Thirty-one trials, 2,145 participants with type 2 diabetes, obesity, or other metabolic diseases: brought together in a meta-analysis published in 2026, they show that nigella supplementation is accompanied on average by fasting blood glucose that is 18.62 mg/dL lower and glycated hemoglobin that is 0.56 points lower. However, the same authors found no effect on insulin or insulin resistance, and invite caution in interpreting these figures due to variable study quality and highly dispersed results, with heterogeneity of approximately 99%.
This guide brings together studies identified via PubMed on nigella, or black cumin, and blood glucose: meta-analyses and limitations, trials in diabetics and prediabetics, comparison with metformin, forms and doses, hypoglycemia and interactions with antidiabetic medications, then an approach to build with your doctor.
What the trials show : in people with type 2 diabetes, meta-analyses find an average reduction in fasting blood glucose of approximately 18 to 24 mg/dL and glycated hemoglobin of 0.44 to 0.71 points, with oil or seed powder, at doses of 0.9 to 5 g per day for 2 to 12 months, almost always in addition to medications. Insulin and insulin resistance indices do not change significantly. The trials are small and highly heterogeneous: heterogeneity exceeds 90% and the certainty of evidence is judged low to very low for glycated hemoglobin.
What you need to know before trying : nigella has never replaced a treatment in trials; compared to metformin, it was less effective in newly diagnosed patients. In rats, nigella oil increased exposure to a sulfonylurea by 29%, and thymoquinone enhanced the effect of glibenclamide. No human trials have measured these interactions: with antidiabetic treatment, any use is decided with your doctor, with enhanced monitoring of blood glucose.
- Nigella and blood glucose: what are we talking about?
- What meta-analyses show
- Heterogeneity and quality: reading the figures with caution
- Trials in type 2 diabetics
- Insulin and insulin resistance: a less clear effect
- Prediabetes: very limited data
- Nigella and metformin: in addition, never instead of
- Oil or powder: forms, doses, and durations
- Hypoglycemia and interactions: what is documented
- Proposed mechanisms, in animals and in the laboratory
- In practice: an approach guided by your doctor
- Frequently asked questions
Nigella and blood glucose: what are we talking about?
Nigella, Nigella sativa, is a ranunculaceae whose black seeds are called, depending on the region, black cumin, black caraway or kalonji. Studies use mainly theoil and seed powder ; its main studied compound is thymoquinone. Our general guide to nigella oil presents the plant and its uses; this article focuses on blood glucose.
The trials measure four markers. Fasting blood glucose reflects blood sugar in the morning, after a night without eating.Glycated hemoglobin, or HbA1c, expressed as a percentage, reflects average blood glucose over the past few months: it is the main reference for diabetes monitoring, and according to a 2021 review, it should be measured at least 3 months after the start of an intervention to see its full effect.Fasting insulin and the HOMA index, calculated from the two, provide information on insulin resistance and the pancreatic cells that produce it.
To put the figures in perspective: according to a 2021 review, a decrease of at least 0.5 points in glycated hemoglobin is clinically significant. Metformin alone lowers it by 1.12 points compared to placebo, and by 0.95 points when added to another oral treatment. In a large observational study of 3,642 type 2 diabetics, each point of glycated hemoglobin reduction was associated with 21% fewer diabetes-related complications, an association and not proof of causality.
What meta-analyses say
Since 2017, at least eight meta-analyses of controlled trials, on different populations (type 2 diabetes, prediabetes, metabolic syndrome, adults of all profiles), all find an average decrease in fasting blood glucose andglycated hemoglobin under nigella compared to control groups.
