Nigella sativa grows in Southwest Asia, the Middle East, and Southern Europe. It produces fruit with black seeds—which, while they go by the name “black seeds,” are also called black cumin, black caraway, nigella, fennel flower, and Roman coriander (1). Oil extracted from these seeds has been used in traditional medicine for over 2,000 years.
Black seed oil is considered to have a variety of properties that may benefit health, neatly summarized in Health-Promoting Activities of Nigella sativa Fixed Oil (2). Top among them: anti-inflammatory effects. The oil contains thymoquinone, a compound that “occupies vital significance” in the anti-inflammatory pathway, according to the authors. It “prevents inflammation by inhibition of the COX pathway, decreasing NF-kB translocation, and suppressing TNF-a as well as IL-5 and IL-13 mRNA expression.”
To break that down: COX stands for cyclooxygenase, an enzyme that forms compounds responsible for the inflammatory response (3). COX-1 usefully maintains the normal lining of the stomach and intestines, and is involved in kidney and platelet function; COX-2, however, is primarily found at sites of inflammation. NSAIDs, for instance, work by inhibiting both COX-1 and COX-2. COX-2-specific inhibitors have, largely, been removed from the market for increasing risk of heart attack and stroke (3). NF-kB stands for “nuclear factor kappa-light-chain-enhancer of activated B cells,” and it is found in almost all animal cell types. It is involved in cellular responses to stress, cytokines, free radicals, heavy metals, and more, and plays a role in regulating the immune response—but when mis-regulated, NF-kB is linked to inflammatory and autoimmune diseases and viral infection (4). TNF-a, or tumor necrosis factor, coordinates the inflammation process. Excess TNF—which healthy bodies block—can lead to unnecessary inflammation (5). And IL-5 and IL-13 are interleukins, regulating different portions of the immune response. So, to summarize: Thymoquinone directly inhibits inflammation along a variety of pathways.
Moreover, while there are plenty of things that work in theory, in a lab, or in rats, but not in humans, there are several human clinical trials that offer evidence that black seed oil does benefit humans. One meta-analysis, published in Journal of Food Biochemistry, comprised 10 randomized clinical trials and a total of 630 participants (6). The trials were looking at the effects of black seed oil in patients with a number of different diseases, ranging from rheumatoid arthritis to ulcerative colitis, and were measuring outcomes based on a number of different inflammatory markers, including TNF-a and hs-CRP, otherwise known as C-reactive protein, which rises in blood serum in cases of chronic inflammation. The researchers concluded that black seed supplementation significantly alters levels of inflammatory markers, stating: “[Black seed] decreased inflammatory response and oxidative stress markers, regardless of the type of disease.” Further studies are needed, with larger numbers of participants and a longer study duration. For now, the researchers say, overall, evidence supports the consumption of black seed to reduce inflammation and oxidation.
These anti-inflammatory properties aren’t all black seed oil has going for it. A few more areas in which research is promising:
Research in this area is minimal, but one study, performed in 2011, achieved statistically significant results. The researchers split 70 healthy subjects into two groups: one group received 2.5mg black seed oil twice daily, and the other received 2.5ml mineral oil twice daily (7). Fasting blood glucose, liver and renal function, and HbA1C (a form of hemoglobin that is chemically linked to a sugar, allowing health care providers to measure average blood sugar levels) were all tested at baseline and at three months. Blood samples were drawn after 12 hours of fasting. Average fasting blood glucose level in the test group at the beginning of the study was 102.4+/-20.8 mg/dl; at the end of the study, it decreased to 91/5 +/- 12.5 mg/dl. In the placebo group, on the other hand, blood sugar saw a slight increase. The difference between the two groups was statistically significant (p=0.006). HbA1c levels in the black seed oil group saw a statistically significant decrease, as well. In terms of safety, some subjects in the black seed oil group reported transient nausea; no other reactions were noted, and liver and kidney function were not adversely affected.
The researchers noted that the mechanism of action here was not clear, citing previous studies that have hypothesized that black seed oil could improve insulin sensitivity or that it could improve the action of the insulin. Another study, according to the researchers, suggested that the reduction of oxidative stress due to black seed oil’s thymoquinone content could have preserved pancreatic integrity, leading to increased insulin levels. And, of course, black seed oil has a number of bioactive constituents, all of which could be interacting with the human body in different ways. The researchers suggest that further clinical trials be performed, investigating the safety and efficacy of black seed oil in type 2 diabetics, an investigating its mechanism of action.
“The effects of Nigella sativa on plasma lipid concentrations are controversial,” according to a 2016 meta-analysis published in Pharmacological Research. To that end, the researchers conducted a review of 17 randomized controlled trials examining the effects of black seed powder and black seed oil on plasma lipid concentrations, a measure of cholesterol (8). They found a significant reduction in total cholesterol, LDL-cholesterol, and triglyceride levels, with black seed oil having a greater effect than powder. While further randomized clinical trials (RCTs) are needed, the researchers said, the results were promising.
