Herb ·Emerging evidence ·Reviewed May 2026
Traditional Middle Eastern remedy with broad immune-modulatory and anti-inflammatory effects.
The bottom line
Evidence rating emerging. Most-documented uses: immune modulation, anti-inflammatory, blood sugar support. 21 sources indexed (2013–2024), with 6 interaction records on file.
Core mechanism
Thymoquinone is the primary active compound, inhibiting NF-κB, COX-2, and 5-LOX. Modulates T-helper cell balance, supports natural killer cell activity, and has hepatoprotective effects.18,17
Dosing protocol
Thymoquinone content varies sharply; look for standardized extracts.16
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Cold-Pressed Black Seed Oil.
Assumes 500-1,000 mg softgel or equivalent oil serving. Vendor basis: iHerb, Vitacost, Life Extension, and Amazon marketplace; thymoquinone-standardized extracts set premium. Updated 2026-05-28.
How much you'd eat to match a supplemental dose.
The oil or seeds are the food source; thymoquinone content varies by seed source and oil processing.
What to test, the optimal window inside the conventional range, and how long a response takes.
Nigella sativa oil (1 to 3 g per day) and thymoquinone-standardized extracts lower LDL, triglycerides, and HbA1c modestly in meta-analyses.16,17
Pair with HbA1c and full lipid panel. Thymoquinone content varies widely; look for standardized extracts.
Black seed oil (Nigella sativa) may modestly lower HbA1c, with effects that are typically small, dose-dependent, and most apparent when baseline glucose control is impaired.1,2
Fasting is not required since HbA1c reflects roughly 2 to 3 months of average glucose. Because it tracks red cell lifespan, retest no sooner than 3 months and interpret cautiously if anemia or recent blood loss is present.
Black seed oil (Nigella sativa) may modestly lower triglycerides, with effects that are typically small, dose-dependent, and clearest when triglycerides are elevated at baseline.1,2
Requires a 9 to 12 hour fast since triglycerides rise sharply after meals. Avoid alcohol for 2 to 3 days before testing and keep recent diet and activity consistent, as both strongly confound results.
Both lower blood glucose, so combined use can produce additive hypoglycemic effects, particularly in people also taking diabetes medications.
Recommendation: Monitor blood glucose more closely when combining. Watch for symptoms of hypoglycemia (shakiness, sweating, confusion) and coordinate with a clinician if on antidiabetic drugs.
Both can modestly lower blood pressure and affect platelet function, so combining them may produce additive reductions in blood pressure and a small additive antiplatelet effect.
Recommendation: Generally well tolerated, but monitor blood pressure if hypotension-prone and watch for easy bruising or bleeding, especially around surgery or with anticoagulants.
Both are anti-inflammatory and antioxidant agents that have shown complementary metabolic benefits when studied together, including improved glycemic and lipid markers.
Recommendation: Reasonable combination for anti-inflammatory and metabolic support. No special timing required; taking both with a fat-containing meal aids absorption.
Both supplements are well-documented oral hypoglycemics in human trials. Taken concurrently, especially alongside antidiabetic medication (metformin, sulfonylureas, insulin), they can produce a larger-than-expected drop in blood glucose. The combination is not dangerous in healthy normoglycemic users, but in people actively managing diabetes or prediabetes it raises a real risk of additive hypoglycemia.
Recommendation: If you take both, monitor blood glucose more closely for the first 2 to 3 weeks, particularly if you are also on glucose-lowering medication. Typical doses studied are Black Seed Oil around 1 to 2.5 g/day and Fenugreek 5 to 10 g/day of seed (or standardized extract per label). Watch for hypoglycemia symptoms (shakiness, sweating, lightheadedness). Discuss with your prescriber before combining if you use insulin or a sulfonylurea, as medication doses may need adjustment. No specific timing separation is required.
