Table of Contents
- Current evidence position
- Key safety points
- Brad's videos on this topic
- Overview
- Forms and Bioavailability
- Evidence for Benefits
- Recommended Dosing
- Safety and Side Effects
- Drug Interactions
- Dietary Sources
- References
Current evidence position
Brad has not made a video on this topic; this is a summary of the evidence, not his view. A 2025 review of 82 randomized trials with 5026 participants found that black seed (Nigella sativa) improved weight, blood pressure, blood sugar, cholesterol and inflammation markers, and called it a promising add-on therapy for heart disease risk factors [72]. The trials used 200 to 4600 mg a day for 1 to 48 weeks, and the thymoquinone content of commercial oils varies widely [72, 23]. Black seed can lower fasting blood sugar and blood pressure, a laboratory study predicts that more than 1 g a day of the oil might affect warfarin, and case reports link it to kidney injury, liver injury and very low platelet counts [34, 26, 76, 74, 66].
Key safety points
- A laboratory study predicts that black seed oil at more than 1 g a day might change how the body handles warfarin, and case reports describe a severe fall in platelets and a large bleed under the skin in people taking it [76, 66, 77]. If you take warfarin or an antiplatelet drug, talk to your doctor first.
- It can lower fasting blood sugar and blood pressure [34, 26]. If you take diabetes or blood pressure medicines, ask your doctor first and check your levels more often.
- Case reports link it to acute kidney failure, and to kidney injury with muscle breakdown and liver damage [75, 74]. If you have kidney or liver disease, ask your doctor first. Stop it and see your doctor if you become unwell while taking it.
- One case report linked it to serotonin syndrome after an endoscopic procedure [65]. Tell your surgeon and anaesthetist that you take it.
- Its safety in pregnancy and breastfeeding has not been established, and its volatile oil affected uterine muscle in animal tissue [78]. Avoid it while pregnant or breastfeeding.
- On the skin it has caused contact dermatitis [5], and case reports describe blistering reactions to the oil and to a swallowed supplement [79, 81]. For a widespread blistering rash or peeling skin, stop black seed and call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.
Brad's videos on this topic
None yet.
1. Overview
Black seed oil comes from the seeds of Nigella sativa, an annual flowering plant in the Ranunculaceae family [1, 2], native to southwest Asia [2]. Its seeds and oil have a long history of use in food and in traditional medicine, including the Unani, Tibb and Ayurveda systems [1]. In Islamic literature, black seed is considered one of the greatest forms of healing medicine [1].
Black seed goes by several names, including black cumin, black caraway and kalonji in South Asia [22].
The fixed oil is mostly linoleic acid, which is an omega-6 fat. One analysis found linoleic acid (55.6%), oleic acid (23.4%) and palmitic acid (12.5%) as the main fatty acids [70], and another found linoleic acid (50.2%) and oleic acid (19.9%) [7]. The seeds also contain essential oil, proteins, alkaloids and saponin [5].
Thymoquinone is the main active compound of the essential oil, and it is also present in the fixed oil [5, 11]. Laboratory studies have reported antioxidant, anti-inflammatory, immunomodulatory, antimicrobial and anti-tumor effects for thymoquinone [11]. Whether these laboratory effects carry over to people is still being studied. Related compounds in the oil include dithymoquinone, thymohydroquinone and thymol [12].
The oil can be extracted by cold pressing, supercritical fluid extraction or solvent methods, and its oxidative stability is very low, with heat and light affecting it [71].
A 2025 review of 82 randomized trials found that black seed improved several heart disease risk factors, including weight, blood pressure, blood sugar and cholesterol [72]. A 2016 overview noted that only limited non-clinical safety studies had been reported, and called for standardised dosage forms and formal studies of its safety [22].
2. Forms and Bioavailability
Black seed products differ in what they contain, and the form can matter: a meta-analysis found a greater blood-pressure effect with powder than with oil [26], while another found a greater effect of the oil on total and LDL cholesterol [37].
Black Seed Oil (Liquid)
The oil carries the full fatty acid profile plus thymoquinone [70, 71]. Thymoquinone content in commercial oils and capsules varied from 3.08 to 809.4 mg/100 g in one analysis [23].
One trial gave 5 ml of the oil a day in a honey-based formulation [49].
Black Seed Oil Capsules (Softgels)
Softgel capsules contain the oil in measured doses. Trials have used 450 mg twice daily [35] and 500 mg twice daily [42].
Black Seed Powder (Ground Seeds)
Ground black seed powder contains the whole seed. A meta-analysis of 11 trials found that powder lowered blood pressure more than oil did [26]. For cholesterol, the oil had a greater effect on total and LDL cholesterol, while a rise in HDL cholesterol was seen only with powder [37]. A trial gave 1 g, 2 g or 3 g of seed with omeprazole [50].
Black Seed Extract
Extracts are made from the seeds, and their thymoquinone content varies. One trial in older adults with high blood pressure gave 300 mg of extract, twice a day, for 28 days and found no proven blood-pressure benefit [84].
Topical Black Seed Oil
Black seed can also be applied to the skin. One acne trial used a hydrogel standardized on thymoquinone, applied morning and evening for 60 days [29]. In a knee osteoarthritis trial, 2.5 mL of oil applied three times a day lowered the inflammation marker hs-CRP compared with placebo [30]. Contact dermatitis after topical use has been reported in two people [5].