In type 2 diabetics alone, a meta-analysis of 16 trials published in 2025 finds lower fasting blood glucose of 21.43 mg/dL and lower glycated hemoglobin of 0.44 points, as well as a decrease in total cholesterol and LDL. It finds no effect on insulin, the HOMA index or weight. The largest review, published in 2025, brings together 82 studies and 5,026 participants with doses of 200 to 4,600 mg per day for 1 to 48 weeks, across all populations, and points in the same direction.
| Meta-analysis | Population and trials | Fasting blood glucose | Glycated hemoglobin |
|---|---|---|---|
| Musazadeh, 2026 | 31 trials, 2,145 participants with metabolic diseases | −18.62 mg/dL, I² 99.2% | −0.56 point, I² 98.6%, low certainty; no effect on insulin and HOMA |
| Karimi, 2025 | 16 trials, type 2 diabetes | −21.43 mg/dL | −0.44 point; no effect on insulin and HOMA |
| Shirvani, 2024 | 30 trials, adults | Effect size −1.71, heterogeneity 92.7% | Effect size −2.16, heterogeneity 95.7% |
| Saadati, 2022 | 11 trials, 666 participants, prediabetes and type 2 diabetes | −24.18 mg/dL, low certainty | −0.54 point, very low certainty |
| Hallajzadeh, 2020 | 50 trials, all populations | −15.18 mg/dL | −0.45 point |
| Askari, 2019 | 17 trials, all populations | −9.93 mg/dL | −0.57 point |
| Daryabeygi-Khotbehsara, 2017 | 7 trials including 3 non-randomized, type 2 diabetes | −17.84 mg/dL | −0.71 point, possible publication bias |
| Shabani, 2025 | 7 trials, metabolic syndrome | Effect size −0.8 | Effect size −0.37 |
A synthesis of meta-analyses published in 2021, covering 18 plants, ranks black seed among seven remedies associated with a drop in glycated hemoglobin of at least 0.5 point, alongside aloe vera, psyllium, and fenugreek.
When trials measure differently, meta-analyses report the difference between groups relative to the spread of measurements: 0.2 corresponds to a small effect, 0.5 to a moderate effect, 0.8 to a large effect. The values of −1.71 and −2.16 from the 2024 synthesis, unusually high and associated with heterogeneity exceeding 90%, warrant caution.
Heterogeneity and quality: read the numbers with caution
The concordance of meta-analyses does not equate to robustness. Theheterogeneity, which measures how much trial results diverge, is very high: 98.7% for fasting blood glucose and 94.4% for glycated hemoglobin in the 2022 meta-analysis on prediabetes and diabetes. In other words, the average obscures trials with very different results.
In 666 people with prediabetes or type 2 diabetes, black seed at 0.9 to 5 g per day for 2 to 6 months was associated with fasting blood glucose lower by 24.18 mg/dL and glycated hemoglobin lower by 0.54 points. The authors judge the certainty of evidence as weak for blood glucose and very weak for glycated hemoglobin, due to high heterogeneity and publication bias for glycated hemoglobin. The trials were small, with at most 114 participants, and all had been conducted in Iran, India, Egypt, or Saudi Arabia.
Saadati S, Naseri K, Asbaghi O, et al. Front Nutr 2022;9:977756. DOI: 10.3389/fnut.2022.977756
Publication biasis the tendency for favorable trials to be published more often than others: it was detected for glycated hemoglobin as early as the 2017 meta-analysis, then again in 2022. The preparations vary from one trial to another—oil, oil extract, seed powder—and their composition is rarely described: a 2022 systematic review of 17 clinical studies notes that only one precisely identified the plant material used.
A synthesis of reviews published in 2025, limited to trials versus placebo, is more stringent. It judges the quality of reviews on plants and diabetes as low to very low, and notes that the review retained for black seed did not compare groups with each other: in one trial, glycated hemoglobin decreased under black seed as under placebo, and in several trials fasting blood glucose, insulin, and HOMA index improved in both groups.
The Saudi one-year trial in 114 patients, often cited, is presented contradictorily: its abstract mentions groups constituted by convenience, its methods section describes randomization, and a second 2017 publication on the same cohort, under the same registration number, describes it as non-randomized, with allocation left to investigators. The 2022 meta-analysis nevertheless classifies it as randomized, over 12 weeks and as an oil extract, when it actually lasted one year with seed powder. This type of inconsistency partly explains the caution of quality assessments.
