Curry Leaf

What is Curry Leaf?

Curry leaf is the leaf of Murraya koenigii, a tree in the citrus family (Rutaceae) that the USDA regulates as a host of the insect that spreads citrus greening. Kew's Plants of the World Online now files it as Bergera koenigii L., the name Linnaeus published in Mantissa Plantarum in 1767, with Murraya koenigii (L.) Spreng. among eight synonyms; APHIS Federal Order DA-2022-07 prints both names side by side.

Kew gives a native range from Pakistan and Sri Lanka to Vietnam and southern China, with introduced populations on Java, Sumatra and Fiji among other places. Cooks strip the leaflets from the stalk and fry them in oil or ghee at the start of a dish. One US seller of the dried leaf tells buyers it "is removed before serving and not eaten whole." That matters: the cook extracts the leaf into fat and discards it, while a capsule user swallows dried leaf tissue.

Three things share the word "curry." Curry leaf is this Rutaceae tree. The garden-center "curry plant" is Helichrysum italicum, a silver-leaved Mediterranean member of the daisy family (Asteraceae), named for its smell. Curry powder is a spice blend, and only its own ingredient list can say whether it contains any curry leaf. The common name "sweet neem" also misleads: neem is Azadirachta indica, in a different family, the Meliaceae.

Common Names

• Curry leaf, curry tree, curry bush, sweet neem

• Kadi patta, kari patta (Hindi); one US brand prints "Kari Neem Patha"

• Karuveppilai (Tamil); karapincha (Sinhala), the root of "karapinchamines," two alkaloids a Kyoto group named in 2013

• Krishnanimba (Ayurvedic, per Balakrishnan and colleagues' 2020 review in Antioxidants)

• Bergera koenigii, Murraya koenigii, Chalcas koenigii (botanical names and synonyms)

Primary Active Compounds

• Carbazole alkaloids. Joshi and colleagues at CSIR-Central Drug Research Institute (Natural Product Communications 2015) measured mahanimbine at 0.13 to 0.42 percent, koenimbine at 0.04 to 0.69 percent and koenimbidine at 0.06 to 0.20 percent by weight in dried leaf from seven Uttar Pradesh samples, a more than tenfold koenimbine spread within one state.

• Mahanine, girinimbine, koenidine, murrayanine and murrayanol. Ramsewak and colleagues (Journal of Agricultural and Food Chemistry 1999) isolated mahanimbine, murrayanol and mahanine from fresh leaves.

• Essential oil: 0.14 to 0.80 percent of shade-dried leaf across 58 wild Himalayan populations, led by alpha-pinene (4.5 to 71.5 percent) in some and sabinene (up to 66.1 percent) in others (Verma and colleagues, Chemistry and Biodiversity 2013).

• Carotenoids: lutein 8.2 to 99.5 mg and beta-carotene 2.9 to 19.2 mg per 100 g of dried leaf, depending on drying method (Shivanna and Subban, International Journal of Food Sciences and Nutrition 2012).

• Flavonoids: catechin 0.482, myricetin 0.517 and quercetin 0.394 mg per gram of dry leaf under optimized extraction (Ghasemzadeh and colleagues, 2014).

Key Note

Fresh curry leaf in the United States is a quarantine commodity. Since APHIS's January 2008 citrus greening order, leaves for consumption leaving psyllid-quarantined areas have had to be fumigated with methyl bromide or, from areas free of citrus greening, irradiated; a later compliance-agreement protocol, now Federal Order DA-2022-07, added a processing route (see Special Considerations).

Curry leaf is a fragrant cooking leaf with a measurable nutrient load, a large chemistry, a thin human record on blood sugar and no human hair study the author could find, and nearly everything a buyer cares about changes between the tree and the jar.

Primary Functions & Benefits

Curry leaf's established function is flavor. The glucose material below, which this issue owns, is the only part tested in people with a metabolic endpoint.

Blood glucose, the human record

Five human studies with a glucose endpoint are locatable, and no two used the same preparation.

• Iyer and Mani (Plant Foods for Human Nutrition 1990): 12 g of dried leaf powder daily, supplying 2.5 g of fiber, for one month in 30 adults with non-insulin-dependent diabetes. Fasting and 2-hour post-meal glucose fell transiently at day 15. Glycosylated serum proteins, glycosylated LDL, serum lipids, uronic acid and amino acids did not change at day 15 or day 30. The abstract describes no control group.

• Senadheera and Ekanayake (International Journal of Food Sciences and Nutrition 2012): Sri Lankan porridges of leaf water extract, rice and coconut milk. The curry leaf porridge had a glycemic index of 44 plus or minus 8; plain coconut milk porridge scored 31 plus or minus 5. Low-GI, but not lower than the porridge without the leaf.

• Farooq and colleagues (Pakistan Journal of Pharmaceutical Sciences 2023): encapsulated aqueous extract at 5 or 10 mg per kg in 45 women with type 2 diabetes, glucose and HbA1c measured at day 0 and day 45. Both treatment groups showed significant reductions (p below 0.05). The abstract gives no values, no control arm description and no blinding.

• Suganthi and colleagues (Cardiometry 2022): a quasi-experimental study of curry leaf powder with 60 participants who had type 2 diabetes and mildly raised lipids; the abstract does not say how many received the powder. Fasting glucose fell 5.72 percent and post-meal glucose 6.39 percent in the experimental group. The abstract states neither dose nor duration.

• Joseph (Nursing Journal of India 2015): a Mangalore community study, indexed without an abstract.