Bioavailability Considerations
Thymoquinone content varies widely between products. An analysis of six bottled oils and five oil capsules found 3.08 to 809.4 mg/100 g [23]. The authors called for black seed products to be regulated for thymoquinone content so consumers know what they are buying [23].
Comparison Table
| Form | Doses used in trials | Key points | Limits |
|---|---|---|---|
| Liquid oil | 5 ml of oil by mouth each day [49]; 2.5 mL by mouth twice a day [30] | Full fatty acid profile; greater cholesterol effect than powder [37] | Low oxidative stability [71] |
| Oil capsules (softgels) | 450 mg or 500 mg twice daily [35, 42] | Measured dose | Thymoquinone content varies [23] |
| Seed | 1 to 3 g a day [50] | Powder lowered blood pressure more than oil [26] | |
| Seed extract | 300 mg of seed extract, twice daily [84] | Concentrated | No proven blood-pressure benefit in one trial [84] |
| Topical (hydrogel or oil) | Twice daily [29]; three times a day [30] | Studied for acne and knee pain | Contact dermatitis reported [5] |
3. Evidence for Benefits
Most clinical trials of black seed are small and short. A 2025 review pooled 82 randomized trials lasting 1 to 48 weeks [72]. The sections below go through the evidence by condition.
Blood Sugar and Diabetes
Glycemic control in type 2 diabetes and prediabetes is among the most studied uses of black seed.
Meta-analysis of type 2 diabetes trials: A 2017 meta-analysis pooled seven trials in type 2 diabetes. Black seed lowered fasting blood sugar (-17.84 mg/dl, 95% CI -21.19 to -14.49) and HbA1c (-0.71%, 95% CI -1.04 to -0.39) (Daryabeygi-Khotbehsara et al., Complement Ther Med, 2017) [34].
Prediabetes comparison with metformin: A trial in 117 obese adults with prediabetes compared black seed oil softgels (450 mg twice daily), metformin (500 mg twice daily) and lifestyle change for six months. Black seed oil was statistically similar to metformin for weight and blood sugar measures, and lifestyle change gave the highest HOMA-B, a marker of insulin-producing cell function (Mostafa et al., J Diabetes Complications, 2021) [35].
Cardiometabolic meta-analysis: A 2025 meta-analysis of 16 trials in type 2 diabetes found lower fasting blood glucose (-21.43 mg/dL) and HbA1c (-0.44), but no effect on blood sugar after meals, fasting insulin, triglycerides, HDL cholesterol, liver enzymes, creatinine or body weight [36].
Summary: Black seed oil or powder may lower fasting blood sugar and HbA1c in people with type 2 diabetes or prediabetes. It is not a replacement for diabetes medicines.
Cholesterol and Lipids
Meta-analysis of 17 trials: A 2016 meta-analysis of 17 randomized trials found that black seed lowered total cholesterol (-15.65 mg/dL), LDL cholesterol (-14.10 mg/dL) and triglycerides (-20.64 mg/dL), with no effect on HDL cholesterol. The oil had a greater effect on total and LDL cholesterol than the powder, and HDL rose only with powder (Sahebkar et al., Pharmacol Res, 2016) [37].
Hashimoto's disease subgroup: In a trial of 40 people with Hashimoto's thyroiditis, powdered black seed for 8 weeks lowered LDL cholesterol and triglycerides and raised HDL cholesterol within the black seed group, not tested against placebo; placebo changed none of them (Farhangi et al., Lipids Health Dis, 2018) [38].
Summary: Black seed may lower total cholesterol, LDL and triglycerides. The effects are smaller than those of statins.
Blood Pressure
Meta-analysis of 11 trials: A 2016 meta-analysis of 11 randomized trials in 860 people, some with high blood pressure and some without, showed that black seed lowered systolic blood pressure by 3.26 mmHg and diastolic by 2.80 mmHg more than control, after an average of 8.3 weeks. Powder lowered blood pressure more than oil (Sahebkar et al., J Hypertens, 2016) [26].
Interaction with antihypertensive medications: Because black seed can lower blood pressure [26], it may add to the effect of blood pressure medicines. If you take them, check your blood pressure more often.
Seed extract trial: In 76 older adults with hypertension, 300 mg of extract, twice a day, for 28 days did not lower blood pressure more than placebo [84].
Summary: Black seed powder may lower blood pressure slightly. The effect of the oil and of extracts is less certain.
Weight Loss
Meta-analyses of 11 and 13 trials: A meta-analysis of 11 studies found that black seed reduced body weight by 2.11 kg compared with placebo (Namazi et al., J Ethnopharmacol, 2018) [27]. A second, of 13 randomized trials with 875 people, found a weight loss of 1.76 kg but no significant change in waist size (Mousavi et al., Complement Ther Med, 2018) [28]. Both noted high variation between studies.
Type 2 diabetes: The 2025 meta-analysis of 16 trials in type 2 diabetes found no effect on body weight [36].
Summary: Black seed may produce a small weight loss. It is an add-on to diet and exercise, not a weight-loss treatment.
