Naringenin

Pharmacology & Research

Naringenin is the signature flavanone of citrus and the central branch point of the entire flavonoid pathway — the node from which flavones, flavonols and the other flavanones diverge. Its evidence, though, is dominated by two substitutions and one myth. Most human “naringenin” data are really grapefruit / citrus / orange-juice interventions or the glycoside naringin, not the pure aglycone ^{3,6Reference 3Demonty I et al. · 2010The citrus flavonoids hesperidin and naringin do not affect serum cholesterol in moderately hypercholesterolaemic men and womenView study →Reference 6Rendeiro C et al. · 2016RCTFlavanone-rich citrus beverages counteract the transient decline in postprandial endothelial function in humans — a randomised, controlled, double-masked, crossover intervention studyView study →}; naringin is a poorly-absorbed prodrug that gut bacteria cleave to naringenin in the colon ^{11Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →}; and — the myth to retire — the grapefruit–drug interaction is caused by furanocoumarins, not naringin or naringenin ^{13Reference 13Paine MF et al. · 2006A furanocoumarin-free grapefruit juice establishes furanocoumarins as the mediators of the grapefruit-juice–felodipine interactionView study →}. The single thing tested as the pure aglycone for efficacy is one small NAFLD trial ^{1Reference 1Namkhah Z et al. · 2021RCTDoes naringenin supplementation improve lipid profile, severity of hepatic steatosis and probability of liver fibrosis in overweight/obese patients with NAFLD? A randomised, double-blind, placebo-controlled clinical trialView study →}.

1. Metabolic — NAFLD, lipids & glucose

The one genuine pure-aglycone efficacy signal. In a randomised trial, 200 mg/day naringenin for 4 weeks in 44 overweight/obese NAFLD patients significantly improved hepatic-steatosis grade and lowered triglycerides, total- and LDL-cholesterol (with a rise in HDL) ^{1Reference 1Namkhah Z et al. · 2021RCTDoes naringenin supplementation improve lipid profile, severity of hepatic steatosis and probability of liver fibrosis in overweight/obese patients with NAFLD? A randomised, double-blind, placebo-controlled clinical trialView study →}. On the glycoside, a naringin trial (450 mg/day, 90 days) reduced BMI and LDL and raised adiponectin ^{2Reference 2Barajas-Vega JL et al. · 2022Clinical trialNaringin reduces body weight, plasma lipids and increases adiponectin levels in patients with dyslipidaemiaView study →} — but this is directly contradicted by the larger, better-powered pure-naringin trial (n=204) in which naringin (and hesperidin) had no effect on cholesterol ^{3Reference 3Demonty I et al. · 2010The citrus flavonoids hesperidin and naringin do not affect serum cholesterol in moderately hypercholesterolaemic men and womenView study →}. A clean single-ascending-dose RCT (150–900 mg) established naringenin’s safety and dose-proportional exposure but had no efficacy endpoint ^{5Reference 5Rebello CJ et al. · 2020RCTSafety and pharmacokinetics of naringenin — a randomised, controlled, single-ascending-dose clinical trialView study →}; a single-subject case report of raised insulin sensitivity and metabolic rate is suggestive but anecdotal ^{4Reference 4Murugesan N et al. · 2020Naringenin increases insulin sensitivity and metabolic rate — a case studyView study →}.

Gap: the NAFLD trial is tiny, single-centre and only 4 weeks, and the harder endpoints (ALT/AST, fibrosis score) did not improve — a short-term surrogate signal, not proven liver benefit; the naringin lipid data are conflicting, with the larger trial null ^{1,3Reference 1Namkhah Z et al. · 2021RCTDoes naringenin supplementation improve lipid profile, severity of hepatic steatosis and probability of liver fibrosis in overweight/obese patients with NAFLD? A randomised, double-blind, placebo-controlled clinical trialView study →Reference 3Demonty I et al. · 2010The citrus flavonoids hesperidin and naringin do not affect serum cholesterol in moderately hypercholesterolaemic men and womenView study →}.

