Oil
    Moderate Evidence

    Black Seed Oil

    Nigella sativa

    TL;DR

    Black seed oil, standardised for thymoquinone, has meta-analytic support for modest reductions in blood pressure, LDL cholesterol, HbA1c and body weight at 1-3 g/day. Effect sizes are small but the pattern across metabolic markers is unusually consistent for a botanical.

    Ideal For

    • Clustered metabolic risk factors
    • Mildly elevated blood pressure
    • Prediabetes and modestly raised HbA1c
    • Allergic rhinitis, as a secondary use

    Avoid If

    • Pregnancy
    • Taking warfarin or antiplatelet drugs
    • On antihypertensives or insulin without monitoring
    • Scheduled surgery within two weeks

    Frequently Asked Questions

    Overview

    Black seed is one of the more interesting botanicals in metabolic medicine because its trial signal appears across several distinct markers rather than in one narrow domain. Meta-analyses report reductions in fasting glucose and HbA1c, in total and LDL cholesterol, in systolic and diastolic blood pressure, and modest reductions in weight and waist circumference. Individually, each effect is small — an HbA1c reduction of a few tenths of a percentage point, blood pressure down a few millimetres of mercury. Collectively, in someone with clustered metabolic risk, they are not trivial. The active constituent is thymoquinone, and here is the practical catch: cold-pressed culinary oils vary widely in thymoquinone content, from under 0.2% to over 1%, and most trials used either standardised oil or seed powder at doses substantially higher than a culinary teaspoon. There is also a small literature in allergic rhinitis and asthma consistent with the anti-inflammatory mechanism.

    How It Works

    • Thymoquinone activates Nrf2 antioxidant defences
    • Inhibits NF-kB, lowering TNF-alpha and IL-6
    • Improves insulin signalling and AMPK activity
    • Supports nitric oxide availability, aiding vasodilation

    Quick Facts

    • Small effects across several metabolic markers at once
    • Thymoquinone content varies widely between products
    • 1-3 g/day is the studied range, well above culinary use
    • Additive with blood pressure and glucose medication

    Benefits & Outcomes

    No linked outcomes yet. Research is ongoing.

    Health Concerns Addressed

    High Cholesterol (Dyslipidemia)

    condition
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    A genuine but modest lipid effect. Reasonable as an adjunct to diet; not a replacement for statin therapy where that is indicated.

    Supporting Research
    11 studies

    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

    Score: 9/10
    2025
    meta_analysis
    n=5026

    Jafari A, Mardani H, Faghfouri AH +2 more

    N. sativa supplementation significantly improved body fat percentage (BF%), body mass index (BMI), skeletal muscle mass (SMM), waist circumference (WC), weight, waist-to-hip ratio (WHR), diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP), fasting blood sugar (FBS), hemoglobin A1c (HbA1c)

    View source

    Antihypertensive effects of Nigella sativa supplementation: An updated systematic review and meta-analysis of randomized controlled trials

    Score: 7/10
    2023
    meta_analysis

    Kavyani Z, Musazadeh V, Safaei E +1 more

    Nigella sativa supplementation significantly reduced systolic and diastolic blood pressure compared with control, with larger effects in trials of 8 weeks or longer.

    View source

    Effects of Nigella sativa supplementation on lipid profiles in adults: An updated systematic review and meta-analysis of randomized controlled trials

    Score: 8/10
    2024
    meta_analysis
    n=2278

    Rounagh M, Musazadeh V, Hosseininejad-Mohebati A +2 more

    N. sativa supplementation significantly reduced total cholesterol (TC) (SMD: -1.78; 95% CI: -2.20, -1.37, p < 0.001), triglycerides (TG) (SMD: -1.2725) and low-density lipoprotein cholesterol (LDL-C) (SMD: -2.45)

    View source

    Effects of Nigella sativa on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials

    Score: 7/10
    2020
    meta_analysis

    Hallajzadeh J, Milajerdi A, Mobini M +1 more

    Nigella sativa significantly reduced fasting glucose, HbA1c, total cholesterol and LDL cholesterol, while effects on HDL and inflammatory markers were inconsistent.