None is a double-blind, placebo-controlled trial of a defined product with HbA1c as the primary outcome, published in full.

Antioxidant activity, measured in food

Gupta and Prakash (Plant Foods for Human Nutrition 2009) found curry leaf highest of four Indian leafy greens in total antioxidant activity, 2,691.78 micromoles ascorbic acid equivalent per gram. Devatkal and colleagues (Journal of Food Science and Technology, 2011 online) added 2 percent aqueous curry leaf extract to raw chicken patties and cut the lipid oxidation marker TBARS by an average 25.5 percent over eight refrigerated days, against 18 percent for the synthetic antioxidant BHT. That is food preservation, not oxidation inside a person.

Forms & Standardization

No curry leaf product the author found is standardized to a carbazole alkaloid, an oil content or a carotenoid. The one marker two products standardize to is iron, which is the strangest fact in this section.

Fresh leaf

The form every cuisine that uses curry leaf actually cooks with.

Dried whole leaf

Rani Brand "Dried Curry Whole Leaves (Kari Neem Patha)" is 14 g for $8.99, "AIR DRIED: in Houston, TX," "NON-IRRADIATED," and "grown organically without the use of pesticides," with no organic certification stated. Pure Indian Foods sells 1 oz of USDA certified organic dried leaves, origin USA, for $11.99, best by June 30, 2029. Neither gives a drying temperature, moisture or any compositional figure. At Rani's size, the 12 g daily dose of the 1990 study is 86 percent of a bag a day.

What drying does, by the numbers

• Carotenoids. Shivanna and Subban at CFTRI Mysore (2012) dried leaves eight ways. Microwave drying kept the most lutein (99.4 mg per 100 g) and beta-carotene (19.2 mg); cross-flow drying the least lutein (8.2 mg); infrared drying the least beta-carotene (2.9 mg). A 6.6-fold spread set by the dryer alone.

• Alkaloids and flavor. Negi and colleagues (Food Chemistry 2024) found short, hot (80 degree C) drying retained more phenolics, flavonoids and alkaloids, while 40 degree C conductive hydro drying gave the best color, antioxidant activity and GC-MS flavor retention. No setting preserved everything.

Powder in capsules

HerbEra Curry Leaf Capsules (Walmart, 60 capsules labeled 500 mg, $17.59) list "Organic Curry Leaf (Murraya koenigii) Dried Leaf." The directions say "take two capsules twice a day with food" and "For best results, take for 30 days," while another field on the same listing says "Take 2 capsules daily," and the listing claims a "Unique Extraction Method" for a product whose ingredient is dried leaf. Four capsules supply 2 g, one-sixth of the 1990 study's dose.

"Extract" tablets and water extracts

Merlion Naturals "Curry Leaves Extract Tablets 500mg" lists only "Curry Leaves (Murraya koenigii)," with no ratio, solvent or marker. Farooq's 2023 trial used a water extract at 5 or 10 mg per kg, 350 or 700 mg a day for a 70 kg woman, with no stated ratio to leaf. Its abstract puts the extract's total alkaloids at 2.01 mg per 100 g. That assay differs from Joshi's UPLC measurement of 130 to 420 mg of mahanimbine alone per 100 g of dried leaf, so the figures are not directly comparable, but a gap of two orders of magnitude fits what water does to a fat-soluble alkaloid.

Iron-standardized "curry leaf" extracts

Orgen-I, made by Orgenetics, Inc. of Brea, California, is described in a 2025 Cureus trial as curry leaf extract "standardized to 3.6% elemental iron," 18 mg per 500 mg capsule, produced by "a low-heat, water-based method." The same paper puts dehydrated curry leaf at "approximately 12 mg of elemental iron per 100 g," or 0.012 percent. That makes the extract 300 times the leaf's concentration; 18 mg is the iron in 150 g of dehydrated leaf by the paper's own figure. bios Naturprodukte in Europe listed a capsule in which "500 mg of curry leaf extract provides 15 mg of iron," about 250 times the leaf's concentration. Neither discloses an extract ratio or explains how water extraction gets there. Judge either as an iron supplement.

Research fractions and topical forms

A mahanine-enriched fraction (Satyavarapu 2020) and an alkaloid-enriched fraction (Thakur 2024) exist only in animal research. Topically, the traditional hair oil boils fresh leaves in coconut oil "until they are reduced to a black residue" (Balakrishnan 2020), and Gattefossé, a French ingredient maker, tested a 1 percent leafy-stem extract on facial skin (Lorion 2023). Neither has a hair outcome.

Food Sources

Curry leaf is the food. The question is how much of it a person eats and what survives the kitchen.

Composition per 100 g of fresh leaf

The Indian reference values, reproduced in a 2020 ICAR Indian Horticulture article (Raghu and colleagues) from a 2011 Indian Journal of Natural Products and Resources table, give protein 6 g, fat 1 g, carbohydrate 8.7 g, calcium 830 mg, iron 0.93 mg and beta-carotene 7,560 micrograms. Balakrishnan's 2020 review puts moisture at 63.2 percent.

What 10 g of fresh leaf delivers

About 83 mg of calcium (8 percent of the 1,000 mg adult RDA), 0.09 mg of iron (about 1 percent of the 8 mg men's RDA) and 756 micrograms of beta-carotene. At the Institute of Medicine's 12 to 1 conversion, that is about 63 micrograms RAE, 7 percent of the 900 microgram RDA for men and 9 percent of the 700 microgram RDA for women.

