Citrus Bergamot

What Citrus Bergamot is

The bergamot grows almost exclusively in Calabria, in the far south of Italy. The peel provides the oil for Earl Grey tea and perfume; the juice is bitter and was long regarded as waste. It was in this very juice that chemists at the University of Calabria described two molecules in 2009 that hardly occur anywhere else: brutieridin and melitidin.

What is sold is an extract made from it, usually as a polyphenol fraction or as a standardized flavonoid extract. The preparations differ considerably in manufacturing and content, which makes it difficult to compare the studies.

Where the nickname “natural statin” comes from

Brutieridin and melitidin carry a chemical appendage that resembles the building block on which the cholesterol-producing liver enzyme works — the same enzyme that statins block. The discoverers therefore called their work statin-like principles of bergamot. This title became the sales slogan.

The claim was tested in 2021 at the University of Illinois at Chicago, in liver and intestinal cells. Result: neither the extract nor any of the five main constituents inhibited the enzyme directly. The extract did reduce the amount of the enzyme in the cells via a different signaling pathway, and brutieridin slowed cholesterol uptake in the intestinal cell model. The authors write explicitly that the mechanism differs from that of statins. This is cell culture — in humans, the mechanism has not been studied at all.

Why the origin of the studies matters

The studies with the big numbers almost all come from Catanzaro in Calabria, from a research group led by the same researcher. He is named as the inventor on the patent for exactly this extract, filed in 2008 and granted in 2014; the holder is the company that manufactures it. That does not make the results wrong, but it does make them in need of confirmation.

Further work by the same group followed: 77 patients in 2013, without blinding, and 60 people with diabetes, with employees of an extract manufacturer as co-authors. As soon as measurements are taken outside this group and against placebo, the effect shrinks considerably.

What the studies show

Mollace 2011 — the original study

237 patients with elevated blood lipids, 30 days of the bergamot polyphenol fraction. At the higher dose, LDL fell by almost 39 percent and total cholesterol by 31 percent, while HDL rose by 39 percent. These are the numbers on the packages. They do not appear in the abstract of the paper itself, and the first author is the patent holder of the extract tested.

Toth 2016 — Palermo, without a control group

80 people with moderately elevated cholesterol took an extract with 150 milligrams of flavonoids for 6 months. LDL fell by just under 20 percent, and the wall thickness of the carotid artery decreased from 1.2 to 0.9 millimeters, that is, by a quarter in half a year. The catch: all participants received the extract, and the comparison was with their own baseline. No one has replicated this finding.

Cai 2017 — Shanghai, double-blind against placebo

98 older adults, 12 weeks, randomized and double-blind. At the end, LDL was 3.13 versus 3.43 millimoles per liter under placebo, a difference of just under 9 percent. Significant, but 9 and not 39. It is the cleanest efficacy study outside Italy, but it too is not entirely independent: one co-author comes from industry.

Stonehouse 2025 — Australia, no effect

A government-funded Australian research institute, commissioned by a manufacturer, tested a combination containing bergamot extract against placebo in 42 people over 4 months. There was no difference in LDL. To be fair: bergamot was only one component here, and the dose was lower than in the Calabrian studies.

Meta-analyses — consistent in direction, not in size

A network meta-analysis of 131 studies ranked bergamot in 2022 as the most effective plant-based cholesterol remedy, with 1.21 millimoles per liter less LDL — and states in the same abstract that the evidence rests on a relatively small group of studies and requires further investigation. A second meta-analysis of 14 studies arrives at 55 milligrams per deciliter less LDL and calls the results inconsistent. A Spanish review found LDL reductions between 7.6 and 40.8 percent across 12 papers — a range that mainly shows that the studies do not measure the same thing.

Where the number comes from — and where it does not

The advertised order of magnitude is unconfirmed. Since 2011, no blinded study outside this research group has reproduced the Calabrian effect sizes; where others have measured, just under 9 percent or nothing at all remained. The range of 7.6 to 40.8 percent across twelve papers is not a measure of dispersion but an indication of very different preparations and methods.

The second, larger gap concerns the endpoints. For statins, it has been shown across around 170,000 patients that for every millimole per liter less LDL, major vascular events decrease by 22 percent. For bergamot, there is not a single study with heart attack, stroke or mortality as an endpoint. A laboratory value is lowered, and the hope is that the rest will follow. For a sense of scale: a high-dose statin lowers LDL by 50 to 60 percent.

Status, approval and legal

In Germany, bergamot extract is a food supplement, not a medicine. So there is no approval procedure, no official review of efficacy and no authorized health claim relating to cholesterol. Accordingly, the studies use different products: anyone comparing numbers on the package with study results is often not comparing the same preparation.

Safety

The studies themselves report hardly any side effects, but they were small and short — 30 days to 6 months. One point does not appear in the advertising: bergamot juice contains bergamottin, named after the fruit and one of the substances that, in grapefruit juice too, block a liver enzyme through which many medicines are broken down, including some statins. 18.2 milligrams per liter were measured in the juice. Whether the capsules contain enough of it to shift the level of a statin taken at the same time has not been studied in any human study. The oil from the peel also contains phototoxic furocoumarins, which, on the skin together with sunlight, can trigger pigment spots, known as berloque dermatitis. For the patented juice extract, it is described that these substances are largely removed; for other capsule products, data are lacking. This is not medical advice: anyone who wants to lower their LDL should discuss this with a doctor.

Sources

• Di Donna et al., J Nat Prod 2009
• Mollace et al., Fitoterapia 2011
• Toth et al., Front Pharmacol 2016
• Cai et al., Lipids Health Dis 2017
• Stonehouse et al., Atherosclerosis 2025
• Osadnik et al., Pharmacol Res 2022
• Lamiquiz-Moneo et al., Crit Rev Food Sci Nutr 2020
• Huang et al., Nutrients 2021
• Chambari et al., Food Sci Nutr 2026