Black Seed (Nigella) (Nigella sativa): Uses, Evidence and Safety
Black seed (Nigella sativa): what the seed is, how it has been used traditionally, what blood pressure and blood sugar trials found, and the medicine, skin and pregnancy cautions.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
What is Black seed good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Blood pressure (small average fall)
Preliminary or mixedPooled trials found black seed lowered blood pressure by about 3 mmHg on average compared with control groups. Results varied widely between trials.
Supplements: Small and inconsistent effect; not a substitute for blood pressure treatment. Ask about blood pressure medicines.
Blood sugar (people with metabolic disease)
Preliminary or mixedIn a review of 31 trials, fasting glucose and HbA1c were lower on average with black seed, but there was no clear effect on insulin resistance.
Supplements: Preliminary; not a replacement for diabetes care. Could add to diabetes medicines.
Weight and heart risk markers
Preliminary or mixedReviews of short trials report small changes in weight, BMI and other heart risk markers. They measured markers, not heart attacks or strokes.
Supplements: Preliminary; trials were short and varied in product and quality.
Knee pain (topical oil versus oral seed)
Not enough evidenceMSK reports that topical oil eased knee osteoarthritis pain in small trials, while oral seed powder did not.
Supplements: Insufficient evidence; oral seed powder did not relieve knee pain.
Asthma, allergy, arthritis, fatty liver and digestion
Not enough evidenceMSK says small trials suggest possible benefit in several conditions, but the studies are small and larger ones are needed.
Supplements: Insufficient: unverified small trials.
Immune and antioxidant effects in the lab
Lab or animal research onlyLab and animal studies describe immune-modulating, antioxidant and liver-protective effects. These findings have not been shown to help people.
Supplements: No human benefit shown from lab findings.
Cancer (not shown in humans)
Lab or animal research onlyMSK states black seed has not been shown to treat cancer in humans. Findings come from lab and animal work.
Supplements: Not shown to treat cancer in humans.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (5)
- Blood Pressure SupportPreliminary or mixed
Pooled trials found average blood pressure falls of about 3 mmHg (systolic) and 3 mmHg (diastolic), but results varied a lot between trials and one database calls the evidence conflicting. Not a replacement for blood pressure treatment.
- Blood Sugar BalancePreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose and HbA1c, but study quality varied and the authors urge caution. Not a replacement for diabetes care.
- Heart HealthPreliminary or mixed
An 82-trial review calls black seed a promising add-on for heart risk factors, but the trials were short and measured risk markers, not heart attacks or strokes.
- Metabolic HealthPreliminary or mixed
Reviews of small, short trials report small changes in weight, blood pressure and blood sugar in people with metabolic disease. They found no significant effect on insulin resistance or waist size.
- Weight ManagementPreliminary or mixed
In people with metabolic disease, pooled trials found an average weight change of about 1.6 kg lower than comparison groups. Study quality varied.
Body systems (6)
- Blood Sugar SupportPreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose and HbA1c, but study quality varied and the authors urge caution. Not a replacement for diabetes care.
- Cardiovascular SystemPreliminary or mixed
Pooled trials found average blood pressure falls of about 3 mmHg (systolic) and 3 mmHg (diastolic), but results varied a lot between trials and one database calls the evidence conflicting. Not a replacement for blood pressure treatment.
- Heart & CirculationPreliminary or mixed
Pooled trials found average blood pressure falls of about 3 mmHg (systolic) and 3 mmHg (diastolic), but results varied a lot between trials and one database calls the evidence conflicting. Not a replacement for blood pressure treatment.
- Integumentary SystemDocumented risk
Pure black seed oil on the skin has caused allergic reactions and contact dermatitis, including one severe reaction needing corticosteroids.
- Metabolism & WeightPreliminary or mixed
Small average changes in weight and blood sugar were reported in trials of people with metabolic disease; quality varied.
- Reproductive SystemDocumented risk
In pregnant mice a seed extract reduced litter size and delayed some reflexes in pups. No human pregnancy data were found, so caution is advised.
Body parts (2)
- SkinDocumented risk
Pure black seed oil on the skin has caused allergic reactions and contact dermatitis in reports.
- Blood VesselsPreliminary or mixed
Pooled trials found average blood pressure falls of about 3 mmHg (systolic) and 3 mmHg (diastolic), but results varied a lot between trials and one database calls the evidence conflicting. Not a replacement for blood pressure treatment.