Trials in type 2 diabetics
In Iran, two double-blind trials tested 1 g of black seed oil per dayin two 500 mg capsules, for 8 weeks, described in one of the two as an oil extract. In 43 patients with a mean age of 53.5 years, fasting blood glucose and glycated hemoglobin decreased more than under sunflower oil used as placebo, as did cholesterol, triglycerides, waist circumference, and blood pressure, with no change in HOMA index. In 50 patients, the same dose lowered fasting blood glucose and blood lipids compared to placebo, as well as two markers of inflammation and oxidation.
These two trials used 1 g per day of oil or oil extract, equivalent to the amount of oil provided by 2 of our Egyptian black seed oil capsuleswith an additional 15 mg of vitamin E in our formula. They tested their own preparations, not our capsules: their results do not apply to any particular product.
In 114 Saudi patients with type 2 diabetes treated with oral antidiabetic medications, of whom 98 received sulfonylurea and metformin, 2 g per day of black seed powder in capsules decreased fasting blood glucose from 195 to 172 mg/dL and glycated hemoglobin from 8.6 to 8.2% over one year, while the placebo group, under activated charcoal, went from 8.2 to 8.5%. The difference between groups was significant at 3 and 6 months for fasting blood glucose, at 6 and 9 months for glycated hemoglobin, but no longer at 12 months. No adverse effects were noted.
Kaatabi H, Bamosa AO, Badar A, et al. PLoS One 2015;10(2):e0113486. DOI: 10.1371/journal.pone.0113486
The authors acknowledge that diet and physical activity were not monitored, and that the groups differed at baseline in insulin resistance and pancreatic cell function. The table also summarizes two trials in hemodialysis or diabetic nephropathy, with no notable adverse effects reported in hemodialysis.
| Trial | Population | Form, dose, and duration | Main result |
|---|---|---|---|
| Hadi, 2021, double-blind | 43 type 2 diabetics, Iran | Oil extract, 2 capsules of 500 mg per day, 8 weeks | Fasting blood glucose and HbA1c lower than placebo; HOMA unchanged |
| Kooshki, 2020, double-blind | 50 type 2 diabetics, Iran | Oil, 1,000 mg per day, 8 weeks | Fasting blood glucose and lipids lower than placebo |
| Kaatabi, 2015, single blind | 114 type 2 diabetics on oral treatment, Saudi Arabia | Seed powder, 2 g per day, 1 year | Significant difference between 3 and 9 months, greater at 12 months |
| Rahmani, 2022, double blind | 46 diabetics on hemodialysis, Iran | Oil, 2 g per day, 12 weeks | HbA1c and fasting blood glucose lower than with placebo |
| Ansari, 2017, open-label | Diabetic nephropathy stage 3 or 4, India | Oil, 2.5 mL per day, 12 weeks | Blood glucose and creatinine lower than with standard care alone |
| Moustafa, 2019, open-label | Recently diagnosed type 2 diabetes, Egypt | Oil in capsules, 1,350 mg per day, 3 months, versus metformin | Less effective than metformin on blood glucose and HbA1c |
| Mostafa, 2021, no placebo | 117 obese prediabetics, Egypt | Oil, 450 mg twice daily, 6 months | No significant difference with metformin or lifestyle program on most glycemic markers |
Insulin and insulin resistance: a less clear effect
The most recent meta-analysis, such as the 2025 one on type 2 diabetes, found no effect on fasting insulin or HOMA insulin resistance index, nor did the 2024 synthesis of 30 trials, with heterogeneities of 95 to 96%.
A few signals appear in subgroups. In the 2022 meta-analysis, the HOMA index decreased by 0.80 when supplementation lasted more than 8 weeks, and the only trial conducted in prediabetics, compared to a lifestyle program, showed a decrease in insulin and HOMA index. The 2025 meta-analysis on type 2 diabetes found an improvement in HOMA index with doses greater than 1 g per day, with oil, and over durations of 8 weeks or less. These subgroups involve few trials.