The calcium is partly spoken for

Radek and Savage (International Journal of Food Sciences and Nutrition 2008) found curry among seven of 11 Indian leafy vegetables whose oxalate was entirely insoluble, ranging across that group from 209.0 to 2,774.9 mg per 100 g of dry matter, with 3.3 to 86.7 percent of each vegetable's calcium bound in the insoluble fraction. The abstract does not give curry's own figure. The 830 mg is a ceiling, not an absorbed dose.

Fresh versus dried, by the reference tables

The same ICAR table lists dehydrated leaves at calcium 2,040 mg, iron 12 mg and beta-carotene 5,292 micrograms per 100 g. Removing about 63 percent water should concentrate everything roughly 2.6-fold. Calcium rose about 2.5-fold, as expected. Beta-carotene fell, which on that basis implies roughly 70 percent was lost in drying. Iron rose about 13-fold, more than water loss explains, which points to a different sample or contamination. In the same table protein only doubled (6 to 12 g) while carbohydrate rose 7.4-fold (8.7 to 64.31 g), so the two columns probably do not come from one lot, and the 70 percent figure is an inference, though it sits inside Shivanna's carotenoid spread.

Cooking

Devadas Rajammal and colleagues (Biomedical and Environmental Sciences 1996) listed curry leaves among four carotene-rich greens available year-round in Coimbatore and, across the greens they cooked, found carotene losses greatest with boiling and smallest with shallow frying. Frying the leaf in oil is the gentlest common method, and it moves fat-soluble carotenoids into the fat that carries them into the meal.

Is dietary intake enough?

For calcium and provitamin A, curry leaf is a useful contributor in a cuisine that uses it daily and a trivial one at 2 g of dried leaf in a capsule. For blood sugar, the only tested powder dose equals roughly 30 g of fresh leaf a day and did not hold for a month. Eat the leaf; the capsule does nothing the leaf does better.

Who Should Take Curry Leaf

As a food, anyone who likes it. As a capsule or extract, no population has a demonstrated benefit.

Cooks

Fried in oil at the start of a dal, sambar or thoran, a handful of leaves seasons the dish and adds some calcium and provitamin A. No evidence suggests a capsule improves on that.

Adults with type 2 diabetes, as food

Every human glucose treatment study of curry leaf enrolled people with diabetes, and none shows a durable effect from a defined product. Cooking with the leaf is consistent with the evidence; reducing a prescribed drug on the strength of it is not. Cinnamon, gymnema, bitter melon and fenugreek have their own issues in this archive, and none of their trial records transfers to this leaf.

Who gains nothing

Anyone buying capsules or oils to grow hair or reverse graying, and anyone buying an "iron from curry leaf" capsule thinking it is a gentle herb rather than an iron supplement.

Who Should AVOID or Use Caution

Contraindications

• Hereditary hemochromatosis, other iron overload, or a clinician's instruction not to take iron: avoid iron-standardized curry leaf extracts, which supply 15 to 18 mg of elemental iron per capsule.

• Pregnancy and breastfeeding, for capsules and extracts. The author found no reproductive toxicity study of the leaf, its extracts or its carbazoles. Culinary use is a different exposure.

• Children, for any capsule. No pediatric data exist, and the iron-standardized products carry an iron poisoning risk.

• Anyone who has reacted to curry leaf in food. The author found no published case of curry leaf allergy in PubMed, which means no characterized pattern, not no risk.

Use Caution

• Insulin and the sulfonylureas glipizide, glimepiride and glyburide, which cause hypoglycemia on their own. Curry leaf's proposed effects add to theirs. No study has measured the combination.

• Calcium oxalate kidney stones. Curry's oxalate was entirely insoluble in Radek and Savage's 2008 analysis, but its own figure is not in the abstract, so the size of the concern is unknown rather than known to be small.

• Liver disease. A methanol leaf extract raised ALT and caused liver inflammation in rats at an acute 500 mg per kg dose (Adebajo and colleagues, Phytomedicine 2006). It is the only liver injury signal the author found, it came from an extract, and the same paper reported lower liver enzymes after 14 days of repeated dosing.

• Gardeners and travelers in citrus regions. Moving fresh leaves or plants out of a psyllid or citrus greening quarantine area can break federal and state rules (see Special Considerations).

Critical Safety Point

Some products sold as curry leaf extract are, by their makers' own figures, concentrated iron at 15 to 18 mg per capsule, 250 to 300 times the iron in the same weight of dehydrated leaf. US rules (21 CFR 101.17(e)) require iron-containing supplements in solid oral form to warn that "accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6." A capsule presented as a leaf powder can sit in a cupboard without that warning ever being read. Store it as the iron supplement it is.

Recommended Dosages

There is no established dose of curry leaf for any health purpose, and no regulator, pharmacopeia or clinical body the author could find sets one. The amounts used in human trials belong to those trials and appear in Special Considerations, scoped to their settings. Nothing below is a target.

Fresh and dried leaf

A culinary ingredient used to taste. No study has tested a fresh-leaf regimen against a health outcome, and no dose of dried leaf has produced a lasting effect on any measured outcome in a human.

Capsules of dried leaf

The HerbEra label directs "two capsules twice a day with food," about 2 g of dried leaf, and elsewhere "2 capsules daily." That figure comes from a label, not a study.

Extracts

No retail extract reviewed discloses the ratio needed to convert its milligrams into grams of leaf, so a milligram figure on the bottle cannot be compared with anything.

Iron-standardized extracts

These are iron doses. The bios label directed one 15 mg capsule daily for three months. The Institute of Medicine's adult Tolerable Upper Intake Level for iron is 45 mg a day from all sources, and a multivitamin with 18 mg plus ordinary dietary iron plus one of these capsules can approach it.