Asthma
Two placebo-controlled trials suggest that black seed may improve asthma control when added to usual asthma medicines:
Black seed oil trial: In 80 adults with asthma, black seed oil capsules (500 mg twice daily) for 4 weeks improved Asthma Control Test scores (21.1 versus 19.6) and lowered blood eosinophils compared with placebo. The gain in lung function was not significant (Koshak et al., Phytother Res, 2017) [42].
Black seed trial (1 or 2 g/day): In partly controlled asthma, groups given 1 and 2 g/day of black seed for 3 months, with usual inhalers, improved some lung function measures, and fewer people had flare-ups in the 1 g group (Salem et al., Ann Saudi Med, 2017) [41].
Lung function meta-analysis: A meta-analysis of four trials found improved Asthma Control Test scores and FEV1, but no effect on peak expiratory flow [44].
Mechanism: Black seed has been reported to have anti-inflammatory and bronchodilator effects [41].
Summary: Black seed at 1 to 2 g a day may help control asthma alongside standard medicines. The evidence comes from a few small trials.
Thyroid (Hashimoto's Disease)
Hashimoto's disease is an autoimmune condition and the most common cause of an underactive thyroid. A trial of 40 people aged 22 to 50 years with the condition tested powdered black seed or placebo daily for 8 weeks. Black seed lowered TSH and anti-thyroid peroxidase (anti-TPO) antibodies, raised T3, and reduced body weight, with none of these changes in the placebo group [45].
The same trial found lower LDL cholesterol and triglycerides and higher HDL cholesterol within the black seed group, not tested against placebo (Farhangi et al., Lipids Health Dis, 2018) [38].
The trial used powdered seed, not oil [45].
Summary: Powdered black seed may lower thyroid antibodies and TSH in Hashimoto's disease. This is a single small trial and needs to be repeated.
Inflammation and Oxidative Stress
Systematic review of inflammatory markers: A 2020 meta-analysis of 12 trials found that black seed lowered C-reactive protein (CRP) and malondialdehyde, an oxidative stress marker, and raised total antioxidant capacity, with no significant effect on TNF-alpha [73].
Thymoquinone and cytokines: A review of laboratory and animal studies describes how black seed and thymoquinone change inflammation and immune responses [47].
Osteoarthritis evidence: A trial of 45 people with knee osteoarthritis compared oral black seed oil (2.5 mL twice a day), the oil applied to the knee (2.5 mL three times a day) and placebo for 6 weeks. Both oral and topical oil lowered hs-CRP compared with placebo, and both improved quality of life (Amirtaheri Afshar et al., Food Sci Nutr, 2023) [30]. A 2024 systematic review of six trials in 370 people with knee osteoarthritis found that topical oil eased pain better than placebo in three trials, while oral oil helped in only one of two; it judged the studies low quality and the findings conflicting [82].
Summary: Black seed may lower CRP and oxidative stress markers. Its effect on osteoarthritis pain is uncertain.
Gastric Ulcers and H. pylori
Black seed has been tested alongside standard treatment for Helicobacter pylori infection and dyspepsia (indigestion) [48, 49, 50]:
- In 51 people with H. pylori and functional dyspepsia, adding 2 g a day of black seed to quadruple therapy for 8 weeks gave more eradication than placebo (Alizadeh-Naini et al., Phytother Res, 2020) [48].
- In 70 people with functional dyspepsia on acid-lowering treatment, the oil, 5 ml in a honey-based formulation, daily for 8 weeks, lowered dyspepsia scores and the rate of H. pylori infection compared with placebo (Mohtashami et al., J Ethnopharmacol, 2015) [49].
- In 88 people with H. pylori, eradication rates with standard triple therapy and with 1 g, 2 g or 3 g of black seed plus omeprazole were 82.6, 47.6, 66.7 and 47.8%; only the 2 g dose was not significantly different from triple therapy (Salem et al., Saudi J Gastroenterol, 2010) [50].
These trials were small, and in each, black seed was given with other drugs or with honey [48, 49, 50].
Summary: Black seed may help clear H. pylori when added to standard treatment. The evidence does not support it as a stand-alone treatment.
Acne Vulgaris
In a trial of 60 people with acne vulgaris, a black seed hydrogel standardized on thymoquinone and used twice a day for 60 days cut the acne severity score by 78% compared with 3.3% for placebo. Comedones, papules and pustules fell significantly, and no adverse events were recorded (Soleymani et al., Phytother Res, 2020) [29].
Broader dermatological evidence: A meta-analysis of 14 trial records in skin conditions, including atopic dermatitis, psoriasis, vitiligo, eczema and acne, gave an odds ratio of 4.59 (95% CI 2.02 to 10.39) in favour of black seed [51].
Summary: Topical black seed showed large effects on acne in one trial. Larger trials are needed.
Skin Conditions (Beyond Acne)
Beyond acne, black seed has been studied for skin conditions such as atopic dermatitis, psoriasis, vitiligo, warts and eczema [51].
The meta-analysis authors judged that black seed may help, but that its effect still needs further trials [51].
Applied to the skin, the oil caused contact dermatitis in two reported cases [5].
