Calocurb (Amarasate) review

Our take: the science is real and the arithmetic is brutal

We have reviewed a lot of products that borrow the letters GLP-1 and have nothing behind them. This is not one of them, and it deserves to be said clearly before any criticism: Calocurb is the only supplement in this category we have found with randomised controlled human trials measuring both the hormones it claims to move and the weight it claims to shift.

The active is Amarasate, a bitter extract of New Zealand hops, delivered in a delayed-release capsule designed to survive the stomach and reach the small intestine. There it activates bitter taste receptors — the same receptor family found on the tongue — which trigger release of GLP-1, CCK and PYY. That mechanism is not a marketing metaphor; it has been measured in people, in a crossover trial published in the American Journal of Clinical Nutrition.

It also does something almost nothing else on this site does: the dose on the label is the dose in the studies. Four capsules a day is 500 mg of Amarasate, which is exactly what the trials used. That earns the highest dose score we have given.

Then the price. At the label's own target dose, the 90-capsule bottle lasts 22 days rather than the month the packaging claims, which puts the real cost at about $4.00 a day — the most expensive product we have reviewed, by some distance. The 24-week trial found 3.77 kg of weight loss against 0.40 kg on placebo. Whether 3.4 kg of difference is worth roughly $1,460 a year is a judgement, not a fact, and it is the judgement this whole review comes down to.

This is a desk review of a published label and the research behind the ingredient. Nobody here has taken this product.

What is in the capsule, and what the label tells you

A serving is two capsules and contains 250 mg of Amarasate (New Zealand hops flower extract) — 125 mg per capsule. The bottle holds 90 capsules, which the label describes as 45 servings and approximately one month's supply. The other ingredients are canola oil, rosemary leaf extract, and a delayed-release vegetarian capsule of hypromellose. That is the entire formula: one quantified active and three functional excipients.

By the standards of this aisle that is an excellent label. The active carries a number, nothing hides in a proprietary blend, the delivery system is explained rather than mystified, and both the titration schedule and the daily ceiling are printed.

The directions are specific: "Adults take 1 capsule per day for the first 48 hours. After 48 hours, take 2 capsules, twice daily at least 4 hours apart. Do not exceed 4 capsules per day." The brand suggests taking them on an empty stomach, about an hour before a meal. A slow start on a bitter gut-acting compound is sensible, and publishing a maximum is more than most brands bother to do.

The arithmetic problem with "one month"

Here is where the label contradicts itself, and it is worth doing slowly because it changes the price of the product by a third.

The target dose the label builds you up to is two capsules twice daily — four capsules a day. The bottle contains 90 capsules. Ninety divided by four is 22.5 days.

The "45 servings, approximately 1 month" figure is arrived at by counting a serving as two capsules and then quietly assuming you take one serving a day. But the label's own instruction is to take two servings a day after the first 48 hours. Both numbers are printed on the same product, and they cannot both describe how you are meant to use it.

The consequence is financial. At $89.99 a bottle and 22.5 days of use, the cost is $4.00 a day, or roughly $122 a month, not $89.99. Subscription pricing takes about 15 per cent off, which brings it to roughly $3.40 a day. For comparison, the sales-page supplements we have reviewed run $1.63 to $2.97 a day, and a well-evidenced vitamin D costs six cents.

We are not accusing anyone of dishonesty — "servings per container" is a defined labelling term and 45 is arithmetically correct for it. But a reader budgeting from the front of the bottle will be out by a third, and the brand knows what dose it is telling people to take.

The evidence, trial by trial

This is the part that separates Calocurb from everything else in the category, so it is worth going through properly rather than accepting a "clinically studied" badge.

The mechanism trial

The key paper is Walker and colleagues, published in the American Journal of Clinical Nutrition in 2022. Nineteen healthy-weight men completed a randomised, double-blind, three-treatment crossover with a week between treatments: placebo, 500 mg of hops extract in delayed-release capsules, or 500 mg in quick-release capsules.

Both active treatments significantly reduced ad libitum energy intake — by about 911 to 944 kJ, roughly 220 kcal — against placebo. Both significantly increased post-prandial CCK, GLP-1 and PYY. That is the claim tested directly, in people, with the hormones measured rather than assumed. It is a small, acute, single-sex study, and it is still better evidence than any competitor in this aisle has produced.

The fasting and women's trials

An earlier 2019 study put 30 men through a 24-hour water-only fast and reported reduced hunger with the extract. A 2024 study repeated the acute design in 30 women. Both are small, both are short, and both come from the same research programme.