2. Cardiovascular & endothelial

Citrus flavanones acutely improve postprandial endothelial function ^{6Reference 6Rendeiro C et al. · 2016RCTFlavanone-rich citrus beverages counteract the transient decline in postprandial endothelial function in humans — a randomised, controlled, double-masked, crossover intervention studyView study →}, and hesperidin improves endothelial function and NO in metabolic syndrome ^{7Reference 7Rizza S et al. · 2011Clinical trialCitrus polyphenol hesperidin stimulates production of nitric oxide in endothelial cells while improving endothelial function and reducing inflammatory markers in patients with metabolic syndromeView study →} — but these are hesperidin- or mixture-driven.

Gap: there is no RCT showing that naringenin specifically improves endothelium-dependent vasodilation or blood pressure; the vascular story belongs to the flavanone class and hesperidin, not to naringenin. Attribute accordingly ^{6,7Reference 6Rendeiro C et al. · 2016RCTFlavanone-rich citrus beverages counteract the transient decline in postprandial endothelial function in humans — a randomised, controlled, double-masked, crossover intervention studyView study →Reference 7Rizza S et al. · 2011Clinical trialCitrus polyphenol hesperidin stimulates production of nitric oxide in endothelial cells while improving endothelial function and reducing inflammatory markers in patients with metabolic syndromeView study →}.

3. Anticancer & antiviral (preclinical)

A consistent laboratory literature: naringenin induces apoptosis (Bax/Bak↑, Bcl-2↓, caspase activation) and inhibits NF-κB and JAK2/STAT3 across cancer models ^{8Reference 8Faramarzi S et al. · 2022Meta-analysisNaringenin induces intrinsic and extrinsic apoptotic signalling pathways in cancer cells — a systematic review and meta-analysis of in-vitro and in-vivo dataView study →}, and impairs replication of dengue ^{9Reference 9Frabasile S et al. · 2017The citrus flavanone naringenin impairs dengue virus replication in human cellsView study →} and SARS-CoV-2 ^{10Reference 10Clementi N et al. · 2021In vitroNaringenin is a powerful inhibitor of SARS-CoV-2 infection in vitroView study →} in vitro.

Gap: zero human efficacy trials for any of these — cell and animal only, and naringenin’s poor bioavailability makes the in-vitro-active concentrations hard to reach in people. Score kept in single digits ^{8,10Reference 8Faramarzi S et al. · 2022Meta-analysisNaringenin induces intrinsic and extrinsic apoptotic signalling pathways in cancer cells — a systematic review and meta-analysis of in-vitro and in-vivo dataView study →Reference 10Clementi N et al. · 2021In vitroNaringenin is a powerful inhibitor of SARS-CoV-2 infection in vitroView study →}.

Mechanisms

Target / pathway	Effect	Relevant to	Evidence
PPARα/γ activation; ↑ fatty-acid oxidation, ↓ lipogenesis (SREBP-1c)	improved hepatic lipid handling	NAFLD, lipids	preclinical
AMPK / insulin sensitivity	↓ hepatic glucose output	glucose	preclinical + n=1 human
NF-κB inhibition (↓ TNF-α, IL-6)	anti-inflammatory	metabolic, anticancer	preclinical
Pro-apoptotic (Bax↑, Bcl-2↓, JAK2/STAT3↓)	anticancer	anticancer	in vitro/animal
Weak, reversible CYP3A4 inhibition; OATP1A2/2B1 inhibition	drug interaction — minor CYP; real OATP (reduces some drug uptake)	safety	in vitro + human (OATP) 16,17Reference 16Lu WJ et al. · 2011Enantiomers of naringenin as pleiotropic, stereoselective inhibitors of cytochrome P450 isoformsView study →Reference 17Bailey DG et al. · 2007Naringin is a major and selective clinical inhibitor of organic anion-transporting polypeptide 1A2 (OATP1A2) in grapefruit juiceView study →

Pharmacokinetics

Naringenin’s pharmacokinetics are governed by the sugar it usually arrives with. In food it is almost never the free aglycone — it is stored as naringin (7-O-neohesperidoside) and narirutin (7-O-rutinoside), whose rhamnose-containing disaccharides resist small-intestinal enzymes. Absorption is therefore deferred to the colon, where microbiota strip the sugars to release naringenin — the same colonic-deglycosylation pattern as rutin and hesperidin — giving a long lag and delayed, blunted, highly variable plasma appearance ^{11Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →}. Human data show it: peak plasma naringenin was ~0.6 µmol/L after orange juice and ~6 µmol/L after grapefruit juice, with large inter-individual variation and a short (~1.3–2.2 h) half-life ^{11Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →}. Dosing the aglycone directly bypasses the bottleneck and absorbs faster and higher (135 mg gave Cmax ~7.4 µmol/L) ^{12Reference 12Kanaze FI et al. · 2007Clinical trialPharmacokinetics of the citrus flavanone aglycones hesperetin and naringenin after single oral administration in human subjectsView study →}, with dose-proportional exposure across 150–900 mg ^{5Reference 5Rebello CJ et al. · 2020RCTSafety and pharmacokinetics of naringenin — a randomised, controlled, single-ascending-dose clinical trialView study →}.