COVID-19
Black seed has been tested for COVID-19 in two randomized trials:
US study (thymoquinone formula): In a placebo-controlled trial in adults with COVID-19 who were not in hospital, a thymoquinone formula shortened the median time to sustained recovery (6 days versus 8 days), but the difference was not significant. Total symptom burden fell faster with the formula (Bencheqroun et al., Pathogens, 2022) [53].
Pakistan study (black seed plus honey): In 313 adults whose COVID-19 was moderate or severe, 1 g of honey per kg and 80 mg of black seed per kg each day, given for up to 13 days, alongside standard care, shortened the time to symptom relief: 4 versus 7 days in moderate disease and 6 versus 13 days in severe disease. Deaths among severe cases were 4% versus 18.87% (Ashraf et al., Phytother Res, 2023) [54]. Because honey and black seed were given together, the effect of black seed alone is unknown.
Summary: The evidence for black seed in COVID-19 is too limited to support its use.
Hair Loss
A meta-analysis of black seed trials in skin disease covered conditions from acne to vitiligo, and hair loss was not among them [51].
Cancer (Preclinical Only)
Laboratory studies show that thymoquinone slows cancer cell growth and triggers cell death, and it has slowed colon, prostate, pancreatic and lung tumours in mice [56]. A 2016 overview recommended that black seed be developed in clinical trials, including in cancer [22].
Summary: Cancer evidence for black seed comes from laboratory and animal studies. Black seed oil should not be used as a cancer treatment.
4. Recommended Dosing
There is no established dose for black seed oil. Trials have used 200 to 4600 mg a day for 1 to 48 weeks [72].
Dosing by Form
Black seed oil (liquid or capsules):
- Prediabetes: 450 mg twice daily; trial length six months [35]
- Asthma: 500 mg twice daily for 4 weeks [42]
- Dyspepsia: 5 ml in a honey-based formulation, daily for 8 weeks [49]
- Knee osteoarthritis (oral): 2.5 mL twice a day for 6 weeks [30]
Black seed (seed), g/day:
- Asthma: 1 and 2 g/day groups, for 3 months [41]
- H. pylori (with standard treatment): 2 g a day for 8 weeks [48]; 1 g, 2 g or 3 g with omeprazole [50]
Black seed extract:
- Blood pressure in older adults: 300 mg of seed extract taken twice daily for 28 days, with no proven benefit [84]
Thymoquinone Content
Labels vary, and an analysis of six bottled oils and five oil capsules found thymoquinone from 3.08 to 809.4 mg/100 g [23]. In the highest-content oil, a dose of 4 mL a day held 30 mg of thymoquinone [23].
Based on the literature, the same authors suggested that a safe daily thymoquinone intake appears to be less than 48.6 mg for an adult [23].
Timing and Administration
Trials have usually given black seed in divided doses, such as twice daily [35, 42].
One trial mixed the oil with honey [49].
Dosing Summary Table
| Condition | Form | Daily Dose in Trials | Duration in Trials | Evidence |
|---|---|---|---|---|
| Blood sugar (prediabetes) | Oil capsules | 450 mg twice daily | six months | Trial [35] |
| Blood sugar (type 2 diabetes) | Oil or powder | Varied | Varied | Meta-analyses of 7 and 16 trials [34, 36] |
| Cholesterol | Oil or powder | Varied | Varied | Meta-analysis of 17 trials [37] |
| Blood pressure | Oil or powder (powder larger effect) | Varied | Average 8.3 weeks | Meta-analysis of 11 trials [26] |
| Weight loss | Oil or powder | Varied | Varied | Meta-analyses of 11 and 13 trials [27, 28] |
| Asthma | Oil or seed | 1 to 2 g | 4 weeks to 3 months | 2 small trials [41, 42] |
| Hashimoto's thyroiditis | Powder | Not stated | 8 weeks | Small trial, 40 people [45] |
| Knee osteoarthritis | Oil (oral or topical) | 2.5 mL by mouth twice a day | 6 weeks | Small trial, 45 people [30] |
| Acne (topical) | Hydrogel | Applied twice daily | 60 days | Trial, 60 people [29] |
5. Safety and Side Effects
General Safety Profile
A review of black seed clinical trials judged that its side effects appear not to be serious [46], and a 2018 meta-analysis reported no serious side effects [27]. In rats given the oil daily for 12 weeks, liver enzymes did not change, but platelet and white cell counts fell [67]. A 2016 overview noted that only limited non-clinical safety studies had been reported [22].
Common Side Effects
In a trial of black seed extract in older adults, reported adverse events were dyspepsia (6), nausea (3) and constipation (2) [84]:
A systematic review of knee osteoarthritis trials found that oral and topical black seed were well tolerated, with no serious adverse events [82].
Skin Reactions
Skin reactions reported with black seed include:
- Contact dermatitis: two cases have been reported (Ali and Blunden, Phytother Res, 2003) [5]
- Severe skin reactions: case reports describe a blistering drug eruption to the oil [79], DRESS syndrome (a drug reaction with rash, fever and internal organ involvement) after the oil was applied to the skin [80], and a blistering reaction resembling Stevens-Johnson syndrome after a supplement was swallowed [81]
Stevens-Johnson syndrome and DRESS can be life-threatening. For a widespread blistering rash, peeling skin or a rash with fever, stop black seed and call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.
