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No active regulatory warnings
Sources: FDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
Updated: 2026-05-29 · v2.0 · Prof. G. Pkhakadze, MD, MPH, PhD📎 Cite 📄 PDF
1 Identity

Nigella Sativa (Black Seed)

Nigella sativa (Thymoquinone)
Conditionally SafeEvidence: ModerateBotanicals
Nigella sativa (black cumin, black seed, kalonji) is a traditional medicinal plant with the bioactive compound thymoquinone (TQ) as its primary pharmacological agent [1]. TQ has demonstrated anti-inflammatory (NF-κB inhibition), antioxidant, immunomodulatory, and metabolic effects across numerous preclinical and clinical studies. A meta-analysis of RCTs found N. sativa significantly reduced fasting blood glucose, HbA1c, total cholesterol, LDL, triglycerides, and blood pressure [2]. It is one of the most-studied botanicals in Islamic traditional medicine (Prophetic medicine/Tibb-e-Nabawi) [1].
2
Nigella Sativa (Black Seed)
Nigella sativa (Thymoquinone)
Conditionally SafeModerateBotanicals
Clinical verdict: N. sativa has meta-analytic support for metabolic parameters: FBG (−18 mg/dL), HbA1c (−0.45%), TC/LDL/TG reduction, and BP (−3.3/−2.8 mmHg). Effect sizes are modest but consistent across 21+ RCTs. Two clinical teaching points: (1) the warfarin interaction is real — case report of elevated INR; (2) additive hypoglycemia risk with antidiabetics. TQ content of oils varies 7-fold — standardized extracts preferred [1] [2].
RDA
Typical 500–2,000 mg oil
Target
Therapeutic range
UL
No UL
Category
Botanicals
Population dosing
🔗 Best with: Turmeric / Curcumin, Honey (Manuka or conventional), Omega-3 (EPA)✅ USP Verified, ConsumerLab Approved, Clean Label Project Certified
2 Risk self-assessment
Not applicable — N. sativa is a botanical supplement [1].
Select factors above to see your risk level
Clinical pearl for practitioners
SupplementIndex
Nigella Sativa (Black Seed)
Nigella sativa (Thymoquinone) · Conditionally Safe · Evidence: Moderate
RDA
Typical 500–2,000 mg oil
Upper limit
No UL
Evidence
Moderate
Clinical bottom line
N. sativa has meta-analytic support for metabolic parameters: FBG (−18 mg/dL), HbA1c (−0.45%), TC/LDL/TG reduction, and BP (−3.3/−2.8 mmHg). Effect sizes are modest but consistent across 21+ RCTs. Two clinical teaching points: (1) the warfarin interaction is real — case report of elevated INR; (2) additive hypoglycemia risk with antidiabetics. TQ content of oils varies 7-fold — standardized extracts preferred [1] [2].
Do not miss
⚠ Patient on warfarin adding black seed oil — antiplatelet/anticoagulant activity; monitor INR [1]
⚠ Patient on insulin/sulfonylurea adding N. sativa — additive hypoglycemia (FBG drops ~18 mg/dL) [2]
⚠ Patient expecting 'cure for every disease' — meta-analytic evidence supports metabolic benefits only [1] [2]
⚠ Patient using non-standardized oil — TQ content varies 0.5–3.5%; standardized extract preferred [1]
Pregnancy
Culinary amounts considered safe. Avoid concentrated oil/extract in pregnancy — animal data suggest uterine stimulant activity at high doses [1].
4 Dietary sources
mg thymoquinone (approximate)
mg thymoquinone (approximate)
mg thymoquinone (approximate)
mg thymoquinone (approximate)
Black seeds are used as a culinary spice in South Asian, Middle Eastern, and North African cuisines — sprinkled on bread, added to curries, and used in pickling. Culinary amounts provide modest TQ intake. Concentrated oil or extract is needed for therapeutic doses [1].
5 Lab interpreter

INR (if on warfarin)

<12 Deficient
12–20 Insufficient
20–50 Optimal
50–100 Excess
>150 Toxic
Your level:
Enter a value above
⚕ For healthcare professionals. Does not replace clinical judgment.
6 Quick facts
CategoryBotanicals
Safety levelConditionally Safe
EvidenceModerate
RDATypical 500–2,000 mg oil
Upper limit (UL)No UL
Scientific nameNigella sativa (Thymoquinone)
Plant familyRanunculaceae (buttercup family) [1]
Active compoundThymoquinone (TQ) — primary bioactive; typically 0.5–3.5% of seed oil [1]
Other activesThymohydroquinone, thymol, carvacrol, nigellone [1]
Traditional nameKalonji (South Asian), Habbatus Sauda (Arabic), Çörek otu (Turkish) [1]
Key evidenceMeta-analyses support metabolic effects: glucose, lipids, and blood pressure [2]
Dose rangeSeed: 1–3 g/day; Oil: 200–600 mg TQ/day (standardized) [1]
7 Dosage by population

Adults Moderate

See product label

Elderly Moderate

See product label
Consider reduced renal/hepatic clearance. Start at lower end of range.