Whatever is absorbed is rapidly glucuronidated and sulfated, so free aglycone is essentially undetectable in blood — the circulation carries naringenin glucuronides and sulfates, and urinary recovery is only a few percent of dose ^{11,12Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →Reference 12Kanaze FI et al. · 2007Clinical trialPharmacokinetics of the citrus flavanone aglycones hesperetin and naringenin after single oral administration in human subjectsView study →}. Naringenin also carries one stereocentre (C-2) that racemises readily in solution, so isolated material is typically near-racemic ^{20Reference 20Caccamese S et al. · 2007Racemisation at C-2 of naringin in sour oranges with increasing maturity determined by chiral HPLCView study →}. The upshot: oral bioavailability is poor and erratic, and — as with the other citrus flavanones — the in-vitro concentrations that drive its mechanisms are not what an oral dose delivers to tissue.

Clinical trials

Naringenin has one small pure-aglycone efficacy RCT (NAFLD) plus a clean safety/PK trial; everything else rests on naringin (conflicting) or citrus/hesperidin mixtures, and its anticancer/antiviral literature is entirely preclinical.

Pure naringenin	Naringin	Citrus / hesperidin	Anticancer / antiviral
1 efficacy (NAFLD) + 1 safety/PK	Conflicting lipid RCTs	Vascular RCTs (mixture)	Preclinical only

Last checked: July 2026.

Isolate vs. Plant Studies

Naringenin is over-credited in three familiar ways. The human evidence is mostly not naringenin: the cardiometabolic and vascular data come from grapefruit/orange juice, citrus extracts, or the glycoside naringin, all of which carry hesperidin, narirutin, vitamin C and fibre alongside — so effects can’t be pinned on the aglycone ^{3,6Reference 3Demonty I et al. · 2010The citrus flavonoids hesperidin and naringin do not affect serum cholesterol in moderately hypercholesterolaemic men and womenView study →Reference 6Rendeiro C et al. · 2016RCTFlavanone-rich citrus beverages counteract the transient decline in postprandial endothelial function in humans — a randomised, controlled, double-masked, crossover intervention studyView study →}. In plants it is a glycoside (or a chalcone): citrus stores it as bitter naringin, oranges as narirutin, and tomato skin as naringenin chalcone (the open-ring precursor) — a “naringenin-containing” food actually delivers one of these forms, absorbed differently ^{11Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →}. And the most-repeated fact about it is false — naringenin/naringin do not cause the grapefruit–CYP3A4 interaction (furanocoumarins do); their real clinical interaction is the opposite one, OATP inhibition that lowers absorption of drugs like fexofenadine ^{13,17Reference 13Paine MF et al. · 2006A furanocoumarin-free grapefruit juice establishes furanocoumarins as the mediators of the grapefruit-juice–felodipine interactionView study →Reference 17Bailey DG et al. · 2007Naringin is a major and selective clinical inhibitor of organic anion-transporting polypeptide 1A2 (OATP1A2) in grapefruit juiceView study →}. Within this database naringenin appears only at occurrence level (blue-lotus flower, black ant); note the hops “naringenin” is really 8-prenylnaringenin, a distinct prenylflavonoid with its own page, and yerba santa’s are methoxylated relatives — none belong here.