The weight trial

The 24-week C4 trial is the one the marketing leans on, and it is the most substantial. It randomised 150 adults with a BMI of 25 to 35 in a double-blind placebo-controlled parallel design, with 128 completing. Reported in Obesity Pillars in July 2026, it found participants on Amarasate lost 3.77 kg against 0.40 kg on placebo — about 4.3 per cent of body weight — with lean mass preserved and the loss coming from fat including visceral fat.

Three caveats belong with that figure, and none of them cancels it. Both arms received diet and exercise advice, so this is a supplement added to a programme rather than a supplement alone. The research originates with the New Zealand institute that developed Amarasate and licenses it commercially, which is a real interest to declare. And we could not open the paper itself — PubMed and the publisher both refused our requests — so the trial figures here come from the institute's own announcement and trade reporting of it, which is a weaker chain of custody than we would like.

What the numbers mean next to the drugs

Semaglutide produced about 15 per cent weight loss in STEP 1 and tirzepatide 20.9 per cent in SURMOUNT-1. Calocurb's 4.3 per cent is roughly a quarter of that. Our GLP-1 explainer charts the four figures to scale, and the picture is the honest summary: this is a real effect at a much smaller size, not a substitute for a prescription and not nothing.

The claims on the page, checked

"9x more weight loss than willpower alone over 6 months." Arithmetically true and rhetorically generous: 3.77 kg divided by 0.40 kg is about 9.4. Multiplying two small numbers produces a large multiple. The absolute difference is 3.4 kg over six months, which is the figure that matters to a buyer.

"Reduce hunger by 30%, cravings by 40% and calorie intake by 18%." These come from the acute trials, where the effects were measured over hours rather than months. They describe what happens after a dose, not what happens to your weight over a year.

"Works in as little as one hour, with fullness lasting 4-6 hours." Consistent with a delayed-release capsule reaching the small intestine and the hormone responses measured in the crossover trial.

"15 years clinical research in humans." Defensible as a description of the research programme, though it should be read as four published human studies rather than fifteen years of continuous trials.

Side effects, and one sentence we would change

The brand discloses what to expect, which is to its credit: "In the first 24-48 hours some people may experience a mild laxative effect, cramps and indigestion or hop tasting burps." That is a straight description of what a bitter gut-acting compound does, and publishing it rather than burying it is the right instinct.

The sentence that follows is not: "Just like any other detox - it's a spring clean for your body!" There is no detox here and nothing is being spring-cleaned. A product with genuine trials behind its actual mechanism does not need to reach for the vocabulary of products that have none, and the contrast between that line and the AJCN paper is jarring.

The product is not tested in anyone under 18, or in women who are pregnant or breastfeeding, and should be avoided by all three groups. No serious drug interactions are established, but if you take regular medication — particularly anything where absorption timing matters, since this is designed to slow gastric emptying and is taken on an empty stomach — raise it with a pharmacist first.

One number worth weighing: the Amazon listing shows a 3.7 rating across 528 reviews, which is low for a supplement. Marketplace ratings measure satisfaction rather than efficacy and blend delivery and price complaints with everything else. But for a product whose main acute effect is gastrointestinal, a mediocre rating on a large sample is at least consistent with tolerance being a genuine issue for a meaningful share of buyers.

Who this is actually for

There is a narrow but real case for this product, and it is worth stating precisely because most coverage either dismisses it or oversells it.

It makes sense for someone who cannot access a GLP-1 prescription — ineligible, unable to afford it, or unwilling to inject — who has the disposable income for roughly $1,460 a year, and who understands they are buying about a quarter of the drug effect. It makes sense for someone whose specific problem is appetite and snacking rather than portion size, because the measured effect is on hunger and ad libitum intake.

It does not make sense as a cheaper route to the same result, because it is not cheaper than anything except the drugs and does not produce the same result. And it makes no sense at all for someone who has not first tried the free interventions the trial participants also received, since both arms of the C4 trial got diet and exercise advice.

Sources and shopping: what to check

Before ordering, do the division yourself: capsules in the bottle, divided by the daily dose you intend to take, gives the days of supply and therefore the real cost. If you plan to follow the label to four capsules a day, budget for a bottle every three weeks.

Check whether a subscription is genuinely cheaper for you at that consumption rate, and read the cancellation terms before starting one. And if you are considering this because you cannot get a prescription, it is worth one conversation with a doctor first to confirm that is actually true — eligibility criteria in several countries have widened.

Our commercial link is our Calocurb link. It earns a commission at no extra cost to you and has not moved the 6.6 above — a score built from the highest dose-accuracy mark we have given and the lowest value mark on any product we would otherwise recommend.

The fair summary: this is what a supplement looks like when a company actually does the research. It is also $4 a day for 3.4 kg over six months. Both of those things are true, and which one decides it depends entirely on your budget.