Serious Safety Concerns
Serotonin Syndrome Risk
In rats, black seed oil raised brain serotonin and slowed its breakdown, and the authors described an antidepressant-like effect (Perveen et al., Sci Pharm, 2014) [64].
One case report described serotonin syndrome immediately after an endoscopic procedure, in which taking black seed oil beforehand appeared to have played a role (Warner et al., A A Pract, 2019) [65].
The authors advised that anaesthesia teams be aware that people taking black seed oil may develop serotonin syndrome after surgery [65]. Tell your surgeon and anaesthetist that you take it. Serotonin syndrome can be life-threatening: if it is suspected, call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.
Bleeding Risk (Thrombocytopenia)
Black seed oil has been linked to low platelet counts and bleeding:
- Case report: A 69-year-old woman who had taken black seed oil and evening primrose oil for about a month had a fall of more than 90% in her platelet count one day after surgery, with a low point of 31,000 from 410,000. The authors put this down to clots using up platelets, made worse by the two supplements (Wang et al., Cureus, 2020) [66].
- Case report: A 51-year-old man on two antiplatelet drugs and chemotherapy developed a large bleed under the skin after his black seed oil dose was raised to 2000 mg a day. Tests showed a clinically significant fall in platelets, which the authors put in the setting of his chemotherapy. The bleed resolved within 10 days, he later took 1000 mg a day without further bleeding, and the authors rated the link possible [77].
- Animal data: In rats fed the oil daily for 12 weeks, platelet counts fell significantly (Zaoui et al., Phytomedicine, 2002) [67].
- In vitro data: Thymoquinone can trigger the death of platelets in the laboratory (Towhid et al., J Cell Biochem, 2011) [68].
These findings do not show that usual doses of black seed oil cause bleeding in healthy people, but they support caution, especially around surgery or with anticoagulant or antiplatelet drugs.
Pregnancy
Its safety in pregnancy and breastfeeding has not been established; avoid it while pregnant or breastfeeding. In animal tissue, its volatile oil blocked spontaneous and oxytocin-induced contractions of rat and guinea pig uterine muscle, which suggests it may act against oxytocin [78].
Long-term Safety
Trials of black seed have lasted from 1 to 48 weeks [72]. Longer-term safety in people is unknown.
Special Populations
- Children: A 2025 review of 15 pediatric trials reported no severe adverse effects, but found too few studies to establish safety in children [83]. Ask a doctor before giving it to a child.
- Liver or kidney disease: Case reports describe acute renal failure in a person with diabetes [75], and acute kidney injury, muscle breakdown (rhabdomyolysis) and liver damage after black seed oil [74]. If you have liver or kidney disease, ask your doctor first. If you become unwell while taking it, stop it and see your doctor.
- Pre-surgical patients: Case reports describe serotonin syndrome after a procedure and a severe fall in platelets after surgery in people taking black seed oil [65, 66]. Tell your surgeon and anaesthetist that you take it, and ask when to stop it.
6. Drug Interactions
Black seed oil may interact with several classes of medications. The concerns come from its effects on blood sugar and blood pressure, laboratory and animal studies, and a few case reports.
Antidiabetic Medications
Black seed can lower fasting blood sugar and HbA1c [34, 36], so it may add to the effect of diabetes medicines. If you take metformin, sulfonylureas, insulin or other diabetes medicines, check your blood sugar more often. In prediabetes, black seed oil was statistically similar to metformin for blood sugar measures [35]. One case report describes acute renal failure associated with black seed in a person with diabetes [75].
Antihypertensive Medications
Black seed, especially as powder, can lower blood pressure [26], so it may add to the effect of blood pressure medicines. Check your blood pressure regularly if you take both.
Anticoagulant and Antiplatelet Medications
In laboratory tests, thymoquinone slowed the breakdown of warfarin by a liver enzyme, and the authors predicted that black seed oil at more than 1 g a day might change warfarin levels [76]. A man on two antiplatelet drugs and chemotherapy, with chemotherapy-related low platelets, developed a large bleed under the skin after his black seed oil dose was raised to 2000 mg a day; he later took 1000 mg a day without further bleeding, and the authors rated the link possible [77]. This could increase bleeding risk when combined with:
How much this matters at usual doses in people is unclear, but caution is warranted [66, 76, 77].
Monoamine Oxidase Inhibitors (MAOIs) and Serotonergic Drugs
Black seed oil raised brain serotonin in rats [64] and was linked to serotonin syndrome in one surgical patient [65], so it may interact with:
- MAO inhibitor antidepressants
- SSRIs and SNRIs
- Anaesthesia around surgery or procedures [65]
If you take prescription medicines, check with your doctor or pharmacist before starting.
Immunosuppressants
Laboratory and animal studies show that black seed and thymoquinone change immune responses [47]. Whether this affects immunosuppressive treatment in people is unknown. If you take prescription medicines, check with your doctor or pharmacist before starting.
