Berberine

A plant alkaloid, best known as the supplement taken for blood sugar.

People take it for

Blood sugar
Weight and waist size
Cholesterol and blood fats
Inflammation markers
Hormones and cycles

A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.

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What is berberine?

Berberine is a plant alkaloid found in the bark and roots of a number of plants, several of them long used in Chinese herbal medicine. Reviews credit it with a wide range of effects, but the research that reaches the shelf is almost all about how the body handles sugar and fat. It is sold as capsules and tablets, nearly always as berberine hydrochloride, with a newer version, dihydroberberine, beside it. What is unusual is that much of its research sets it against the medicines prescribed for the same measurements rather than against a dummy capsule.

Why do people take berberine?

Blood sugar

The thinking. Blood sugar is far and away the commonest reason people buy berberine, usually after a fasting reading or an HbA1c that has crept up. The idea is that it works on the machinery a meal uses: reviewers describe it prompting the pancreas to release insulin, and mainly when blood sugar is already high.

What research has found. Trials measured fasting blood sugar, HbA1c and the reading two hours after a sugary drink, mostly in adults with type 2 diabetes. Pooled across thousands of people, fasting sugar came down by about 0.5 to 0.8 mmol/L and HbA1c by roughly half a percentage point; against the tablets usually prescribed for the same readings, berberine came out much the same. A fair body of trials has looked at this, and most point the same way.

Weight and waist size

The thinking. Weight is the second reason people reach for berberine, usually as part of the same tidy-up as the blood sugar rather than on its own. The thinking is that whatever steadies blood sugar also steadies how fat is stored, and reviews do list effects on fat metabolism beside the sugar ones.

What research has found. Three pooled analyses drew on much the same small pile of trials and measured weight, body mass index and waist. They disagree: one found body mass index and waist down while weight did not move, a second found weight down by around two kilograms, and a third, which took in trials of the whole barberry plant, found only a smaller waist-to-hip ratio. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.

Cholesterol and blood fats

The thinking. Cholesterol is the third reason people take berberine, often when a blood test has come back borderline and the same appointment flagged blood sugar too. The thinking is that one set of chemistry sits behind both numbers, which is why trials measuring sugar tend to measure fats at the same visits.

What research has found. Reviews pooled placebo-controlled trials and measured triglycerides, total and LDL cholesterol. Triglycerides came down most consistently, with total and LDL following and HDL a little higher; reviewers noted that courses of up to about three months moved the cholesterol measures more clearly than longer ones, at around a gram a day. Research here is still young: a few studies so far, mostly pointing the same way.

Inflammation markers

The thinking. A smaller group take berberine with inflammation in mind, usually alongside the metabolic reasons rather than instead of them. The thinking is that raised markers travel with extra weight and high blood sugar, so the researchers measuring one measured the others.

What research has found. Trials measured inflammation markers in the blood, C-reactive protein among them, in adults who often carried extra weight or a metabolic condition. Pooled, the markers came down, and one analysis found the change in two of them at daily amounts under a gram and within about five weeks; its authors noted the trials were small and varied a good deal. This is one of the best-studied uses, and several reviews of trials broadly agree.

Hormones and cycles

The thinking. Berberine is also taken by women with polycystic ovary syndrome, for periods that come rarely and the testosterone readings beside them, often after reading about it next to inositol. The thinking is the insulin one again: the idea that puts berberine in the blood sugar aisle is what put it into this research.

What research has found. One comparison of twenty-two trials in just over a thousand women set berberine beside three other insulin-sensitising options and measured how often periods came, testosterone and insulin resistance. Its summary gives figures for the other options rather than for berberine. Few studies have measured this yet, so there is little to go on either way.

What does berberine do in the body?

Berberine is an alkaloid, one of the bitter compounds plants make in their bark and roots, and very little of what you swallow reaches the bloodstream. Reviews are blunt about it: berberine is broken down heavily on the way through, so the amount circulating stays extremely low even after a large dose.

One answer researchers give is that a good deal happens before absorption. Reviews describe berberine changing the mix of bacteria in the gut while those bacteria change berberine, so what does get through is partly a set of related compounds carrying similar activity. The effects then traced are on the handling of sugar and fat: how insulin is released, how readily cells take sugar in, how fats are processed. One trial team linked the blood sugar change in their volunteers to a shift in a single gut bacterium.

What do people say about taking berberine?

These are anecdotes people have shared, not evidence.

What people like

Very commonly, a quieter appetite and less snacking within a week or two, which is what keeps most of those who stay on it going.
Often, a few pounds off over the first weeks, though usually alongside low-carb eating or a fasting window rather than on its own.
Among those watching blood sugar, several describe fasting readings and HbA1c coming down over one to three months.
A minority who could not get on with the prescribed tablet say this sits more easily with them, and mention steadier digestion.

Common complaints

Very commonly, wind, bloating and stomach ache in the first days; several stopped over it, and a few found it worse than the tablet.
Across the threads, a good number took it for weeks or months and saw no change at all in weight, appetite or readings.
Some report looser or more frequent bowels and others the opposite, and a minority nausea strong enough to give up.
A few question whether the quieter appetite was real or expectation, and several say it did nothing about large or sweet meals.

How people take it

500 mg two or three times a day is much the commonest pattern, taken just before or with meals.
Very commonly, with food rather than on an empty stomach, which several say settled the stomach trouble of the first week.
Most say to give it one to three months before judging it, and several build up from a single capsule a day.
Often taken alongside low-carb eating or fasting, and sometimes beside inositol, chromium or a fibre supplement.

Read from these public discussions:

Berberine for weight loss (Mumsnet, 2022)
Does anyone use Berberine? (Mumsnet, 2023)
Berberine (Mumsnet, 2025)
Talk to me about your experience of taking berberine only (Mumsnet, 2026)
Berberine (Diabetes Forum, 2023)
Type 2 berberine supplements (Diabetes Forum, 2024)

What forms of berberine are there?

Form	What’s different	Per serving, on products we list
Berberine HCl	The hydrochloride salt of the alkaloid, and the form nearly every trial used; poorly absorbed.	1.14 g
Dihydroberberine	A newer version of the same alkaloid, developed to get more of it into the blood.	not in our price tables yet

What else is worth knowing about berberine?

Labels give the berberine per serving, and a serving is often two or three capsules; trials used 500 mg two or three times a day.
Stomach and bowel upset is the side effect trials report: one large trial found more of it than with a dummy capsule, though several reviews found no rise in unwanted effects overall, or in low blood sugar.
One review found the fall in fasting blood sugar larger in women than men, in people with diabetes and in Asian participants, and said those comparisons still need repeating.
Very little swallowed berberine reaches the blood, which is why dihydroberberine exists: in a five-person crossover trial, 100 mg of it put more into the blood over two hours than 500 mg of berberine.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

The research behind this page (22 studies)

How much does berberine cost?

That depends on the form and the pack, so we work out the price of the same dose of every berberine product we can find and rank them.

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