Prevalence in Nature

Naringenin is the signature flavanone of citrus (Rutaceae), but almost never present free in the intact plant — it is stored as glycosides and released only on hydrolysis ^{21Reference 21Kelebek H et al. · 2007Flavonoid composition of citrus juicesView study →}. Grapefruit is the headline, and it is a naringin story: whole white grapefruit carries ~14–17 mg naringin/100 g and grapefruit juice ~10–63 mg/100 mL (white > pink > ruby, plus large brand variation) — the naringin load responsible for grapefruit’s bitterness ^{22,23Reference 22Alam MA et al. · 2022Naringenin and its derivatives — health-promoting phytobiotic against resistant bacteria and fungi in humans (grapefruit naringin content)View study →Reference 23de Castro WV et al. · 2006Variation of flavonoids and furanocoumarins in grapefruit juices — a potential source of variability in grapefruit-juice–drug-interaction studiesView study →}. Other bitter citrus follow (bergamot juice ~17, sour orange ~2 mg naringin/100 mL), while sweet orange contributes mostly narirutin and only trace naringenin, and lemons/limes are minor ^{21,24Reference 21Kelebek H et al. · 2007Flavonoid composition of citrus juicesView study →Reference 24Gattuso G et al. · 2008Distribution of flavonoids and furanocoumarins in juices from Citrus bergamia (bergamot) and identification of new compoundsView study →}. The notable non-citrus source is tomato skin, where the form is different again — naringenin chalcone (chalconaringenin), which makes up 35–71% of tomato flavonoids and sits almost entirely in the peel; cooking partially cyclises it to naringenin, so tomato paste delivers meaningful bioavailable naringenin ^{25,26,27Reference 25Slimestad R et al. · 2008The flavonoids of tomatoesView study →Reference 26Bugianesi R et al. · 2002Naringenin from cooked tomato paste is bioavailable in menView study →Reference 27Burton-Freeman B et al. · 2020Bioavailability of naringenin chalcone in humans after ingestion of cherry tomatoesView study →}. There are essentially no non-plant sources.

Biosynthetically naringenin is the central branch point of the flavonoid pathway: chalcone synthase condenses p-coumaroyl-CoA with malonyl-CoA to naringenin chalcone, chalcone isomerase cyclises it to (2S)-naringenin, and from that single node flavone synthase gives apigenin, F3H+flavonol synthase give kaempferol (and onward to anthocyanins), and B-ring hydroxylation/methylation give the sister flavanones eriodictyol and hesperetin ^{28Reference 28Winkel-Shirley B · 2001Flavonoid biosynthesis — a colourful model for genetics, biochemistry, cell biology and biotechnology (the CHS→CHI→naringenin branch point)View study →}. Tomato peel is unusual in stalling at the chalcone (low chalcone-isomerase activity), which is why the chalcone dominates there.

Discovery & Synthesis

Naringenin is named after naringin, the bitter flavonoid glycoside of grapefruit from which it is released on hydrolysis; “naring-” traces back through scientific and botanical vocabulary to Sanskrit nāraṅga (“orange tree”) — the same root that gave Persian nārang, Spanish naranja and English orange. (The etymology is well documented linguistically; a specific coining author/date, and the frequently-repeated 1928 Asahina–Inubuse structure attribution, could not be confirmed against a primary indexed source — treat them as reported.) Structurally naringenin is 4′,5,7-trihydroxyflavanone, the parent, unsubstituted-B-ring flavanone: add a B-ring 3′-OH and you get eriodictyol; add a 3′-OH plus 4′-O-methyl and you get hesperetin — naringenin is those minus the extra B-ring substituents. It carries one stereocentre at C-2, but the C-2 proton is labile and the molecule racemises within hours in solution ^{20Reference 20Caccamese S et al. · 2007Racemisation at C-2 of naringin in sour oranges with increasing maturity determined by chiral HPLCView study →}.

Commercial naringenin is overwhelmingly extraction-derived: naringin is recovered from citrus processing waste — chiefly grapefruit peel and albedo — then hydrolysed to the aglycone, either by acid or, more selectively, by naringinase (an α-L-rhamnosidase + β-glucosidase complex used industrially to “debitter” grapefruit juice). Enzymatic/microbial-fermentation and total-synthesis routes exist but remain minor; citrus extraction plus hydrolysis dominates.

Patents: not yet researched (future patent-loop pass).

Toxicity & Safety

As a dietary flavanone consumed in citrus, naringenin has a low toxicity profile — the single-ascending-dose human trial found no clinically relevant adverse events or blood-marker changes from 150 up to 900 mg, well above dietary intake ^{5Reference 5Rebello CJ et al. · 2020RCTSafety and pharmacokinetics of naringenin — a randomised, controlled, single-ascending-dose clinical trialView study →}.