Drug Interaction Summary Table
| Drug Class | Concern | Evidence | What to do |
|---|---|---|---|
| Antidiabetic drugs (metformin, insulin, sulfonylureas) | Added blood-sugar lowering | Meta-analyses [34, 36] | Check blood sugar more often |
| Blood pressure drugs | Added blood-pressure lowering | Meta-analysis [26] | Check blood pressure |
| Warfarin | Changed warfarin levels | Laboratory study [76] | Talk to your doctor first |
| Antiplatelet drugs | Bleeding | Case report [77] | Talk to your doctor first |
| MAOIs, SSRIs, SNRIs | Serotonin excess | Rat study and case report [64, 65] | Check with your doctor or pharmacist |
| Anaesthesia | Serotonin syndrome after a procedure | Case report [65] | Tell your surgeon and anaesthetist |
7. Dietary Sources
Black seed is not a nutrient found across many foods. It comes only from the seeds of Nigella sativa, eaten as whole seeds, ground powder or oil.
Culinary Use
Black seeds, called kalonji in South Asia, have long been used as food as well as medicine [1, 22].
Obtaining Therapeutic Doses from Food
Trials have used 1 to 3 g of seed a day [50] or 5 ml of oil a day [49].
Oil in Food Applications
Black seed oil is used in food products, and encapsulation has been used to improve its low oxidative stability [71].
Storage
Black seed oil has very low oxidative stability, and heat and light affect it [71]. Store it away from heat and light.
8. References
[1] Ahmad A, Husain A, Mujeeb M, et al. "A review on therapeutic potential of Nigella sativa: A miracle herb." Asian Pac J Trop Biomed. 2013;3(5):337-352. doi: 10.1016/S2221-1691(13)60075-1
[2] Kooti W, Hasanzadeh-Noohi Z, Sharafi-Ahvazi N, et al. "Phytochemistry, pharmacology, and therapeutic uses of black seed (Nigella sativa)." Chin J Nat Med. 2016;14(10):732-745. doi: 10.1016/S1875-5364(16)30088-7
[5] Ali BH, Blunden G. "Pharmacological and toxicological properties of Nigella sativa." Phytother Res. 2003;17(4):299-305. doi: 10.1002/ptr.1309
[7] Amin S, Mir SR, Kohli K, et al. "A study of the chemical composition of black cumin oil and its effect on penetration enhancement from transdermal formulations." Nat Prod Res. 2010;24(12):1151-1157. PMID: 20582810
[11] Darakhshan S, Bidmeshki Pour A, Hosseinzadeh Colagar A, Sisakhtnezhad S. "Thymoquinone and its therapeutic potentials." Pharmacol Res. 2015;95-96:138-158. doi: 10.1016/j.phrs.2015.03.011
[12] Ghosheh OA, Houdi AA, Crooks PA. "High performance liquid chromatographic analysis of the pharmacologically active quinones and related compounds in the oil of the black seed (Nigella sativa L.)." J Pharm Biomed Anal. 1999;19(5):757-762. doi: 10.1016/S0731-7085(98)00300-8
[22] Dajani EZ, Shahwan TG, Dajani NE. "Overview of the preclinical pharmacological properties of Nigella sativa (black seeds): a complementary drug with historical and clinical significance." J Physiol Pharmacol. 2016;67(6):801-817. PMID: 28195061
[23] Khaikin E, Chrubasik-Hausmann S, Kaya S, et al. "Screening of Thymoquinone Content in Commercial Nigella sativa Products to Identify a Promising and Safe Study Medication." Nutrients. 2022;14(17):3501. doi: 10.3390/nu14173501
[26] Sahebkar A, Soranna D, Liu X, et al. "A systematic review and meta-analysis of randomized controlled trials investigating the effects of supplementation with Nigella sativa (black seed) on blood pressure." J Hypertens. 2016;34(11):2127-2135. doi: 10.1097/HJH.0000000000001049
[27] Namazi N, Larijani B, Ayati MH, Abdollahi M. "The effects of Nigella sativa L. on obesity: A systematic review and meta-analysis." J Ethnopharmacol. 2018;219:173-181. doi: 10.1016/j.jep.2018.03.001
[28] Mousavi SM, Sheikhi A, Varkaneh HK, et al. "Effect of Nigella sativa supplementation on obesity indices: A systematic review and meta-analysis of randomized controlled trials." Complement Ther Med. 2018;38:48-57. doi: 10.1016/j.ctim.2018.04.003
[29] Soleymani S, Zargaran A, Farzaei MH, et al. "The effect of a hydrogel made by Nigella sativa L. on acne vulgaris: A randomized double-blind clinical trial." Phytother Res. 2020;34(11):3052-3062. doi: 10.1002/ptr.6739
[30] Amirtaheri Afshar A, Toopchizadeh V, Dolatkhah N, et al. "The efficacy of Nigella sativa L. oil on serum biomarkers of inflammation and oxidative stress and quality of life in patients with knee osteoarthritis: A parallel triple-arm double-blind randomized controlled trial." Food Sci Nutr. 2023;11(12):7910-7920. doi: 10.1002/fsn3.3708