The same researchers conducted a second meta-analysis examining the effects of black seed on blood pressure (9). They compiled 11 RCTs, including 860 hypertensive or normotensive individuals. They found that systolic and diastolic blood pressure averages both decreased after an average treatment duration of 8.3 weeks, as compared to control groups. In this case, powdered black seed showed a greater blood pressure-lowering effect than black seed oil. However, the researchers noted that more research is needed, both to strengthen existing evidence and to explore the long-term effects of black seed on blood pressure.
There is minimal research in this area, but what’s there is promising. A 2013 study published in the Journal of Ethnopharmacology split 40 elderly participants randomly into a treatment group, which received 500mg black seed twice daily for nine weeks, and a control group, which received a placebo (10). Neuropsychological tests were performed on all volunteers twice before treatment and after nine weeks, including a memory test, attention test, and a visual attention/task switching test. The test group saw significant improvement in all tests when compared to the control group, and saw no adverse reactions.
BSO and COVID-19?
Researchers have considered the use of black seed oil in cases of COVID-19. Researchers decided to look into it specifically because, in Africa, some people have consumed black seed oil in an attempt to combat COVID-19, including the Governor of Oyo State in Nigeria. The research is interesting, but preliminary: At press time, there’s only one study regarding this matter, and it was done in silico—“in silicon,” or as a computer simulation.
The researchers note in the study that there are certain components of the coronavirus that are necessary to its survival, including 3CLpro, which binds to human cell receptor ACE2 in order to produce RNA and proteins that allow the virus to proliferate (16). Thus, drugs that bind to 3CLpro and ACE2—preventing the virus from binding to human cells and proliferating—are of great interest, when it comes to helping people survive COVID-19 and decreasing severity of the disease. For instance, Remdesivir, the only drug currently approved to treat COVID-19, functions by binding to ACE2.
For the study, published in Bulletin of the National Research Centre in March 2021, researchers extracted oil from black seeds, identified the phytochemicals, and then modeled how they would interact with target proteins on the coronavirus (16). They found that caryophyllene oxide and a-bergamotene both bound to coronavirus proteins, and b-bisabolene bound to ACE2; specifically, the researchers stated that in the computer model: “The binding affinity of b-bisabolene… was almost similar to Remdesivir… on the ACE2 target.” If that were to hold true in humans, the researchers observe, b-bisabolene could prevent the virus from binding with the ACE2 protein in the human host cell, preventing infection. As noted, this study was performed using computer software, not in humans, and it hasn’t been repeated. As always, customers should discuss any supplements they take with a healthcare provider.
Hair and Skin
Black seed oil offers more benefits than just general wellness—it may be useful for skin care and hair care as well. Healthline cites a 2015 review finding benefits for psoriasis, inflammation, and acne reduction, as well as improving skin moisture and hydration (11). For hair, a 2014 study found that a mixture of coconut oil and black seed oil was effective enough in promoting hair growth to justify further study, and a 2017 study found that a hair oil containing Nigella sativa resulted in a reduction of hair fallout. To promote stronger hair growth, experts suggest applying the oil of black seed for 30 to 60 minutes on the scalp (12).
And preliminary research suggests…
There are a couple areas of research wherein scientists are beginning to explore the potential of black seed oil, but haven’t made it to human clinical trials yet. Some promising findings in animal studies:
Immune. A 2009 study looked at a rat model of allergic airway inflammation: 10 rats served as a control group; 10 rats were given an allergic reaction; and 10 rats were given an allergic reaction and treated with black seed oil (13). The findings showed that “BSO plays a vital role during the inflammatory response,” by reducing the number of inflammatory compounds including macrophages and lymphocytes and inhibiting proliferation of T-cells.
Mood. A 2014 study published in Scientia Pharmaceutica gave black seed oil to rats for four weeks (14). Levels of serotonin in the brain increased, as did levels of tryptophan, suggesting a “potential antidepressant-like effect,” according to the researchers.
A Sampling of Options
There are several available, each with their own perks. HealthAid America offers a high-dose Black Seed Oil, recommending 5g daily with a meal, or used as salad dressing; the product’s Supplement Facts label details omega-3, -6, and -9 content, as well as thymoquinone content, for a better understanding of precisely what the user is getting in each teaspoon. Bio Nutrition offers soft gels—two a day deliver 1,000mg. North American Herb & Spice offers Black Seed Oil Gelcaps, containing a proprietary blend of black seed oil along with fennel seed essential oil and wild oregano oil, for more wide-ranging support.
Black seed oil, quite clearly, has potential to support general health and wellness across a wide spectrum. As always, customers should talk to their healthcare providers about any supplement they take—black seed oil in particular may interreact with some medications (including warfarin, sold as Coumadin, and beta-blockers including metoprolol, sold as Lopressor). And while taking it for three months or fewer hasn’t been linked to any serious side effects, according to Healthline, in one study, one teaspoon of black seed oil per day for eight weeks did cause nausea and bloating in some participants (1), and there’s minimal research on larger doses and longer durations.