Duration

The longest monitored oral exposure to a curry leaf-only preparation is 60 days, and that was the iron-standardized Orgen-I extract. For glucose it is 45 days (Farooq 2023, water extract), and for dried leaf powder one month (Iyer and Mani 1990). Past one month, a dried-leaf capsule user is beyond the monitored record.

Timing & Administration

Nothing in the human record tests timing directly.

With food and fat

Cooks fry the leaf in oil or ghee first, and Pure Indian Foods' label says the dried leaf releases flavor when toasted in ghee. The carotenoids and carbazoles are fat-soluble, so the fat carries what dissolves into the meal. A dry capsule with water does none of this.

Relative to meals

Iyer and Mani measured fasting glucose and glucose 2 hours after a meal. The proposed mechanism most directly tied to eating, inhibition of pancreatic amylase, would act at the meal if it acts at all. HerbEra's "with food" direction fits that, though it was not derived from it. The Cureus iron trial gave its capsule once daily after a meal with 240 mL of water; iron timing matters for drug interactions, covered below.

Timeline of Effects

What was measured, and when

Iyer and Mani measured at days 1, 15 and 30. The glucose reduction appeared at day 15 and was transient, and glycated serum proteins, which reflect roughly the preceding two to three weeks of glucose, did not move. Farooq measured at day 0 and day 45; HbA1c tracks glucose over the roughly 120-day life of a red cell, so 45 days captures only part of any real change. Senadheera and Ekanayake measured one 2-hour post-meal curve, a glycemic index test rather than a treatment trial. Suganthi's abstract gives no duration.

Onset and peak

No study has compared a meal with curry leaf against the identical meal without it. The closest comparison found the leaf porridge's GI (44) above plain coconut milk porridge (31).

A fair trial, and when to stop

No study defines one. The only durability data point is an effect present at day 15 and gone by day 30. Anyone with diabetes who believes curry leaf is helping should judge it by the meter readings and HbA1c their clinician already tracks, and should not change a prescribed dose on that basis.

Benefits of Taking Curry Leaf

Documented in humans, for curry leaf alone

The five glucose studies in Primary Functions, none of them both controlled and durable, and one topical cosmetic result: Lorion and colleagues (Journal of Cosmetic Dermatology 2023) applied a 1 percent leafy-stem extract to the faces of female volunteers twice daily for 98 days and reported visibly reduced nasolabial fold and jowl severity. The manufacturer ran it, on skin, with a proprietary extract.

Documented in humans, for formulas

• Prostate. Sengupta and colleagues (Clinical Therapeutics 2011) randomized 46 men over 50 to a capsule of standardized Murraya koenigii and Tribulus terrestris leaf extracts, two capsules twice daily, or tamsulosin 400 micrograms for 12 weeks. Median symptom scores fell from 17.0 to 9.0 and from 14.0 to 8.0, with no significant difference between groups; 19 of 23 finished the herbal arm.

• Irritable bowel syndrome. Lauche and colleagues (Complementary Therapies in Medicine 2016) found a curry leaf, pomegranate and turmeric decoction no better than placebo in 32 patients over a four-week crossover (p = 0.26), with 11 dropouts.

• Anemia. The 2025 Orgen-I trial is evidence about 18 mg of iron a day.

Documented in animals

• Water extract. Kesari and colleagues (Journal of Ethnopharmacology 2007) gave 300 mg per kg of aqueous leaf extract to streptozotocin-diabetic rats for 30 days: fasting glucose fell 48.2 percent and triglycerides 37.1 percent.

• Whole leaf powder. Three AIIMS New Delhi studies fed the dried leaf itself in the diet, with weak results. At 5, 10 and 15 percent of the diet for five weeks it lowered blood glucose by up to 21.4 percent in mildly (alloxan) diabetic rats but not significantly in moderately (streptozotocin) diabetic ones (Yadav and colleagues 2002). In fructose-fed rats 15 percent leaf "failed to exert any effect" on glucose, insulin or cholesterol over 30 days, while 10 percent mustard seed in the same study did lower them (Yadav and colleagues 2004); in streptozotocin-diabetic animals over 60 days its results "were not statistically different" from diabetic controls (Grover and colleagues 2003). Extracts worked more consistently in rodents than the leaf eaten whole, at doses no human would match.

• Isolated alkaloids. Mahanimbine at 2 and 4 mg per kg for 12 weeks held high-fat-diet weight gain in male mice to 51.70 and 47.37 percent against 71.02 percent in controls and improved glucose clearance (Jagtap and colleagues, BioFactors 2017). Koenidine lowered post-meal glucose in db/db mice (Patel and colleagues, Journal of Natural Products 2016).

Documented in cells

Pancreatic amylase inhibition, muscle-cell glucose uptake, cytotoxicity of murrayazoline and O-methylmurrayamine A to DLD-1 colon cancer cells at IC50 5.7 and 17.9 micromolar (Arun and colleagues 2017), and melanin suppression by the leaf's principal alkaloids (Nakamura 2013). All at concentrations no human blood level has been shown to reach.

Marketed, undocumented

• Hair growth and graying. A PubMed search on October 19, 2026 combining curry leaf or Murraya koenigii with hair, alopecia, graying or melanogenesis returned five records. None tested hair growth or hair color in a person or animal, and the one that measured melanin found the leaf's alkaloids suppress it.

• Cholesterol. HerbEra lists "Cholesterol Support." The 1990 human study measured cholesterol, lipoproteins and triglycerides at 15 and 30 days and found no appreciable change.