Functional actions (5)
- Blood Sugar RegulationPreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose and HbA1c, but study quality varied and the authors urge caution. Not a replacement for diabetes care.
- AntioxidantLab or animal research only
Lab and animal studies describe antioxidant effects. This has not been shown to benefit people.
- Cardiovascular SupportPreliminary or mixed
Pooled trials found average blood pressure falls of about 3 mmHg (systolic) and 3 mmHg (diastolic), but results varied a lot between trials and one database calls the evidence conflicting. Not a replacement for blood pressure treatment.
- Immune ModulationLab or animal research only
Lab and animal studies describe immune-modulating effects. This has not been shown to benefit people.
- Liver SupportLab or animal research only
Lab and animal studies describe liver-protective effects. A few small human trials in fatty liver disease exist but are not enough to confirm benefit.
Root causes (2)
- Blood Sugar ImbalancePreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose and HbA1c, but study quality varied and the authors urge caution. Not a replacement for diabetes care.
- Medication Side EffectsDocumented risk
Black seed may inhibit the liver enzymes CYP2D6 and CYP3A4 and could change levels of medicines cleared by them; thymoquinone inhibited warfarin activity in a lab study. Whether this matters in people is not known. Ask a pharmacist.
Biomarkers (2)
- Blood GlucosePreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose (about 18.6 mg/dL). Quality varied; authors urge caution.
- HbA1cPreliminary or mixed
Pooled trials in people with metabolic disease found HbA1c about 0.56 lower. Quality varied; authors urge caution.
Conditions & symptoms (3)
- Contact DermatitisDocumented risk
Pure black seed oil on the skin has caused contact dermatitis in reports.
- Diabetes Mellitus, Non-Insulin-DependentPreliminary or mixed
Pooled trials in people with metabolic disease found lower fasting glucose and HbA1c; reviews of this condition specifically were not read. Authors urge caution.
- Essential HypertensionPreliminary or mixed
Pooled trials found small average falls in blood pressure (about 3 mmHg), with large differences between trials; MSK calls blood pressure data conflicting. Not a replacement for treatment.
Documented risks and interactions (4)
- Medicine interactions (liver enzymes, warfarin). Black seed may inhibit the liver enzymes CYP2D6 and CYP3A4 and change levels of medicines cleared by them. Thymoquinone inhibited warfarin activity in lab work.
- Skin reactions to the oil. Pure oil on the skin has caused allergic reactions and contact dermatitis. One report describes a severe reaction (DRESS) needing corticosteroids.
- Pregnancy caution. In pregnant mice a seed extract reduced litter size, lengthened gestation and delayed some reflexes in pups. No human pregnancy data were found.
- Liver and kidney effects at high doses. High doses caused liver and kidney damage in rats. Human data are lacking; a 12-week animal study of the oil showed no liver enzyme change.
Ask a pharmacist before combining black seed with regular medicines. A cancer-center herb database says Nigella sativa may affect how the body handles drugs cleared by certain liver enzymes, and that thymoquinone (a major constituent) inhibited warfarin activity in lab work. Its clinical relevance is not known. [1] Trials also found small drops in blood pressure and blood sugar, so ask about blood pressure and diabetes medicines too. [2][3]
What black seed is
Black seed, also called black cumin, is the seed of Nigella sativa. It is an accepted species in the buttercup family (Ranunculaceae). [4] It is a flowering plant found across India, Arabia and Europe, and the seeds are used in cooking. [1] This page covers the seed and its powder. Pressed oil and capsules are different products; see black seed oil for the oil.Traditional use (not proof)
In traditional medicine the seeds have been used to reduce inflammation, and to treat infections and cancer. [1] The wider traditions around the seed are covered at Black seed in Islamic and other traditions. Traditional use is a record of what people have done. It does not show that a use works.What research shows
Human research is mostly small trials of black seed powder, oil or extracts, pooled into reviews. Results below describe those reviews, not a plant used at home.| Use | What the source found | Strength of evidence |
|---|---|---|
| Blood pressure | A 2016 review of 11 trials (860 people) found average falls of about 3.3 mmHg (systolic) and 2.8 mmHg (diastolic) versus comparison groups. [5] A 2023 update reported a fall of about 3.1 mmHg (systolic). [2] | Promising but limited. The 2023 authors call earlier findings controversial, and one database calls antihypertensive data conflicting. [2][1] |
| Form matters for blood pressure | Powder and oil lowered pressure differently, in favor of powder. [5] | Limited |
| Blood sugar (people with metabolic disease) | A review of 31 trials (2,145 people) found lower fasting glucose (about 18.6 mg/dL) and HbA1c (about 0.56). [3] | Promising but limited. The authors urge caution because study quality and outcomes varied. [3] |
| Insulin resistance, waist size | No significant effect in that review. [3] | No clear benefit found |
| Broader heart and metabolic markers | An 82-trial review (5,026 people, 1 to 48 weeks, amounts from 200 to 4,600 mg/day in the trials) called it a promising adjunct. [6] | Promising but limited; short trials, surrogate markers |
| Knee osteoarthritis | A database summarizes topical and oral use as relieving knee pain in small trials, but oral seed powder as not. [1] | Insufficient evidence |
| Cancer | Has not been shown to treat cancer in humans; animal findings only. [1] | Preclinical |
These trial amounts are not advice. A clinician or pharmacist decides what, if anything, is right for a person. Larger studies are still needed. [1]
Proper evidence not found: we did not read human trial data on long-term safety, children, or use during pregnancy. We looked at the MSK herb database, PubMed reviews on blood pressure and blood sugar, and PubMed searches for safety and pregnancy.