The grapefruit-interaction clarification is the load-bearing safety point — and it corrects a myth. The dangerous, clinically important grapefruit–drug interaction (sustained inhibition of intestinal CYP3A4 that raises the exposure of felodipine, simvastatin, many calcium-channel blockers and immunosuppressants) is caused by grapefruit FURANOCOUMARINS — bergamottin and 6′,7′-dihydroxybergamottin — not by naringin or naringenin ^{13,14Reference 13Paine MF et al. · 2006A furanocoumarin-free grapefruit juice establishes furanocoumarins as the mediators of the grapefruit-juice–felodipine interactionView study →Reference 14Paine MF et al. · 2005Two major grapefruit-juice components differ in time to onset of intestinal CYP3A4 inhibitionView study →}. Those furanocoumarins are mechanism-based (“suicide”) inhibitors that irreversibly inactivate enterocyte CYP3A4 for 24–72 h; the definitive experiment removed the furanocoumarins while keeping the flavonoids, and the resulting juice did not raise felodipine exposure ^{13Reference 13Paine MF et al. · 2006A furanocoumarin-free grapefruit juice establishes furanocoumarins as the mediators of the grapefruit-juice–felodipine interactionView study →}. Naringin was historically the first suspect (it is grapefruit’s signature bitter compound) ^{15Reference 15Bailey DG et al. · 1993Grapefruit juice–felodipine interaction — mechanism, predictability and effect of naringinView study →}, but naringenin is only a weak, reversible CYP3A4 inhibitor in vitro — far too weak to account for the prolonged clinical effect ^{16Reference 16Lu WJ et al. · 2011Enantiomers of naringenin as pleiotropic, stereoselective inhibitors of cytochrome P450 isoformsView study →}.

Where the flavanone does interact clinically is the opposite direction: inhibition of intestinal OATP uptake transporters (OATP1A2/2B1), which reduces absorption of certain drugs — grapefruit, orange and apple juices cut fexofenadine exposure to ~30–40% of control, and naringin is a major, selective OATP1A2 inhibitor in grapefruit juice ^{17,18Reference 17Bailey DG et al. · 2007Naringin is a major and selective clinical inhibitor of organic anion-transporting polypeptide 1A2 (OATP1A2) in grapefruit juiceView study →Reference 18Dresser GK et al. · 2002Fruit juices inhibit organic anion-transporting polypeptide-mediated drug uptake to decrease the oral availability of fexofenadineView study →}. So the sensible advice is to separate OATP-substrate drugs (fexofenadine, some β-blockers, aliskiren, certain antibiotics) from large citrus-juice loads. Naringenin also has weak, context-dependent estrogen-receptor activity (antiestrogenic in some assays, weakly estrogenic in others), a reason for caution with concentrated supplements in hormone-sensitive conditions ^{19Reference 19Galluzzo P et al. · 2008The nutritional flavanone naringenin triggers antiestrogenic effects by regulating estrogen-receptor-alpha palmitoylationView study →}.

Dosage

There is no established dose of naringenin. The one efficacy trial used 200 mg/day of the pure aglycone for NAFLD ^{1Reference 1Namkhah Z et al. · 2021RCTDoes naringenin supplementation improve lipid profile, severity of hepatic steatosis and probability of liver fibrosis in overweight/obese patients with NAFLD? A randomised, double-blind, placebo-controlled clinical trialView study →}; a safety trial tested single doses up to 900 mg without adverse effect ^{5Reference 5Rebello CJ et al. · 2020RCTSafety and pharmacokinetics of naringenin — a randomised, controlled, single-ascending-dose clinical trialView study →}; and the conflicting lipid trials used naringin at ~450 mg/day ^{2Reference 2Barajas-Vega JL et al. · 2022Clinical trialNaringin reduces body weight, plasma lipids and increases adiponectin levels in patients with dyslipidaemiaView study →}. Because naringin is a poorly-absorbed prodrug, the delivered naringenin exposure depends heavily on form and on the individual’s gut microbiome ^{11Reference 11Erlund I et al. · 2001Plasma kinetics and urinary excretion of the flavanones naringenin and hesperetin in humans after ingestion of orange juice and grapefruit juiceView study →}.

These are research figures, not a recommendation — the pure-aglycone evidence is a single small trial, the naringin lipid data conflict, and the vascular evidence belongs to citrus mixtures, not naringenin.

References