• Weight loss. The alkaloid results are in high-fat-fed mice; no human weight trial of curry leaf alone is in PubMed.

Potential Negatives & Side Effects

What people actually reported

The studies are small and report harms thinly. In the IBS crossover, one third of patients registered at least one minor adverse event "that might be related" to the three-herb decoction. In the prostate trial, mild joint pain was the most common adverse event in both the herbal and tamsulosin arms. The Orgen-I trial reported none among 86 completers. The 1990 and 2023 glucose abstracts do not mention adverse events, which is an absence of reporting, not a finding of safety.

Hypoglycemia, by inference

With insulin or a sulfonylurea, an added glucose-lowering preparation can push glucose too low. No case has been published and no study has tested the combination, so this is a reasoned caution, not an observed event.

Allergy

No published case of curry leaf allergy, contact dermatitis or anaphylaxis was found in PubMed, and no cross-reactivity study with citrus exists. Mouth tingling, rash or swelling after eating the leaf should be treated as a reaction to it until shown otherwise.

Deficiency Symptoms

What curry leaf addresses

No deficiency state exists for curry leaf or for any compound specific to it; carbazole alkaloids have no known role in human physiology. What the leaf can address, as food, is dietary shortfall in beta-carotene and calcium. Devadas Rajammal and colleagues (1996) built a seasonal calendar of cheap carotene-rich foods for vitamin A programs in Coimbatore, against a stated daily requirement of 2,400 micrograms of beta-carotene, and listed curry leaves as a year-round and winter source. That is the leaf's most defensible public health role.

Bottom line

Night blindness, dry eyes or brittle bones have a diagnosis, a blood test and an established treatment. Curry leaf in the diet can help prevent the first two. A capsule at 2 g of dried leaf supplies about 106 micrograms of beta-carotene, under 1 percent of a man's vitamin A RDA, and treats nothing.

Toxicity Symptoms

At high intake

No human overdose of curry leaf turned up in the author's searches. The animal record is uneven:

• A methanol extract of leaves from Nigerian-grown trees was "moderately toxic" to rats, LD50 316.23 mg per kg, and an acute 500 mg per kg dose raised ALT and inflamed the liver (Adebajo 2006). The abstract does not state the route.

• A mahanine-enriched fraction caused no toxicity in mice at a single 5,000 mg per kg dose or at 300 mg per kg daily for up to 180 days (Satyavarapu 2020).

• An alkaloid-enriched fraction at up to 1 g per kg daily for 28 days caused no tissue damage in rats (Thakur 2024).

Extracts of the same leaf made with different solvents in different labs disagree by more than an order of magnitude. The methanol extract's LD50 should govern caution until it is explained.

Pesticide residues, the realistic toxicity

Nair and colleagues (Entomon 2013) bought curry leaves monthly in Thiruvananthapuram district, Kerala, from January to June 2012 and found 12 pesticides, including chlorpyrifos, quinalphos, triazophos, methyl parathion, cypermethrin, alpha-endosulfan and ethion. Profenofos, which the authors noted was "not registered for use in curry leaf" and banned for sale and use in Kerala, reached 25.63 mg per kg in one sample. The authors rated it a high chronic risk at 85.43 percent of an acceptable daily intake. That percentage depends on which ADI is used: their intake estimate of 0.000854 mg per kg of body weight a day is about 3 percent of the 0.03 mg per kg ADI set by the FAO/WHO Joint Meeting on Pesticide Residues, so read the 85 percent figure as the authors' rating rather than a settled risk number. Profenofos is an organophosphate the World Health Organization classes as moderately hazardous (Class II).

Signs to reduce or stop

• Shakiness, sweating, confusion or a low meter reading in anyone on insulin or a sulfonylurea

• Dark urine, pale stools, yellowing skin or eyes, or right upper abdominal pain

• Mouth or skin reaction after eating the leaf

• Nausea, vomiting or black stools after a child swallows an iron-standardized capsule, which is a poison-control call

General note

For a leaf eaten across South Asia every day, the measured risks come from what was sprayed on it, what grew on it and what was added to it, not from the leaf's own chemistry.

How Curry Leaf Works

Curry leaf's glucose and pigment actions both run through its carbazole alkaloids, and neither has been shown to occur in a human body at a dose anyone eats.

The carbazole chemistry

A carbazole is a three-ring nitrogen compound, two benzene rings fused either side of a five-membered pyrrole ring. Murraya koenigii makes many, mostly pyranocarbazoles, which add an oxygen-containing pyran ring carrying a prenyl or geranyl side chain. Mahanimbine, girinimbine and koenimbine are pyranocarbazoles; murrayanine, reported by Chakraborty and colleagues in 1965, is a simpler carbazole aldehyde. Nakamura's Kyoto group isolated 14 carbazoles from one Sri Lankan leaf extract in 2013, two of them new. They are lipophilic, which is why published isolations use acetone, methanol and ethyl acetate rather than water, and why frying the leaf in fat is, chemically, a better extraction than steeping it.

Glucose mechanism 1: slower starch digestion

Ponnusamy and colleagues (Evidence-Based Complementary and Alternative Medicine 2011) screened 91 extracts of 11 Ayurvedic plants against human pancreatic amylase. An isopropanol curry leaf extract inhibited it at an IC50 of 127 micrograms per mL, but in a concentration-independent pattern, so more extract did not reliably mean more inhibition. Slower starch breakdown would blunt the post-meal glucose rise, acting in the gut without the alkaloids needing to be absorbed.