Safety
- Medicines: Nigella sativa inhibits the liver enzymes CYP2D6 and CYP3A4 and can affect levels of drugs cleared by them. [1] It is not known whether this matters in people. See how interactions work. Because trials found lower blood pressure and blood sugar, ask whether black seed could add to those medicines. [2][3]
- Skin: Pure N. sativa oil on the skin caused allergic reactions, and contact dermatitis has been reported. One report describes a 28-year-old woman who needed corticosteroids after applying the oil. [1]
- Liver and kidney: High doses caused liver and kidney damage in rats; human data are lacking. [1] People with liver or kidney disease should ask a clinician first. See liver safety.
- Pregnancy: In one mouse study, black seed extract during pregnancy reduced litter size, lengthened gestation and delayed some reflexes in pups. The authors urged caution. [7] Mouse results may not apply to people, and we found no human pregnancy data. See pregnancy and breastfeeding. Breastfeeding and children: not described in the sources we read.
- Surgery: Tell the surgical team about any herb. See supplements before surgery.
Quality
Seed, powder, oil and capsules differ, and a result for one does not carry to another. Amounts and contents vary by product. How testing programs work is explained at quality testing and certifications.Related pages
Herb safety essentials, fenugreek and herbs studied for blood sugar.Frequently asked questions
Is black seed the same as black cumin?
Yes, both names are used for the seed of Nigella sativa. [1]
Does black seed lower blood pressure?
Pooled trials found small average drops of about 3 mmHg, but one 2023 paper calls the findings controversial, and quality varies. [2]
Can black seed affect my medicines?
It may. It inhibits CYP2D6 and CYP3A4 and thymoquinone inhibited warfarin activity in lab work; relevance in people is not known. Ask a pharmacist. [1]
Is black seed safe in pregnancy?
We found no human data. A mouse study showed reduced litter size and delayed reflexes, so caution is advised. Ask a clinician. [7]
Can black seed oil hurt the skin?
Pure oil on skin caused allergic reactions in reports, so a skin test and clinician advice make sense. [1]
References
- Memorial Sloan Kettering Cancer Center (US), Nigella sativa, About Herbs database, last updated August 2023. Read 2026-10-23.
- Antihypertensive effects of Nigella sativa supplementation: an updated systematic review and meta-analysis. Phytotherapy Research, 2023. Read 2026-10-23.
- Nigella sativa supplementation and cardiometabolic health in patients with metabolic diseases: GRADE-assessed systematic review and meta-analysis. Endocrinology, Diabetes & Metabolism, 2026. Read 2026-10-23.
- GBIF Backbone Taxonomy, Nigella sativa. Read 2026-10-23.
- Sahebkar A, et al. Nigella sativa (black seed) and blood pressure: systematic review and meta-analysis of randomized controlled trials. Journal of Hypertension, 2016. Read 2026-10-23.
- Nigella sativa and cardiovascular risk factors: GRADE-assessed systematic review and dose-response meta-analysis of 82 randomized controlled trials. Pharmacological Research, 2025. Read 2026-10-23.
- Effect of Nigella sativa consumption during pregnancy on fertility, morphology and behaviors of mouse offspring. Birth Defects Research, 2025 (mice, not humans). Read 2026-10-23.