Physical activity could matter more. In an 8-week Iranian trial of 40 people with type 2 diabetes, resistance training alone and black seed alone each lowered HOMA index, insulin, and blood glucose, but their combination most improved HOMA index, insulin, and an inflammation marker. This small trial remains to be confirmed.
Prediabetes: very little data
For prediabetes, blood glucose above normal without reaching the diabetes threshold, data are scarce. The only available trial was conducted in Egypt in 117 obese and prediabetic people, divided into three groups for 6 months: a lifestyle program with controlled diet and exercise, metformin at 500 mg twice daily, or black seed oil capsules at 450 mg twice daily, totaling 900 mg per day.
Black seed did not distinguish itself significantly from metformin on weight and most glycemic markers, nor from the lifestyle program on most of them; the lifestyle group achieved better pancreatic cell function. Black seed more improved lipids and an inflammation marker. Without a placebo group, one cannot know what share of the improvements belongs to it.
Among 3,234 prediabetic adults followed for an average of 2.8 years, a program targeting at least 7% weight loss and 150 minutes of physical activity per week reduced diabetes onset by 58% compared to placebo, and metformin at 850 mg twice daily by 31%. The lifestyle program proved significantly more effective than metformin.
Knowler WC, Barrett-Connor E, Fowler SE, et al. N Engl J Med 2002;346(6):393-403. DOI: 10.1056/NEJMoa012512
In the case of prediabetes, the best-demonstrated tool remains lifestyle modification, and then, if the physician deems it useful, medication. No trial reviewed measures whether black seed delays the onset of diabetes. Our article on elevated blood sugar reviews other plants.
Black seed and metformin: in addition, never instead of
In most trials, black seed was added to medications already being taken, sulfonylureas, metformin, or both: these are adjunctive effects. Only one team tested it alone, against metformin, in patients newly diagnosed with diabetes.
In Egyptian patients with newly diagnosed type 2 diabetes, 1,350 mg per day of black seed oil in capsules for 3 months proved less effective than metformin in lowering fasting blood glucose, blood glucose two hours after meals, and glycated hemoglobin. Weight, waist circumference, and body mass index decreased comparably, and black seed was well tolerated.
Moustafa HAM, El Wakeel LM, Halawa MR, et al. Endocrine 2019;65(2):286-294. DOI: 10.1007/s12020-019-01963-4
The orders of magnitude point in the same direction: meta-analyses attribute to black seed an average reduction of 0.44 to 0.71 points in glycated hemoglobin, whereas metformin alone lowers this value by 1.12 points compared to placebo. A 2022 systematic review reports a 90-day open trial where 50 or 100 mg of isolated thymoquinone, added to 1,000 mg of metformin, lowered glycated hemoglobin more than metformin alone, from 7.2 to 6.7% with 50 mg and from 7.2 to 6.8% with 100 mg, versus 7.3 to 7.1%. This isolated compound is neither oil nor powder: the result does not translate.
A 2025 synthesis on plants in type 2 diabetes recommends using them only as a complement to treatment, after shared decision-making with the physician, as the useful doses and durations have not been established. No trial has tested replacing an antidiabetic medication with black seed.
Oil or powder: forms, doses, and durations
Trials primarily usedoil, in capsules or by the spoonful, and more rarely seed powder in capsules. Doses range from 0.9 to 5 g per day according to the 2022 meta-analysis, and up to 3 g per day for powder and 5 mL per day for oil according to the 2022 systematic review.
Data on the best form contradict each other. In the 2019 meta-analysis, oil lowered fasting blood glucose more than powder. In the 2017 one, triglycerides increased with powder and decreased with oil. The 2021 synthesis retained powder at 2 g per day as the most effective preparation, whereas the 2025 synthesis on type 2 diabetes associates oil and doses higher than 1 g with better glycated hemoglobin. No form can be declared superior.
The dose is no more settled. A 12-week trial published in 2010 by Bamosa and colleagues, without a placebo group, compared 1, 2, and 3 g per day of seed powder in type 2 diabetics: according to its abstract, 3 g provided no additional benefit compared to 2 g.