Glucose mechanism 2: more glucose into muscle

Mahanine increased glucose uptake in L6 rat muscle cells and fat cells through Akt activation and translocation of the GLUT4 transporter to the cell surface; blocking Akt with wortmannin reversed it (Nooron and colleagues, Biochemical and Biophysical Research Communications 2017). Koenidine did the same in L6-GLUT4myc myotubes and was 2.7 times more bioavailable than a related carbazole, which the authors credited for its stronger effect in diabetic animals (Patel 2016).

Glucose mechanism 3: less dietary fat absorbed

In high-fat-fed mice, mahanimbine increased fat excretion, reduced fat in liver and adipose tissue and upregulated insulin-responsive genes (Jagtap 2017). Part of the glucose improvement there may follow from less weight gain rather than a direct glucose effect.

What the doses mean, for scale only

In rodents, a 0.1 g per kg oral dose produced peak plasma levels of 1.81 micromolar koenimbine at about 50 minutes and 2.82 micromolar koenidine at 240 minutes, per Balakrishnan's 2020 review. With mahanimbine at 0.13 to 0.42 percent of dried leaf (Joshi 2015), 12 g of powder holds roughly 16 to 50 mg of it and 2 g roughly 3 to 8 mg. Scaled by body surface area with the factor of 12.3 in FDA's 2005 starting-dose guidance, the 2 to 4 mg per kg mouse doses that slowed weight gain correspond to about 11 to 23 mg for a 70 kg adult. The 1990 study's 12 g could plausibly have reached that range; a 2 g capsule regimen falls below it. This is a plausibility check, not a dose, and no human has had mahanimbine measured in blood after eating curry leaf.

The hair mechanism, which runs the wrong way

Gray hair is hair whose follicle melanocytes have stopped depositing melanin; an anti-graying agent would need to increase melanin production. Nakamura and colleagues (Bioorganic and Medicinal Chemistry 2013) found that a methanol extract of Sri Lankan curry leaves, its ethyl acetate fraction and its principal carbazole alkaloids inhibited melanin production in theophylline-stimulated B16 melanoma 4A5 cells, and analyzed which structures drive that inhibition. Koenimbine has also been reported to inhibit melanogenesis. The leaf's best-characterized pigment chemistry is a skin-lightening lead, the opposite of an anti-graying one. The nearest hair growth finding is incidental: in Nagappan and colleagues' 2012 rat study of topical extract and carbazoles on 8 mm skin wounds, healed tissue showed "hair follicle buds." A healing wound regrowing its own follicles is not scalp hair growth.

The volatile oil

Its terpenes make the aroma and, in vitro, kill insects (LC50 1.93 mg per mL against diamondback moth larvae, Reddy and colleagues 2015). The oil has no credited systemic action in humans; it is what the cook is buying.

Synergistic Supplements

No combination with curry leaf alone has been tested in humans for synergy. What the record shows:

• Cooking fat. The one pairing with a chemical rationale: the carotenoids and carbazoles are fat-soluble, and oil is the original delivery system.

• Vitamin C with iron-standardized extracts. The 2025 Cureus trial tested exactly this. Hemoglobin rose 12.96 percent on Orgen-I alone and 8.40 percent on Orgen-I plus 90 mg of vitamin C from amla. Adding vitamin C did not improve the result.

• Mustard seed. In Yadav's 2004 rat study, 10 percent mustard seed lowered glucose, insulin and cholesterol where 15 percent curry leaf did nothing. A comparison, not a synergy.

• Tribulus. Paired with curry leaf in the prostate formula; the result cannot be split between the two.

• Other glucose botanicals. No study has combined cinnamon, gymnema, bitter melon or fenugreek with curry leaf, and stacking unquantified glucose-lowering botanicals on a prescription is a way to find hypoglycemia, not synergy.

Interactions & What NOT to Take

Glucose-lowering drugs

Insulin, the sulfonylureas glipizide, glimepiride and glyburide, the meglitinides repaglinide and nateglinide, and to a lesser degree metformin and the SGLT2 and DPP-4 inhibitors. No interaction study with curry leaf exists in PubMed. The concern is additive glucose lowering, largest with drugs that can cause hypoglycemia alone. Anyone adding a curry leaf capsule or extract to one should tell the prescriber and check glucose more often for the first weeks.

Drugs that iron blocks, for iron-standardized extracts only

A 15 to 18 mg iron dose reduces absorption of levothyroxine, doxycycline and minocycline, ciprofloxacin and levofloxacin, levodopa and the HIV drug dolutegravir. Each drug's label sets the spacing. A buyer who does not know a "curry leaf" capsule is an iron product will not know to space it.

Drug metabolism

The author found no study of curry leaf, its extracts or its carbazoles against human cytochrome P450 enzymes or drug transporters. That is an absence of data, not evidence of no effect.

What not to take it with

A glucose-lowering prescription without the prescriber's knowledge; the iron-blocked drugs above if the product is iron-standardized; a second iron supplement; and any product that does not name the species, the plant part and, for an extract, the ratio.

Quality, Testing & Adulteration

Pesticides are the documented problem

Commission Implementing Regulation (EU) 2023/174 of January 26, 2023 lists "curry leaves (Bergera/Murraya koenigii)" from India in Annex II of Regulation 2019/1793 for pesticide residues, with identity and physical checks on 50 percent of consignments. Scotland's 2024 amendment (SSI 2024/12) applies the same 50 percent frequency and names acephate. A June 2014 Down To Earth report on EU Rapid Alert System figures counted 12 curry leaf notifications among 111 pesticide notifications on Indian produce, naming profenofos. The ICAR-National Research Centre for Grapes in Pune published a method in 2023 screening curry leaf for 490 pesticides, most at a quantification limit of 0.01 mg per kg (Jankar and colleagues, Journal of Environmental Science and Health Part B). The testing exists; a label silent on it has not used it.