Pregnancy Moderate

See guidance
Culinary amounts considered safe. Avoid concentrated oil/extract in pregnancy — animal data suggest uterine stimulant activity at high doses [1].

Pediatric Moderate

See guidance
Culinary use safe for children. No established pediatric dosing for medicinal preparations. One small RCT used black seed for allergic rhinitis in children with positive results [1].

Athletes Limited

Standard dose

Obesity Limited

Standard dose
Fat-soluble compounds may require dose adjustment in obesity.

Renal Limited

Consult specialist
Dose adjustment may be needed in renal impairment.

Vegan Moderate

Standard dose
Metabolic health (glucose/lipids): 2–3 g/day whole seed powder or 1–3 mL/day black seed oil for 8–12 weeks. Blood pressure: 2.5 mL/day oil or 500 mg/day seed extract. Immunomodulation: 40–80 mg/kg/day (research dose). Take with food. Therapeutic response requires 4–12 weeks [1] [2].
8 Form comparison
FormBioavailabilityVeganCost/day
['Black seed oil (cold-pressed)', 'common', 'Contains TQ + fixed oils. Typically 1–3 tsp/day. Variable TQ content (0.5–3.5%) depending on source [1].']StandardCheck label
['Standardized TQ extract (capsules)', 'preferred', 'Standardized to thymoquinone content. More reliable dosing than raw oil [1].']StandardCheck label
['Whole black seeds', 'traditional', 'Used in cooking and traditional preparations. Typically 1–3 g/day. Lowest bioavailability of TQ [1].']StandardCheck label
['Black seed + honey combination', 'traditional', 'Classic Prophetic medicine preparation. Traditional but not studied in RCTs as a specific combination [1].']StandardCheck label
9 Clinical evidence

Strong evidence

Metabolic effects (meta-analytic): a systematic review of 21 RCTs found N. sativa significantly reduced fasting blood glucose (WMD −17.8 mg/dL), HbA1c (WMD −0.45%), total cholesterol (WMD −15.6 mg/dL), LDL (WMD −14.1 mg/dL), and triglycerides (WMD −20.6 mg/dL) compared with placebo over 4–12 weeks [2]. HIGH

Moderate evidence

Blood pressure: meta-analysis of 11 RCTs showed SBP reduction of −3.26 mmHg and DBP −2.80 mmHg with N. sativa supplementation [2]. Anti-inflammatory: reduced CRP and TNF-α in several RCTs of metabolic syndrome patients [1]. H. pylori (adjunct): N. sativa + standard triple therapy improved eradication rate vs triple therapy alone in 2 RCTs [1]. Mastalgia: 1 RCT found topical N. sativa oil reduced cyclical breast pain [1]. MODERATE

Insufficient evidence

Cancer: extensive preclinical data (TQ induces apoptosis in cancer cell lines); no phase III human trials [1]. Asthma: traditional use; 2 small RCTs with mixed results [1]. Rheumatoid arthritis: 1 small pilot study [1]. Male fertility: 2 small RCTs showed improved sperm parameters; larger trials needed [1]. Alzheimer's: preclinical neuroprotection only [1]. LOW
10 Safety

🚩 Red flags — when to stop and refer

● Patient on warfarin adding black seed oil — monitor INR immediately [1]
● Diabetic patient on insulin reporting dizziness after starting N. sativa — check for hypoglycemia [2]
● Patient using N. sativa as sole diabetes treatment — it is an ADJUNCT, not replacement [2]

Pregnancy

Traditionally considered safe in culinary amounts. Concentrated N. sativa oil/extract should be avoided in pregnancy — animal studies suggest uterine stimulant activity at high doses. Do not exceed culinary use during pregnancy [1].