[34] Daryabeygi-Khotbehsara R, Golzarand M, Ghaffari MP, Djafarian K. "Nigella sativa improves glucose homeostasis and serum lipids in type 2 diabetes: A systematic review and meta-analysis." Complement Ther Med. 2017;35:6-13. doi: 10.1016/j.ctim.2017.08.016
[35] Mostafa TM, Hegazy SK, Elnaidany SS, et al. "Nigella sativa as a promising intervention for metabolic and inflammatory disorders in obese prediabetic subjects: A comparative study of Nigella sativa versus both lifestyle modification and metformin." J Diabetes Complications. 2021;35(7):107947. doi: 10.1016/j.jdiacomp.2021.107947
[36] Karimi M, Pirzad S, Pourfaraji SMA, et al. "Effects of black seed (Nigella sativa L.) on cardiometabolic indices in type 2 diabetic patients: A systematic review and meta-analysis of RCTs." Complement Ther Med. 2025;90:103174. doi: 10.1016/j.ctim.2025.103174
[37] Sahebkar A, Beccuti G, Simental-Mendia LE, et al. "Nigella sativa (black seed) effects on plasma lipid concentrations in humans: A systematic review and meta-analysis of randomized placebo-controlled trials." Pharmacol Res. 2016;106:37-50. doi: 10.1016/j.phrs.2016.02.008
[38] Farhangi MA, Dehghan P, Tajmiri S. "Powdered black cumin seeds strongly improves serum lipids, atherogenic index of plasma and modulates anthropometric features in patients with Hashimoto's thyroiditis." Lipids Health Dis. 2018;17(1):59. doi: 10.1186/s12944-018-0704-x
[41] Salem AM, Bamosa AO, Qutub HO, et al. "Effect of Nigella sativa supplementation on lung function and inflammatory mediators in partly controlled asthma: a randomized controlled trial." Ann Saudi Med. 2017;37(1):64-71. doi: 10.5144/0256-4947.2017.64
[42] Koshak A, Wei L, Koshak E, et al. "Nigella sativa supplementation improves asthma control and biomarkers: A randomized, double-blind, placebo-controlled trial." Phytother Res. 2017;31(3):403-409. doi: 10.1002/ptr.5761
[44] He T, Xu X. "The influence of Nigella sativa for asthma control: A meta-analysis." Am J Emerg Med. 2020;38(3):589-593. doi: 10.1016/j.ajem.2019.11.036
[45] Farhangi MA, Dehghan P, Tajmiri S, Abbasi MM. "The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) - 1, Nesfatin-1 and anthropometric features in patients with Hashimoto's thyroiditis: a randomized controlled trial." BMC Complement Altern Med. 2016;16(1):471. doi: 10.1186/s12906-016-1432-2
[46] Tavakkoli A, Mahdian V, Razavi BM, Hosseinzadeh H. "Review on clinical trials of black seed (Nigella sativa) and its active constituent, thymoquinone." J Pharmacopuncture. 2017;20(3):179-193. doi: 10.3831/KPI.2017.20.021
[47] Majdalawieh AF, Fayyad MW. "Immunomodulatory and anti-inflammatory action of Nigella sativa and thymoquinone: A comprehensive review." Int Immunopharmacol. 2015;28(1):295-304. doi: 10.1016/j.intimp.2015.06.023
[48] Alizadeh-Naini M, Yousefnejad H, Hejazi N. "The beneficial health effects of Nigella sativa on Helicobacter pylori eradication, dyspepsia symptoms, and quality of life in infected patients: A pilot study." Phytother Res. 2020;34(6):1367-1376. doi: 10.1002/ptr.6610
[49] Mohtashami R, Huseini HF, Heydari M, et al. "Efficacy and safety of honey based formulation of Nigella sativa seed oil in functional dyspepsia: A double blind randomized controlled clinical trial." J Ethnopharmacol. 2015;175:147-152. doi: 10.1016/j.jep.2015.09.022
[50] Salem EM, Yar T, Bamosa AO, et al. "Comparative study of Nigella sativa and triple therapy in eradication of Helicobacter pylori in patients with non-ulcer dyspepsia." Saudi J Gastroenterol. 2010;16(3):207-214. doi: 10.4103/1319-3767.65201
[51] Nasiri N, Ilaghi Nezhad M, Sharififar F, et al. "The Therapeutic Effects of Nigella sativa on Skin Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials." Evid Based Complement Alternat Med. 2022;2022:7993579. doi: 10.1155/2022/7993579
[53] Bencheqroun H, Ahmed Y, Kocak M, et al. "A Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Evaluate the Safety and Efficacy of ThymoQuinone Formula (TQF) for Treating Outpatient SARS-CoV-2." Pathogens. 2022;11(5):551. doi: 10.3390/pathogens11050551
[54] Ashraf S, Ashraf S, Ashraf M, et al. "Honey and Nigella sativa against COVID-19 in Pakistan (HNS-COVID-PK): A multicenter placebo-controlled randomized clinical trial." Phytother Res. 2023;37(2):627-644. doi: 10.1002/ptr.7640