Regarding duration, the 2025 meta-analysis found a decrease in fasting blood glucose mainly beyond 8 weeks, the 2022 one a decrease in the HOMA index beyond 8 weeks. Since glycated hemoglobin requires at least 3 months to reflect a change, shorter trials may underestimate its evolution.
For the powder, our organic black seed powder consists of ground organic black seeds; the year-long Saudi trial used 2 g per day of seed powder in capsules, a different preparation whose results cannot be transposed. For liquid oil, trials used 1.5 to 5 mL per day; our Ethiopian black seed oil is used at 1 to 3 teaspoons per day, and under treatment, the quantity is decided with the physician.
Hypoglycemia and interactions: what is documented
In trials, black seed was well tolerated : in the 2017 meta-analysis, six out of seven trials reported no adverse effects, the seventh reported mild digestive disturbances; in the isolated thymoquinone trial combined with metformin, 15 to 28.6% of patients reported digestive effects, diarrhea or abdominal pain, compared to 10.5% under metformin alone, none being serious. In the year-long trial, where 98 of 114 patients were taking a sulfonylurea and metformin, no adverse effects were noted, and kidney and liver function tests remained normal. Two isolated observations, however, describe kidney damage: in 2013, acute kidney injury associated with black seed in a diabetic patient, and in 2024, acute kidney injury with rhabdomyolysis, muscle damage, and liver toxicity after consumption of black seed oil. These are isolated cases whose causal link has not been established; in case of kidney disease, use should be discussed with the physician.
Adverse effect reporting remains incomplete: the 2025 synthesis considers safety data inadequate, notes the lack of interaction data with antidiabetic medications, and recommends a Careful monitoring of hypoglycemia when plants are combined with them. For antidiabetic drugs, the only available interaction data come from animal and laboratory studies, and they point toward an additive effect.
In rats, black seed oil administered with gliclazide, a hypoglycemic sulfonylurea, increased the drug's bioavailability by 29% and reduced its elimination by 20%. In healthy rats, pretreatment with black seed oil enhanced blood glucose reduction by up to 50% compared to gliclazide alone, an effect not found in insulin-resistant rats.
Adiwidjaja J, Sasongko L. Biopharm Drug Dispos 2021;42(8):359-371. DOI: 10.1002/bdd.2300
In diabetic rats, thymoquinone combined with glibenclamide, another sulfonylurea, lowered blood glucose by 53 to 56.2% compared to 47.4% with glibenclamide alone, and increased drug exposure by 52.5% after prolonged administration by inhibiting liver enzymes that eliminate it, according to a 2022 systematic review. In rats again, black seed inhibited a liver enzyme that breaks down tolbutamide, a sulfonylurea. Hence the recommendation for caution.
Beyond diabetes, two other interactions are documented outside of humans. In the laboratory, thymoquinone inhibits the breakdown of warfarin, an anticoagulant, and the authors estimate that taking more than 1 g of black seed oil per day could alter its fate in the body. In rabbits, black seed reduced exposure to cyclosporine, an immunosuppressant, by 55.9%. Our article on the dangers of black seed oil details all the precautions.
With a hypoglycemic sulfonylurea, a meglitinide, or insulin, which can cause hypoglycemia on their own, adding black seed should only be done with your doctor's approval, who may plan more frequent monitoring and adjust your treatment. Never change a dose on your own, and report any plant or supplement to your doctor.
The proposed mechanisms, in animals and in the laboratory
These hypotheses come from studies in animals or in cells, often at very high doses: they prove nothing in humans.
Less glucose absorbed. On a rat intestine fragment, an aqueous extract of seeds inhibited sodium-dependent glucose transport by more than 80%; in rats, 2 g per kilogram of body weight per day for 6 weeks improved glucose tolerance as well as metformin.
Better insulin sensitivity. In rats fed a 60% fructose diet, thymoquinone, at 25 to 100 mg per kilogram per day for 42 days, prevented blood glucose elevation, glucose intolerance, and insulin resistance, with effects comparable to pioglitazone, by acting on liver receptors called PPARs. The authors of the 2022 meta-analysis also cite reduced glucose production by the liver and activation of an enzyme that regulates cellular energy, AMPK.
