Benefits
Total and LDL cholesterol levels
In an 8-week study, adults with high cholesterol who took 400 mg of naringin a day had total cholesterol about 14 percent lower and LDL cholesterol about 17 percent lower, while healthy volunteers on the same dose saw no change. A 90-day trial in 28 people with dyslipidemia also reported lower total and LDL cholesterol. A larger trial in 204 people found no change in cholesterol, so the human evidence is not consistent.
Body weight, lipids and adiponectin levels
In a 90-day double-blind trial, 28 adults with dyslipidemia who took 450 mg of naringin a day had a lower body mass index, lower total and LDL cholesterol and higher blood levels of adiponectin, a hormone made by fat tissue, than people on placebo. This was a single small trial, and triglycerides and HDL cholesterol were not changed in the cholesterol studies.
Antioxidant enzyme activity in red blood cells
In the 8-week cholesterol study, people with high cholesterol who took naringin had higher activity of two antioxidant enzymes in their red blood cells, superoxide dismutase and catalase. A third enzyme, glutathione peroxidase, and a marker of fat oxidation in the blood did not change, and none of these measures changed in healthy volunteers given the same dose.
Fat and sugar handling in laboratory and animal research
Most of the detailed work on how naringin affects fat storage, blood sugar and inflammation comes from cell and animal studies. In those models naringin lowered fat building in the liver, improved insulin signaling and reduced inflammatory signaling. These findings have not been confirmed as health outcomes in people and should be read as background, not proof of an effect.
Mechanism of action
Released as naringenin by gut bacteria
Naringin is a glycoside, meaning naringenin with two sugars attached, and it is poorly absorbed on its own. Bacteria in the large intestine remove the sugars and release naringenin, the aglycone, which is then absorbed and processed by the liver. This is why naringin and naringenin are related but behave differently in the body.
Inhibits intestinal OATP transporters and CYP3A4
In human studies, naringin blocks an intestinal uptake transporter called OATP1A2, which lowered blood levels of the allergy drug fexofenadine. Naringin and grapefruit can also inhibit the CYP3A4 enzyme in the gut wall that breaks down many drugs, although grapefruit contains other compounds that drive much of that effect. The result can be higher or lower drug levels depending on the medicine.
Lipid and antioxidant enzyme signaling in preclinical models
In cell and animal studies, naringin reduced the liver's production of cholesterol and fatty acids and raised the activity of natural antioxidant enzymes such as superoxide dismutase and catalase. Related pathways studied include AMPK and PPAR-alpha. How much of this happens at supplement doses in people is not established.
Clinical trials
Double-blind, randomized, placebo-controlled trial of 450 mg/day naringin for 90 days in adults with dyslipidemia. (Barajas-Vega et al. 2022, Int J Vitam Nutr Res)
28 adults with diagnosed dyslipidemia (14 naringin, 14 placebo).
The naringin group had a lower body mass index, lower total and LDL cholesterol, and higher adiponectin levels than the placebo group. The trial was small, ran for 90 days and did not report whether blood sugar changed.
Controlled 8-week study of 400 mg/day naringin in people with high cholesterol and in healthy controls. (Jung et al. 2003, Clin Nutr)
30 people with high cholesterol and 30 healthy controls, all given 400 mg/day with meals.
In the high-cholesterol group, naringin lowered total cholesterol by about 14 percent and LDL cholesterol by about 17 percent, lowered apolipoprotein B, and raised red-cell superoxide dismutase and catalase activity. Triglycerides, HDL cholesterol, glutathione peroxidase and a fat-oxidation marker did not change, and nothing changed in the healthy controls.
Randomized, placebo-controlled, parallel trial of 500 mg/day naringin or 800 mg/day hesperidin for 4 weeks in adults with moderately high cholesterol. (Demonty et al. 2010, J Nutr)
204 healthy men and women with moderately high total cholesterol (194 completed).
Neither pure naringin nor pure hesperidin changed total cholesterol, LDL cholesterol, HDL cholesterol or triglycerides compared with placebo. This larger, food-company-funded trial did not confirm the lipid-lowering seen in the smaller studies.
Randomized crossover pharmacokinetic study of fexofenadine taken with a naringin solution, grapefruit juice or water. (Bailey et al. 2007, Clin Pharmacol Ther)
12 healthy volunteers.
A naringin solution cut the amount of fexofenadine absorbed to about 75 percent of the water value, and grapefruit juice cut it to about 55 percent. The authors concluded that naringin directly blocks the intestinal OATP1A2 transporter, the first report of a single dietary compound changing drug transport in people.
Randomized four-way crossover study of felodipine taken with grapefruit juice, its fractions, a naringin-rich fraction or water. (Bailey et al. 1998, Clin Pharmacol Ther)
12 healthy men.
Grapefruit juice raised felodipine blood levels the most. The naringin-rich fraction raised them less than whole juice, so naringin contributes to but is not the main cause of the grapefruit and felodipine interaction, which mostly involves CYP3A4 inhibition by other grapefruit compounds.
Controlled, randomized crossover study of 6 days of high-dose naringin capsules before a dose of talinolol. (Nguyen et al. 2015, Eur J Pharm Sci)
10 healthy volunteers.
About 1,050 mg of naringin taken as capsules did not change the blood levels of talinolol, a drug carried by OATP transporters. The authors noted that naringin in capsule form can behave differently from naringin dissolved in grapefruit juice, so drug effects depend on the medicine, the dose and the form.