    View source

    The effect of Nigella sativa supplementation on glycemic status in adults: An updated systematic review and meta-analysis of randomized controlled trials

    Score: 8/10
    2024
    meta_analysis

    Shirvani S, Falahatzadeh M, Oveili E +2 more

    N. sativa supplementation significantly reduced FBS (SMD: -1.71) and HA1c levels (SMD: -2.16) but not effect on insulin (P = 0.353), and HOMA-IR (p=0.229)

    View source

    A systematic review and meta-analysis of randomized controlled trials investigating the effects of supplementation with Nigella sativa (black seed) on blood pressure

    Score: 7/10
    2016
    meta_analysis

    Sahebkar A, Beccuti G, Simental-Mendia LE +2 more

    Short-term Nigella sativa supplementation reduced systolic blood pressure by about 3.3 mmHg and diastolic by about 2.8 mmHg versus control.

    View source

    Effect of Nigella sativa supplementation on obesity indices: A systematic review and meta-analysis of randomized controlled trials

    Score: 7/10
    2018
    meta_analysis
    n=875

    Mousavi SM, Sheikhi A, Varkaneh HK +2 more

    NS supplementation significantly reduced BW (Weighted Mean Differences (WMD): -1.76 kg, 95% CI: -3.34 to -0.17)

    View source

    Effect of Nigella sativa in the treatment of nonalcoholic fatty liver disease: A systematic review and meta-analysis of randomized controlled trials

    Score: 7/10
    2021
    meta_analysis
    n=358

    Tang G, Zhang L, Tao J +1 more

    Although NS has no beneficial effect on the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL), triglyceride (TG), insulin, and tumor necrosis factor α (TNF-α), its supplementation did improve the levels of alanine transaminase (ALT), aspartate transaminase (AST), fasting blood sugar (FBS), high-density lipoprotein cholesterol (HDL), high-sensitivity C reactive protein (hs-CRP), and grade of fatty liver

    View source

    The influence of Nigella sativa for asthma control: A meta-analysis

    Score: 6/10
    2020
    meta_analysis

    He T, Xu X

    Nigella sativa supplementation is associated with increased ACT scores (Std. MD = 0.50; 95% CI = 0.11 to 0.88; P = 0.01), FEV1 (Std. MD = 1.84), but demonstrates no obvious impact on PEF (P = 0.17), IL-4 (P = 0.50), or IFN-γ (P = 0.16)

    View source

    Nigella sativa Supplementation Improves Asthma Control and Biomarkers: A Randomized, Double-Blind, Placebo-Controlled Trial

    Score: 6/10
    2017
    rct
    n=80

    Koshak A, Wei L, Koshak E +2 more

    NSO capsules 500 mg twice daily for 4 weeks were used as a supplementary treatment in a randomized, double-blind, placebo-controlled trial in asthmatics

    View source

    A randomized, double-blind, placebo-controlled study to evaluate the benefits of a standardized Nigella sativa oil containing 5% thymoquinone in reducing the symptoms of seasonal allergy

    Score: 5/10
    2024
    rct
    n=65

    Majeed A, Majeed S, Parameswarappa AK +2 more

    A significant reduction in Total Nasal Symptom Score and Total Ocular Symptoms Score was observed in the NSO group compared to the placebo

    View source

    Safety Information

    Potential Side Effects

    Usually mild: gastrointestinal upset, nausea and reflux. Contact dermatitis with topical use. Rare hepatotoxicity reports at very high doses.

    Contraindications

    Avoid in pregnancy — animal data suggest uterine effects. Monitor closely if combining with glucose-lowering or blood pressure medication, since effects are additive.

    Drug Interactions

    • Antihypertensives — additive blood pressure lowering
    • Insulin and sulfonylureas — additive hypoglycaemia risk
    • Warfarin — possible increased bleeding tendency
    • CYP3A4 substrates — thymoquinone inhibits several CYP enzymes

    Pregnancy & Breastfeeding

    Pregnancy: likely_unsafe

    Breastfeeding: insufficient_data

    Dosage Guidelines

    Dosage Used in Studies

    1000-3000 mg

    Best Time to Take

    Once or twice daily with meals

    Best Form

    Oil standardised to thymoquinone content, or ground seed at 1-3 g/day

    Bioavailability

    Thymoquinone is lipophilic with modest oral bioavailability; taking with fat improves absorption considerably.

    Forms Compared

    Standardised oil

    Ground seed

    Thymoquinone-enriched capsule

    Food & Timing

    Take with food — thymoquinone is lipophilic and absorption improves with dietary fat.

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.