Protected pancreatic cells. On insulin-producing cells and pancreatic islets of rodents, thymoquinone and black seed extracts increased glucose-triggered insulin secretion and preserved it against chronic glucose excess. In humans, fasting insulin does not change significantly. Our article on thymoquinone provides an update on this compound.
In practice: an approach guided by your doctor
Average effects remain modest. Here is an approach based on the parameters of trials, to be validated with your doctor; intake guidelines are practical advice, not study results.
Egyptian black seed oil capsules are not recommended for children, adolescents, or pregnant or nursing women. Ethiopian black seed oil is not recommended for children and pregnant women, and requires medical advice during breastfeeding. Do not exceed the dose indicated on the product.
Cold-pressed black seed oil (Nigella sativa) from Egypt, with vitamin E, in tasteless capsules. Two capsules per day with meals provide 1 g of black seed oil and 15 mg of vitamin E, an easy addition to your routine after consulting with your doctor if you are taking other medications.
View black seed capsulesDo you prefer liquid oil? Discover our Ethiopian black seed oil, cold-pressed and unfiltered.
Frequently asked questions
Does black seed lower blood sugar?
In people with type 2 diabetes, meta-analyses find on average fasting blood sugar approximately 18 to 24 mg/dL lower with black seed, almost always added to medications. The effect remains modest and uncertain.
Is black seed oil effective against type 2 diabetes?
It has been associated with an average reduction of 0.44 to 0.71 points in glycated hemoglobin as a supplement to treatment, with no clear effect on insulin. In direct comparison in newly diagnosed patients, 1,350 mg of oil per day was less effective than metformin. It does not treat diabetes and does not replace any medication.
What dose of black seed was used in diabetes trials?
Trials used 0.9 to 5 g per day, most commonly 1 g of oil per day in two 500 mg capsules, or 2 g of seed powder per day, for 8 weeks to 1 year. No optimal dose has been established, and with treatment the amount should be decided with your doctor.
Can you take black seed with metformin?
In several trials, black seed was added to metformin, alone or combined with a sulfonylurea, with no serious adverse effects reported. However, no human trial has measured an interaction with antidiabetic drugs. The decision should be made with your doctor, with monitoring of blood sugar.
Can black seed cause hypoglycemia?
The trials reviewed do not report hypoglycemia, but adverse effect reporting was often incomplete. In rats, black seed oil increased gliclazide exposure by 29% and, in healthy rats, enhanced its effect on blood sugar. With a sulfonylurea, meglitinide, or insulin, enhanced monitoring is essential.
Is black cumin the same as black seed?
Yes. Nigella sativa is called black seed, black cumin, black caraway, black seeds, or kalonji depending on the region.
Does black seed help with prediabetes?
Data are very limited. In a 6-month Egyptian trial of 117 obese and prediabetic people, 900 mg of oil per day did not differ significantly from metformin or lifestyle changes on most blood sugar markers, with no placebo group. Lifestyle remains the best-established tool.
How long does it take to see an effect on glycated hemoglobin?
Glycated hemoglobin reflects blood sugar over recent months: a 2021 review recommends measuring it at least 3 months after beginning an intervention. In meta-analyses, a reduction in fasting blood sugar appears mainly beyond 8 weeks, and in the 1-year trial the difference from placebo was no longer significant at 12 months.
Does black seed improve insulin resistance?
Not clearly in humans: the main meta-analyses find no effect on fasting insulin or the HOMA index. A reduction in this index appears only in certain subgroups, beyond 8 weeks.
Who should avoid black seed?
Black seed products are not recommended for children and pregnant women, and capsules are also not recommended for adolescents and during breastfeeding. Medical advice is necessary when taking antidiabetic drugs, anticoagulants like warfarin, immunosuppressants like cyclosporine, or in case of kidney disease.
Sources
The studies cited below were identified via PubMed.