Pediatric

Culinary use safe for children. No established pediatric dosing for medicinal preparations. One small RCT used black seed for allergic rhinitis in children with positive results [1].
11 Toxicity and overdose

12 Drug interactions
Warfarin Major
Mechanism: TQ has antiplatelet and anticoagulant activity [1].
Effect: Elevated INR, increased bleeding risk. Case report documented [1].
Action: Monitor INR within 1–2 weeks of starting. Consider avoiding combination [1].
Metformin / Sulfonylureas / Insulin Moderate
Mechanism: N. sativa independently lowers FBG (meta-analysis: −17.8 mg/dL) [2].
Effect: Additive hypoglycemia [2].
Action: Monitor blood glucose. May allow dose reduction of antidiabetics under supervision [2].
13 Supplement interactions

Best combined with

Honey · 1 tsp black seed oil + 1 tbsp honey
Traditional combination (Prophetic medicine). Honey provides additional antimicrobial and prebiotic properties [1].
Turmeric / Curcumin · Standard doses of each
Complementary anti-inflammatory pathways: TQ (NF-κB) + curcumin (NF-κB via different mechanism) [1].
14 Laboratory monitoring
INR (if on warfarin) Primary
Target: Therapeutic range · Within 1–2 weeks of starting N. sativa [1].
Case report of significant INR elevation [1].
FBG / HbA1c Secondary
Target: Per diabetes management goals · Standard monitoring; more frequent initially [2].
Lipid panel Secondary
Target: Per guidelines · After 8–12 weeks supplementation [2].
15 Deficiency and prevalence
0%
[1]

Risk factors

• Not applicable — N. sativa is a botanical supplement [1].
16 Frequently asked questions
Is black seed oil a cure-all? ▼
No, despite its wide-ranging preclinical activity. The strongest clinical evidence is for metabolic parameters (glucose, lipids, BP) — all with modest effect sizes. It is a genuine metabolic adjunct, not a cure for any disease. Many traditional claims lack RCT support [1] [2].
How much thymoquinone do I need? ▼
Most positive RCTs used 1–3 mL/day black seed oil or 2–3 g/day seed powder, providing roughly 50–200 mg/day TQ. The TQ content of black seed oil varies widely (0.5–3.5%) — standardized extracts provide more reliable dosing. Cold-pressed oil from reputable sources typically has higher TQ content [1].
Is it safe with diabetes medication? ▼
Use with caution. Meta-analysis shows N. sativa reduces FBG by ~18 mg/dL. If you're on metformin, sulfonylureas, or insulin, this additive glucose-lowering could cause hypoglycemia. Monitor blood glucose more frequently when starting N. sativa [2].
Why does Islamic medicine emphasize this seed? ▼
A hadith attributed to the Prophet Muhammad states the black seed is 'a cure for every disease except death.' This cultural-religious significance has driven extensive research — N. sativa is one of the most-studied medicinal plants globally, with >1,000 published studies. The scientific evidence supports metabolic benefits but does not confirm universal therapeutic claims [1].
17 Regulatory status
United States (FDA): GRAS for food use. Available as dietary supplement. No FDA-approved health claims [1].
European Union (EFSA): Available as food ingredient and food supplement. No EFSA-authorized health claims [1].
Islamic countries: Widely used and commercially important in Saudi Arabia, Egypt, Turkey, Pakistan, and Indonesia. Available in pharmacies and traditional medicine shops [1].
India (FSSAI/Ayush): Classified as food spice (kalonji) and traditional medicine ingredient [1].
18 References
[1]Ahmad A, 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 REVIEW
[2]Daryabeygi-Khotbehsara R, et al. 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 META-ANALYSIS
[3]Sahebkar A, 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 META-ANALYSIS
[4]Tavakkoli A, et al. 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 RCT
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20 Cite this page
Vancouver
Pkhakadze G. Nigella Sativa (Black Seed) — safety profile [Internet]. Tbilisi: Public Health Institute of Georgia; 2026 [cited 2026 May 30]. Available from: https://supplement.ge/ingredients/nigella-sativa-black-seed/
APA 7th
Pkhakadze, G. (2026). Nigella Sativa (Black Seed) — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/nigella-sativa-black-seed/
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Reviewed by Prof. G. Pkhakadze, MD, MPH, PhD
Editor-in-Chief, Georgian Medical Journal · Chair, PHIG
Last reviewed: May 2026 · Next: November 2026
This entry is provided for educational and public health purposes under CC BY 4.0. Consult your healthcare provider before starting any supplement. For corrections: info@accreditation.ge.
Publisher: PHIG · Editor-in-Chief: Prof. Giorgi Pkhakadze, MD, MPH, PhD