With its long history of traditional use, strong science support, and some intriguing preliminary research suggesting more benefits, buzz about this ancient flower continues to grow. Looking for more information and an expert’s thoughts? Listen to Steve Lankford of HealthQuestPodcast.com explore the benefits with Dr. Cass Ingram, author of The Black Seed Miracle (15). WF
- Natalie Butler, “What Is Black Seed Oil? All You Need to Know,” Posted 05/08/2020. Accessed 04/01/2021. https://www.healthline.com/nutrition/black-seed-oil
- Mahmoud Balbaa et al., “Black cumin (Nigella sativa) Chemistry, Technology, Functionality, and Applications,” Chapter 23 “Health-Promoting Activities of Nigella sativa Fixed Oil,” 361-379. 2021. https://link.springer.com/book/10.1007%2F978-3-030-48798-0
- Carol Eustice, “The Pros and Cons of Cyclooxygenase (COX),” Verywellhealth. Updated 11/22/2019. Accessed 03/17/2021. https://www.verywellhealth.com/cyclooxygenase-cox-1-and-cox-2-2552188
- “NF-kB.” Wikipedia. Last Updated 01/31/2021. Accessed 03/17/2021. https://en.wikipedia.org/wiki/NF-%CE%BAB
- Carol DerSarkissian, “How Does TNF Cause Inflammation?” WebMD. Posted 08/25/2020. Accessed 03/17/2021. https://www.webmd.com/rheumatoid-arthritis/how-does-tnf-cause-inflammation
- Somaye Fatahi et al., “The effect of nigella sativa on biomarkers of inflammation and oxidative stress: A systemic review and meta-analysis of randomized controlled trials,” Journal of Food Biochemistry. 2021. https://doi.org/10.1111/jfbc.13625
- Mohtashami et al., “Blood Glucose Lowering Effects of Nigella Sativa L. Seeds Oil in Healthy Volunteers: a Randomized, Double-Blind, Placebo-Controlled Clinical Trial,” Journal of Medicinal Plants. 10(39). 90-94(2011). http://jmp.ir/files/site1/user_files_8d9738/fallahhuseini-A-10-90-3-790fd6c.pdf
- Amirhossein Sahebkar et al., “Nigella sativa (black seed) effects on plasma lipid concentrations in humans: A systematic review and meta-analysis of randomized placebo-controlled trials,” Pharmacological Research. 106. 37-50(2016). https://www.sciencedirect.com/science/article/abs/pii/S1043661815302127
- Amirhossein Sahebkar et al., “A systemic review and meta-analysis of randomized controlled trials investigating the effects of supplementation with Nigella sativa (black seed) on blood pressure,” Journal of Hypertension. 34(11). 2127-2135(2016). https://journals.lww.com/jhypertension/Abstract/2016/11000/A_systematic_review_and_meta_analysis_of.3.aspx
- Muhammad Shahdaat Bin Sayeed et al., “The effect of Nigella sativa Linn. Seed on memory, attention, and cognition in healthy human volunteers,” Journal of Ethnopharmacology. 148(3). 780-786(2013). https://pubmed.ncbi.nlm.nih.gov/23707331/
- Scott Frothingham, “Is Black Seed Oil Good for Hair?” Posted 05/23/19. Accessed 04/05/2021. https://www.healthline.com/health/black-seed-oil-for-hair
- Briana Mercado, “The Many Benefits of Black Seed Oil,” WholeFoods Magazine. Posted 04/21/2017. Accessed 04/06/2021. https://wholefoodsmagazine.com/blog/many-benefits-black-seed-oil/
- Muhammad Shahzad et al., “Black seed oil ameliorates allergic airway inflammation by inhibiting T-cell proliferation in rats,” Pulmonary Pharmacology & Therapeutics. 22(1). 37-43(2009). https://www.sciencedirect.com/science/article/abs/pii/S1094553908001223
- Tahira Perveen et al., “Increased 5-HT Levels Following Repeated Administration of Nigella sativa (Black Seed) Oil Produce Antidepressant Effects in Rats,” Scientia Pharmaceutica. 82(1). 161-170(2014). https://www.mdpi.com/2218-0532/82/1/161
- Steve Lankford, “Dr. Cass Ingram Discusses the Benefits of Black Seed,” WholeFoods Magazine. Posted 08/17/2020. Accessed 04/06/2021. https://wholefoodsmagazine.com/multimedia/podcast/dr-cass-ingram-discusses-the-benefits-of-black-seed/
- Chidi Edbert Duru, Ijeoma akunna Duru, Abayomi Emmanuel Adegboyega, “In silico identification of compounds from Nigella sativa seed oil as potential inhibitors of SARs-CoV-2 targets,” Bulletin of the National Research Centre. 45. 2021. https://link.springer.com/article/10.1186/s42269-021-00517-x