- Musazadeh V, Jahangir M, Mahmoudinezhad M, et al. Effect of Nigella sativa supplementation on cardiometabolic health in patients with metabolic diseases: systematic review and meta-analysis evaluated by the GRADE method. Endocrinology, Diabetes and Metabolism, 2026;9(2):e70207. DOI
- Willcox ML, Elugbaju C, Al-Anbaki M, et al. Efficacy of medicinal plants on glycemic control in type 2 diabetes: synthesis of meta-analyses from clinical trials. Frontiers in Pharmacology, 2021;12:777561. DOI
- Stratton IM, Adler AI, Neil HA, et al. Association between blood glucose and macrovascular and microvascular complications of type 2 diabetes: prospective observational study. BMJ, 2000;321(7258):405-412. DOI
- Karimi M, Pirzad S, Pourfaraji SMA, et al. Effects of black cumin (Nigella sativa L.) on cardiometabolic indices in type 2 diabetic patients: systematic review and meta-analysis of randomized trials. Complementary Therapies in Medicine, 2025;90:103174. DOI
- Jafari A, Mardani H, Faghfouri AH, et al. Does Nigella sativa supplementation improve cardiovascular risk factors? Systematic review evaluated by the GRADE method and dose-response meta-analysis of 82 randomized trials. Pharmacological Research, 2025;219:107882. DOI
- Shirvani S, Falahatzadeh M, Oveili E, et al. Effect of Nigella sativa supplementation on glycemic status in adults: updated systematic review and meta-analysis of randomized trials. Prostaglandins and Other Lipid Mediators, 2024;174:106885. DOI
- Saadati S, Naseri K, Asbaghi O, et al. Nigella sativa supplementation improves cardiometabolic indicators in prediabetic and type 2 diabetic individuals: systematic review and meta-analysis of randomized trials. Frontiers in Nutrition, 2022;9:977756. DOI
- Hallajzadeh J, Milajerdi A, Mobini M, et al. Effects of Nigella sativa on glycemic control, lipid profile, and markers of inflammation and oxidative stress: systematic review and meta-analysis of randomized trials. Phytotherapy Research, 2020;34(10):2586-2608. DOI
- Askari G, Rouhani MH, Ghaedi E, et al. Effect of black cumin (Nigella sativa) supplementation on glycemic control: systematic review and meta-analysis of clinical trials. Phytotherapy Research, 2019;33(5):1341-1352. DOI
- Daryabeygi-Khotbehsara R, Golzarand M, Ghaffari MP, Djafarian K. Nigella sativa improves glucose homeostasis and serum lipids in type 2 diabetes: systematic review and meta-analysis. Complementary Therapies in Medicine, 2017;35:6-13. DOI
- Shabani M, Ghavidel F, Rajabian A, et al. Effect of Nigella sativa consumption on lipid profile and glycemic indices in patients with metabolic syndrome: systematic review and meta-analysis of randomized trials. Current Medicinal Chemistry, 2025;32(18):3638-3650. DOI
- Mahomoodally MF, Aumeeruddy MZ, Legoabe LJ, et al. Nigella sativa L. and its active compound, thymoquinone, in the clinical management of diabetes: systematic review. International Journal of Molecular Sciences, 2022;23(20):12111. DOI
- Li E, Maunder A, Liu J, et al. Efficacy and safety of medicinal plants for glycemic control and insulin resistance in type 2 diabetes: umbrella review. BMC Complementary Medicine and Therapies, 2025;25(1):341. DOI
- Kaatabi H, Bamosa AO, Badar A, et al. Nigella sativa improves glycemic control and attenuates oxidative stress in type 2 diabetic patients: participant-blinded placebo-controlled clinical trial. PLoS One, 2015;10(2):e0113486. DOI
- Badar A, Kaatabi H, Bamosa A, et al. Effect of one-year Nigella sativa supplementation on lipids, blood pressure, and heart rate in type 2 diabetics on oral antidiabetic medications: non-randomized clinical trial. Annals of Saudi Medicine, 2017;37(1):56-63. DOI
