it doubles natural GLP-1, and that a 6-month weight study is “underway”. Here is each claim beside the trial nearest to it.
| Brand claim | Nearest trial read | Design, n, dose | What was measured | Gap |
|---|---|---|---|---|
| Hunger down 30% | Nutrients, 2019 | 30 men; placebo, 100 mg or 250 mg twice, late in a 24 h fast | Hunger ratings, 18-24 h of the fast | Significant fall of more than 10% (p < 0.05); abstract gives no 30% |
| Cravings down 40% | Obesity Pillars, 2024 | 30 women, randomised double-blind crossover; 125 mg or 250 mg twice in a 24 h fast | Appetite and cravings ratings | Significant fall (p under 0.05); abstract gives no 40% |
| Calorie intake down 18% | Am J Clin Nutr, 2022 | 19 healthy-weight men, crossover; one 500 mg dose | Food eaten at one lunch and one snack | 16.9% and 17.5% by our arithmetic; one day |
| Doubles natural GLP-1 | Am J Clin Nutr, 2022 | As above | Post-meal GLP-1 response | Rise reported; no size in the abstract |
| 6-month weight study “underway” | C4, Obesity Pillars, 2026 | 150 adults randomised, 128 completed; 500 mg a day for 24 weeks | Body weight and fat mass | Published 17 July 2026 |
The 18% is the claim that lines up best. On the 2022 numbers, the gastric arm ate 16.9% less than placebo and the duodenal arm 17.5% less. The brand page does not say which trial its 18% comes from, so the match is our inference. It was measured over one afternoon in 19 men who were not trying to lose weight.
The fasting studies back the direction of the hunger and cravings claims, not their size. Neither abstract, as read here, states 30% or 40%; the full papers may, and this desk did not read them. Both measured people who had gone without food for most of a day, which is not how most readers would take a capsule. A 2023 paper in Appetite compared delivery routes; we did not read it and report nothing from it.
Does Amarasate cause weight loss?
Only one trial measured weight. The 24-week C4 trial gave 500 mg of bitter hop extract a day, half before each of the two main meals, alongside monthly diet and lifestyle seminars. The extract group lost 3.8% more body weight than placebo and 3.9 kg more fat mass; against their own starting point they lost 4.3% of body weight.
So the study the brand page calls “underway” was published online on 17 July 2026. Its full numbers are in Is Calocurb clinically proven? The C4 trial in numbers, and its dropouts and dose cuts in Calocurb side effects: what the 24-week trial counted. How it compares with a prescription drug’s evidence is in Calocurb vs Ozempic.
On “clinically proven”: four developer-run trials, three of them measuring effects within a single day, is a real evidence base but a small one. We have written before about how much a phrase like ‘clinically studied’ can carry.
This desk read no FDA page this run and makes no claim about Amarasate’s regulatory status in any country.
Amarasate questions, answered
Is Amarasate a GLP-1?
No. Amarasate is a bitter hop extract sold as a supplement, not the GLP-1 hormone and not a GLP-1 receptor agonist drug such as semaglutide or tirzepatide. In the 2022 trial of 19 men, a 500 mg dose increased the body’s own GLP-1 response after a meal compared with placebo. The abstract gives no size for that rise, so ‘doubling’ is the brand’s claim, not a figure we could check.
What are the side effects of Amarasate?
The reported side effects are digestive. In the 2022 trial both capsule types caused small but significant rises in discomfort such as nausea and bloating, with mild to severe symptoms in the quick-release arm only. In the 2024 study of women, loose stools were reported three times across the two doses and heartburn once. The brand page says some people get diarrhea at first and that nausea is rare.
How much Amarasate should you take?
The brand page says to take Calocurb about an hour before eating, starting at one capsule a day and building to two capsules before two meals if needed. The trials used 100 to 250 mg twice during a fast, a single 500 mg dose, and 500 mg a day split before two meals over 24 weeks. We read no label, so we give no per-capsule amount.
The short version
Amarasate is a hop extract with a plausible mechanism, a same-day effect on eating in one small trial, and one 24-week weight result from its developer. None of that is a promise about any one person, and weight is not a measure of anyone’s worth. If you take a GLP-1 medicine, have a gut condition or are pregnant, ask a doctor or pharmacist before adding an appetite supplement. Nothing here has been evaluated by the FDA, and none of it is medical advice.