[56] Woo CC, Kumar AP, Sethi G, Tan KH. "Thymoquinone: potential cure for inflammatory disorders and cancer." Biochem Pharmacol. 2012;83(4):443-451. doi: 10.1016/j.bcp.2011.09.029
[64] Perveen T, Haider S, Zuberi NA, et al. "Increased 5-HT levels following repeated administration of Nigella sativa L. (black seed) oil produce antidepressant effects in rats." Sci Pharm. 2014;82(1):161-170. doi: 10.3797/scipharm.1304-19
[65] Warner ME, Warner PA, Sprung J, et al. "Black Seed Oil and Perioperative Serotonin Syndrome: A Case Report." A A Pract. 2019;13(11):420-422. doi: 10.1213/XAA.0000000000001096
[66] Wang X, Jiang A, Batra V. "Severe Thrombocytopenia Associated With Black Seed Oil and Evening Primrose Oil." Cureus. 2020;12(6):e8390. doi: 10.7759/cureus.8390
[67] Zaoui A, Cherrah Y, Mahassini N, et al. "Acute and chronic toxicity of Nigella sativa fixed oil." Phytomedicine. 2002;9(1):69-74. doi: 10.1078/0944-7113-00084
[68] Towhid ST, Schmidt EM, Schmid E, et al. "Thymoquinone-induced platelet apoptosis." J Cell Biochem. 2011;112(11):3112-3121. doi: 10.1002/jcb.23237
[70] Nickavar B, Mojab F, Javidnia K, Amoli MA. "Chemical composition of the fixed and volatile oils of Nigella sativa L. from Iran." Z Naturforsch C J Biosci. 2003;58(9-10):629-631. PMID: 14577620
[71] Rahim MA, Shoukat A, Khalid W, et al. "A Narrative Review on Various Oil Extraction Methods, Encapsulation Processes, Fatty Acid Profiles, Oxidative Stability, and Medicinal Properties of Black Seed (Nigella sativa)." Foods. 2022;11(18):2826. doi: 10.3390/foods11182826
[72] Jafari A, Mardani H, Faghfouri AH, et al. "Does Nigella sativa supplementation improve cardiovascular disease risk factors? A comprehensive GRADE-assessed systematic review and dose-response meta-analysis of 82 randomized controlled trials." Pharmacol Res. 2025;219:107882. doi: 10.1016/j.phrs.2025.107882
[73] Mohit M, Farrokhzad A, Faraji SN, et al. "Effect of Nigella sativa L. supplementation on inflammatory and oxidative stress indicators: A systematic review and meta-analysis of controlled clinical trials." Complement Ther Med. 2020;54:102535. doi: 10.1016/j.ctim.2020.102535
[74] Sener K, Cakir A, Yesiloglu O, et al. "Rhabdomyolysis and acute kidney injury after consumption of black seed oil." Toxicon. 2024;245:107787. doi: 10.1016/j.toxicon.2024.107787
[75] Arslan E, Sayin S, Demirbas S, et al. "A case study report of acute renal failure associated with Nigella sativa in a diabetic patient." J Integr Med. 2013;11(1):64-66. doi: 10.3736/jintegrmed2013010
[76] Wang Z, Wang Z, Wang X, et al. "Potential food-drug interaction risk of thymoquinone with warfarin." Chem Biol Interact. 2022;365:110070. doi: 10.1016/j.cbi.2022.110070
[77] Arab A, Ramezaninejad S, Salehifar E. "Extensive Subcutaneous Hematoma in a Patient Receiving Nigella sativa Oil, Dual Antiplatelet Therapy, and Oxaliplatin-Based Chemotherapy: A Case Report." Hosp Pharm. 2026. doi: 10.1177/00185787261482136
[78] Aqel M, Shaheen R. "Effects of the volatile oil of Nigella sativa seeds on the uterine smooth muscle of rat and guinea pig." J Ethnopharmacol. 1996;52(1):23-26. doi: 10.1016/0378-8741(95)01330-X
[79] Bonhomme A, Poreaux C, Jouen F, et al. "Bullous drug eruption to Nigella sativa oil: Consideration of the use of a herbal medicine - clinical report and review of the literature." J Eur Acad Dermatol Venereol. 2017;31(4):e217-e219. doi: 10.1111/jdv.13982
[80] Fargeas M, Calugareanu A, Ben-Said B. "Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome after topical use of Nigella sativa (black cumin) oil." Contact Dermatitis. 2022;87(2):203-204. doi: 10.1111/cod.14127
[81] Chu B, Kinariwalla N, Elco CP, et al. "Bullous cutaneous reaction mimicking Stevens-Johnson syndrome due to Nigella sativa supplement ingestion." JAAD Case Rep. 2026;75:339-342. doi: 10.1016/j.jdcr.2026.06.009
[82] Mousavi SE, Noori M, Marandi H, et al. "The efficacy and safety of Nigella sativa in the management of osteoarthritis: A systematic review." Health Sci Rep. 2024;7(4):e1989. doi: 10.1002/hsr2.1989
[83] Abumadini MM, Ahmad S, AlYahya W, et al. "Clinical Uses of Nigella Sativa in Pediatrics: A Systematic Review and Meta-Analysis of Randomized Controlled Trials." J Pediatr Pharmacol Ther. 2025;30(5):580-592. doi: 10.5863/JPPT-24-00044
[84] Rizka A, Setiati S, Lydia A, et al. "Effect of Nigella sativa Seed Extract for Hypertension in Elderly: a Double-blind, Randomized Controlled Trial." Acta Med Indones. 2017;49(4):307-313. PMID: 29348380