What washing removes

Paramasivam at Tamil Nadu Agricultural University found household washing removed 2 to 65 percent of 10 organophosphate residues from curry leaves (Food Chemistry 2020). For pyrethroids and hexaconazole, a 2 percent lemon juice soak removed 35.71 to 56.52 percent, hot water 18.44 to 46.74 percent and tap water 3.57 to 27.84 percent (Journal of Food Science and Technology 2022). Washing helps; it does not clean a heavily sprayed leaf, and nobody washes a capsule.

Salmonella on fresh leaves

After the Street Spice festival in Newcastle upon Tyne in February and March 2013, 592 people reported gastrointestinal illness. Indistinguishable Salmonella Agona isolates came from patients and from fresh curry leaves in a coconut chutney, with enteroaggregative E. coli and Shigella also implicated, and investigators found unclear instructions on using fresh, uncooked leaves in finished dishes (Waldram and colleagues, Epidemiology and Infection 2018). In a Public Health England survey of 774 fresh herb samples in early 2014, five of the nine Salmonella-positive samples were curry leaves (Willis and colleagues 2015). In 2017, 26 percent of 118 imported curry leaf samples tested in England carried Salmonella, the highest rate of any herb in that program (McLauchlin and colleagues 2018). Washing is not a kill step; cooking is.

The iron extracts and their trial

The 2025 Cureus trial of Orgen-I (Patel and colleagues) randomized 96 adults with iron deficiency anemia, analyzed the 86 who finished, and lists an Orgenetics employee among its three authors. Its abstract says both active capsules improved hemoglobin "compared to placebo (p<0.001), with greater efficacy in the combination group." Its own results give the larger hemoglobin rise to the iron-only capsule (12.96 percent versus 8.40 percent), its comparison table gives p above 0.05 for placebo against the combination capsule at day 60, and placebo hemoglobin rose 6.80 percent. The abstract also states the entry hemoglobin as "8-11 mg/dL" where the methods say g/dL. None of this explains how a water extract of a 0.012 percent iron leaf reaches 3.6 percent.

Nutrient numbers that do not agree

Balakrishnan's 2020 review prints curry leaf calcium as 19.73 mg per 100 g; the Indian reference table gives 830 mg, a 42-fold disagreement. Published beta-carotene runs from 0.85 mg per 100 g in an HPLC survey of South Indian spices (Ashokkumar and colleagues 2019) to 7.56 mg in the reference tables to 19.2 mg in microwave-dried leaf. A label saying "rich in calcium" or "rich in vitamin A" is choosing among these.

Identity and third-party testing

Fresh curry leaf is hard to fake in the hand; powder is easy. The author found no USP-NF or other pharmacopeial monograph with identity tests or marker limits for curry leaf, and no ConsumerLab review. A 2013 study in Molecular Biotechnology separated 92 wild and cultivated accessions by three DNA fingerprinting methods, so identity testing is possible; nothing requires it.

What a buyer can establish without a lab

Fresh: glossy, deep green leaflets that smell strongly when torn; yellowing and faint smell mean age. Wash them, and a dilute lemon soak removes more residue than tap water; cook them rather than serving them raw. Dried: USDA certified organic restricts synthetic pesticides at the farm, the most practical residue control a shopper can buy; green color shows gentle drying but not surviving aroma, since the magnesium oxide blanch used in published curry leaf drying methods preserves color by design. Capsules: if the Supplement Facts panel lists iron, it is an iron supplement; if it says "extract" without a ratio, it cannot be compared with any study.

What a lot's certificate should state

Botanical name with authority, plant part, country and region of origin, drying method and temperature, final moisture, and a multi-residue pesticide result at 0.01 mg per kg naming at least profenofos, chlorpyrifos and acephate. For an extract: solvent, drug-to-extract ratio and mahanimbine by a validated UPLC method such as Joshi's 2015 protocol. For an iron claim: iron by atomic absorption and a statement of where the iron comes from.

Special Considerations

Citrus greening and the fresh leaf

Curry leaf is a preferred host of the Asian citrus psyllid (Diaphorina citri), which spreads huanglongbing, or citrus greening. USDA Agricultural Research Service scientists at Fort Pierce, Florida described curry leaf and orange jasmine in 2018 as "often heavily colonized by the psyllid."

• APHIS Federal Order DA-2008-02 (January 11, 2008) extended the citrus greening quarantine to all of Florida, restricted interstate movement of host plants and plant parts other than fruit, curry leaf included, and required curry leaf for consumption leaving psyllid-quarantined areas to be fumigated with methyl bromide under APHIS treatment schedule T101-n-2, with irradiation allowed only for leaves from areas not quarantined for citrus greening.

• An APHIS order of October 6, 2009 prohibited seeds for planting of listed Rutaceae genera, Murraya among them, from 47 countries including India and Sri Lanka.

• In July 2009 a detector dog at a Fresno FedEx facility found a package of curry leaves carrying psyllids, one of which tested positive for the citrus greening bacterium (Western Farm Press, August 2009).