Two supplements with reproducible antihypertensive effects in human trials. Combined, the blood-pressure reduction can be additive, which is helpful for someone targeting blood pressure but can cause hypotension (dizziness, lightheadedness on standing) in people already at or below target, or those on antihypertensive medication. The shared mild antiplatelet effect also modestly raises bleeding risk, relevant around surgery or with anticoagulants.
Recommendation: This pairing can be used intentionally for cardiovascular support, but monitor blood pressure during the first few weeks and stand up slowly to check for orthostatic symptoms. Typical studied doses: Black Seed Oil 0.5 to 2.5 g/day (standardized products around 3% thymoquinone) and aged or standardized garlic extract 600 to 1200 mg/day. If you are on antihypertensive drugs, coordinate with your prescriber, as the combination may lower the medication requirement. Because of the combined antiplatelet effect, pause both at least 1 to 2 weeks before any scheduled surgery and avoid combining with prescription anticoagulants without medical advice. No daily timing separation needed.
Thymoquinone, the main bioactive in black seed oil (Nigella sativa), is a competitive inhibitor of CYP2C9-mediated warfarin 7-hydroxylation. Pharmacokinetic modeling predicts that thymoquinone intakes above ~18 mg/day, or black seed oil above ~1 g/day, can meaningfully reduce warfarin clearance and raise INR.
Recommendation: Avoid black seed oil supplements while on warfarin. Culinary use of small amounts of seeds is unlikely to matter. If you take a supplement, tell your anticoagulation clinic and ask for an INR check within 1-2 weeks.
Numbered references. Citations throughout the page link here.
Meta-analysis showed Nigella sativa supplementation significantly reduced fasting blood glucose, HbA1c, and HOMA-IR in type 2 diabetes patients.
Meta-analysis of RCTs demonstrated that Nigella sativa supplementation significantly reduced both systolic and diastolic blood pressure.
Ali M, Tantawi M, Kamel AH et al.. Endothelial Function Responses to Nigella sativa (Black Seed) Supplementation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Cureus. 2024
Elhariri S, Burud I, Zulaimy NA et al.. Systematic Review of Randomized Controlled Trials in Uses of Nigella Sativa (Black Seed) in Metabolic Syndrome. West African journal of medicine. 2024
Mousavi SE, Noori M, Marandi H et al.. The efficacy and safety of Nigella sativa in the management of osteoarthritis: A systematic review. Health science reports. 2024
He Y, Hu X, Chang L et al.. Meta-analysis of randomized controlled trials assessing the efficacy of nigella sativa supplementation for allergic rhinitis treatment. Frontiers in pharmacology. 2024
N. sativa consumption associated with improvements in blood pressure, lipid profile, inflammatory markers, oxidative stress, and glycemic control across multiple meta-analyses.
Twenty RCTs (1086 participants) showed N. sativa significantly reduced inflammatory and oxidative stress biomarkers.
Meta-analysis found Nigella sativa supplementation significantly reduced CRP, TNF-alpha, and IL-6 levels, supporting its anti-inflammatory properties.
Kavyani Z, Musazadeh V, Safaei E et al.. Antihypertensive effects of Nigella sativa supplementation: An updated systematic review and meta-analysis of randomized controlled trials. Phytotherapy research : PTR. 2023
N. sativa supplementation reduced systolic BP by -3.26 mmHg and diastolic BP by -2.80 mmHg compared to control groups.
TC reduced 15.6 mg/dL, LDL reduced 14.1 mg/dL, TG reduced 20.6 mg/dL
Extensive studies show N. sativa safe at therapeutic doses; adverse effects include GI symptoms at higher doses; subchronic NOAEL for thymoquinone is 5 mg/kg in rats.
Numerous clinical and animal studies demonstrate antidiabetic efficacy of black seeds and thymoquinone, though large-sample high-quality RCTs are needed.
Thymoquinone is the primary active compound with demonstrated effects on inflammatory/autoimmune disorders, metabolic syndrome, and cancer in clinical trials.
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