- Hadi S, Daryabeygi-Khotbehsara R, Mirmiran P, et al. Effect of Nigella sativa oil extract on cardiometabolic risk factors in type 2 diabetes: double-blind randomized placebo-controlled trial. Phytotherapy Research, 2021;35(7):3747-3755. DOI
- Kooshki A, Tofighiyan T, Rastgoo N, et al. Effect of Nigella sativa oil supplement on cardiovascular risk factors in type 2 diabetic patients. Phytotherapy Research, 2020;34(10):2706-2711. DOI
- Rahmani A, Niknafs B, Naseri M, et al. Effect of Nigella sativa oil on oxidative stress, inflammation, and glycemic control in hemodialyzed diabetic patients: double-blind randomized trial. Evidence-Based Complementary and Alternative Medicine, 2022;2022:2753294. DOI
- Ansari ZM, Nasiruddin M, Khan RA, Haque SF. Protective role of Nigella sativa in diabetic nephropathy: randomized clinical trial. Saudi Journal of Kidney Diseases and Transplantation, 2017;28(1):9-14. DOI
- Moustafa HAM, El Wakeel LM, Halawa MR, et al. Effect of Nigella sativa oil compared to metformin on glycemic control and biological parameters in newly diagnosed type 2 diabetic patients. Endocrine, 2019;65(2):286-294. DOI
- Mostafa TM, Hegazy SK, Elnaidany SS, et al. Nigella sativa, a promising intervention for metabolic and inflammatory disorders in obese prediabetic individuals: a study comparing Nigella sativa to lifestyle change and metformin. Journal of Diabetes and Its Complications, 2021;35(7):107947. DOI
- Jangjo-Borazjani S, Dastgheib M, Kiyamarsi E, et al. Effects of resistance training and Nigella sativa in type 2 diabetes: consequences on metabolic markers, low-grade inflammation and liver enzymes. Archives of Physiology and Biochemistry, 2023;129(4):913-921. DOI
- Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. The New England Journal of Medicine, 2002;346(6):393-403. DOI
- Arslan E, Sayin S, Demirbas S, et al. Acute kidney injury associated with Nigella sativa in a diabetic patient: clinical observation. Journal of Integrative Medicine, 2013;11(1):64-66. DOI
- Sener K, Cakir A, Yesiloglu O, et al. Rhabdomyolysis and acute kidney injury after consumption of nigella oil. Toxicon, 2024;245:107787. DOI
- Adiwidjaja J, Sasongko L. Effect of Nigella sativa oil on the pharmacokinetics and pharmacodynamics of gliclazide in rats. Biopharmaceutics and Drug Disposition, 2021;42(8):359-371. DOI
- Korashy HM, Al-Jenoobi FI, Raish M, et al. Effect of medicinal plants such as Nigella sativa, Trigonella foenum-graecum and Ferula asafoetida on the expression of cytochrome P450 2C11 gene in rat liver. Drug Research, 2015;65(7):366-372. DOI
- Wang Z, Wang Z, Wang X, et al. Potential risk of interaction between thymoquinone and warfarin. Chemico-Biological Interactions, 2022;365:110070. DOI
- Al-Jenoobi FI, Al-Suwayeh SA, Muzaffar I, et al. Effects of Nigella sativa and Lepidium sativum on cyclosporine pharmacokinetics. BioMed Research International, 2013;2013:953520. DOI
- Meddah B, Ducroc R, El Abbes Faouzi M, et al. Nigella sativa inhibits intestinal glucose absorption and improves glucose tolerance in rats. Journal of Ethnopharmacology, 2009;121(3):419-424. DOI
- Prabhakar P, Reeta KH, Maulik SK, et al. Protective effect of thymoquinone against metabolic syndrome induced by a high-fructose diet in rats. European Journal of Nutrition, 2015;54(7):1117-1127. DOI
- Gray JP, Burgos DZ, Yuan T, et al. Thymoquinone, an active compound from Nigella sativa, normalizes insulin secretion from pancreatic beta cells subjected to excess glucose by regulating malonyl-CoA. American Journal of Physiology. Endocrinology and Metabolism, 2016;310(6):E394-E404. DOI