• APHIS Federal Order DA-2022-07 (May 12, 2022) set a protocol for moving fresh, mature rutaceous leaves for consumption, curry leaf included, out of quarantined areas: a compliance agreement, yellow sticky traps in drying areas, and "zero tolerance for the presence or indications of any life stage of the pest."

For a buyer, fresh curry leaf in a US store has usually been fumigated, irradiated or moved under a federal protocol. A 2011 petition to USDA's National Organic Program by Curry Love Inc., a Los Angeles curry sauce maker, described one Southern California grower with five trees producing about 15 pounds a year. Scarcity of the fresh leaf is regulatory, and it is part of why the dried and capsule forms sell.

Other countries

EU requirements from October 2014 ended imports of fresh curry leaves from outside the EU unless the source country is recognized as free of citrus greening; in August 2015 the UK's Defra said "imports of dried and frozen curry leaves are unaffected." In 2013 Australian officers at Melbourne airport found curry leaves carried by passengers from India infested with psyllid eggs and nymphs. University of California Master Gardeners in Santa Clara County advise home growers that leaves "should not be taken outside our local ACP quarantine zone."

The trial amounts, kept out of Recommended Dosages

Iyer and Mani's 12 g of dried powder daily was given for one month to 30 adults with diabetes under study conditions in Baroda in 1990, with no lasting effect. Farooq's 5 and 10 mg per kg of water extract went to 45 women with diabetes for 45 days. Sengupta's two capsules twice daily of a curry leaf and Tribulus formula went to 23 of the 46 randomized men with prostate symptoms in a supervised trial. Orgen-I's 500 mg capsule is an 18 mg iron dose given to anemic adults for 60 days. None is an amount a reader has any basis to take.

Research Status & Evidence Quality

Tier 1, controlled trials of curry leaf by itself in people

None that is randomized, placebo-controlled, blinded and published in full with a glucose or hair endpoint. Farooq 2023 (45 women, 45 days) reports significant fasting glucose and HbA1c reductions in an abstract with no values and no described control arm.

Tier 2, human uncontrolled, single-meal or formula studies

Iyer and Mani 1990, transient effect; Suganthi 2022, quasi-experimental; Senadheera and Ekanayake 2012, a single-meal glycemic index test; the curry leaf and Tribulus prostate trial; the null three-herb IBS crossover; a manufacturer's topical skin trial; and the Orgen-I trial, which concerns iron.

Tier 3, animal

Glucose lowering with water and solvent extracts in chemically induced diabetic rodents, weak or null results when the dried leaf itself was fed, alkaloid effects in high-fat-fed and db/db mice, and toxicity data that range from an LD50 of 316 mg per kg to no effect at 5,000 mg per kg depending on the extract.

Tier 4, in vitro

Amylase inhibition, muscle-cell glucose uptake, cytotoxicity, antioxidant assays and melanogenesis inhibition. The last is the only cell finding that speaks to a consumer claim, and it contradicts it.

Research Limitations

• No two human studies used the same preparation: powder, water extract, porridge, and powder of unstated dose.

• No human study reports how its leaf was dried or its alkaloid content, although drying alone moves beta-carotene 6.6-fold.

• Three of the five glucose studies are available to most readers only as abstracts or are unindexed in full, and none reports adverse events in its abstract.

• The author found no human pharmacokinetic study; every mechanism is a cell or rodent mechanism.

• No human hair research exists, and the one relevant cell study points the other way.

Summary & Key Takeaways

Bottom Line

Curry leaf (Murraya koenigii) is a citrus-family cooking leaf with useful calcium and beta-carotene, a large carbazole alkaloid chemistry, and a human blood sugar record too small, too short and too varied in preparation to support a supplement claim. The fresh leaf fried in fat is the form with the history and the chemistry intact; drying strips carotenoids and flavor compounds by method-dependent amounts no capsule label discloses. No human study supports the hair claims, and two products sold as curry leaf extract are, by their own numbers, iron supplements.

Key Safety Points

• An iron-standardized curry leaf extract is an iron supplement at 15 to 18 mg per capsule. Keep it from children, avoid it with hemochromatosis, and space it from levothyroxine, doxycycline, ciprofloxacin, levodopa and dolutegravir.

• With insulin or a sulfonylurea, any glucose-lowering preparation adds hypoglycemia risk. Tell the prescriber and watch the meter.

• Pesticide residue is the documented hazard of the leaf itself: profenofos to 25.63 mg per kg in a Kerala market sample, and Indian curry leaves under 50 percent EU border checks. Wash fresh leaves; prefer certified organic dried ones.

• Fresh leaves served raw have carried Salmonella: a 2013 Newcastle outbreak made 592 people ill, and 26 percent of imported curry leaf samples tested in England in 2017 were positive. Cook fresh leaves.

• No reproductive safety data exist for capsules or extracts.

• The longest monitored oral exposure to a curry leaf-only product is 60 days, for an iron extract; for a glucose purpose it is 45 days.

Special Note

The fresh leaf a South Indian cook fries in ghee and leaves on the plate is the form with the longest human history, the most aroma and, by the drying studies, the most intact carotenoids. It is also the form the US citrus quarantine makes hardest to buy, and the capsule is the form easiest to buy with the least behind it. A buyer who wants what curry leaf actually is should look for the fresh leaf, or grow a tree outside a quarantine zone.

Researched and drafted with AI assistance. Every claim verified against primary sources and human-reviewed before publication. Last reviewed: October 19, 2026. Corrections: reply to any issue.

This issue is educational and is not medical advice. If you take medication for diabetes or any other condition, or have a diagnosed condition, talk to a clinician before adding a curry leaf capsule or extract or changing anything you take.