People traditionally use black seed to improve inflammation, allergies, immune defense, and weight loss. It can be taken as a spice, extract, or oil. Despite being touted as a “miraculous herb,” many of its traditional uses have not been validated by proper scientific studies. Read on to learn more about the purported benefits and risks of black seed.
What is Black Seed?
Nigella sativa, commonly known as black seed, black caraway, and kalonji is a flowering plant native to South Asia. Its fruit is large and contains numerous small black seeds .
Black seed is also sometimes called black cumin (or black cumin seed), although this can be misleading. Cumin or Cuminum cyminum is a spice with few overlapping benefits that belongs to an entirely different plant family than black seed.
In this article, any mention of black seed or black cumin refers specifically to Nigella sativa.
Nigella sativa raw seeds, seed oil, or seed extract have been traditionally used alone or in combination with other ingredients for various health conditions, such as eczema, cough, headache, diabetes, asthma, infections, and high blood pressure .
Few of the claims that come from its traditional reputation in various cultures have been researched, while most others lack scientific evidence. Most of the research on black seed so far has only been carried out in cells or animals .
Additionally, black seed supplements have not been approved by the FDA for medical use. In general, dietary supplements lack solid clinical research. Regulations set manufacturing standards for supplements but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
The main and most researched active ingredient in black cumin seed oil is thymoquinone. Thymoquinone has been studied for protecting the liver, reducing inflammation, and as an antioxidant. It’s also being examined in cancer research. Additionally, the seeds contain alpha-Hederin, another ingredient that’s being studied in cancer cells [2, 3].
Black seeds also contain :
- Various vitamins and minerals, such as copper, phosphorus, zinc, iron, and carotene (provitamin A).
- Fatty acids, which make about 30% of the seeds. These are mostly unsaturated fatty acids, including linoleic acid and oleic acid, and some saturated fatty acids.
Black seeds have been used in Middle Eastern, Asian, and European folk medicine as a natural remedy for a wide range of diseases for over 2000 years .
In Islamic cultures, its use has a strong religious background. Islamic literature claims that regular use of black seed is “a cure for every disease (except death),” which earned this spice the Arabic approbation “The Blessed Seed.” Black seed is also considered an important remedy in Ayurveda .
Black seed has a specific bitter taste and smell and is often added to confectionery and liquors. The oil can be used to add flavor to various dishes, but people also traditionally apply it on the skin as an alleged painkiller and antiseptic.
Despite its cultural significance, the traditional uses and purported health benefits of black seed remain unproven.
- May reduce allergies
- Considered an antihistamine
- Weak evidence against bacterial, fungal, and viral, and parasitic infections
- Limited evidence for weight loss benefits, reducing inflammation and pain
- May support cardiovascular health
- Clinical studies are lacking
- Traditional uses are unproven
- May lower blood sugar and interact with anti-diabetes medication
- Not safe to use during pregnancy
- Proper dosage and long-term safety unknown due to the lack of data
Purported Health Benefits of Black Seed Oil
Possibly Effective for:
A boiled extract of the seeds improved asthmatic symptoms in one study (15 mL/kg of 0.1 g% boiled extract daily) of 29 asthmatic patients. It reduced the frequency of asthma symptoms, wheezing, and improved lung function over 3 months. The patients who took black cumin seed extract also had a reduced need for additional medications and inhalers .
Another placebo-controlled study of 80 asthmathics had similar results. In the study, black seed oil taken by mouth for 4 weeks improved asthma control. Scientists also observed a trend in lung function improvement .
Limited evidence backs up the benefits for diabetes. However, sudden drops in blood sugar can be dangerous for people with diabetes. If you are already on diabetes medications, be sure to talk to your doctor before supplementing with black cumin.
Several large analyses on thousands of people suggested that black seed may be a good complementary strategy for keeping glucose levels in check, especially in people with type 2 diabetes. It helped lower both blood glucose and blood lipids, possibly with long-term benefits (by also reducing HBA1C) [7, 8].
In a study (prospective) of 60 patients with insulin resistance, black seed oil (5 ml daily) improved fasting blood glucose levels. However, here it was only given as an add-on to glucose and lipid-lowering medications (metformin and atorvastatin) .
In patients with type 2 diabetes on oral anti-diabetes drugs, black seed supplementation helped to reduce heart complications. In a study of 114 patients, 2 g of black cumin seeds daily over one year reduced lipids, blood pressure, and BMI .
However, the current evidence is limited and inconclusive. Additional clinical studies are needed to determine whether black seed is beneficial for all people with diabetes.
3) High Blood Pressure
Daily use of black seed extract for 2 months lowered blood pressure in patients with mildly elevated blood pressure (systolic BP 140 – 159 mmHg). The test group received either 100 mg or 200 mg of the extract 2 times per day. Aside from reducing blood pressure, the extract also lowered “bad” LDL cholesterol, which may clog blood vessels .
In a different study of 70 healthy volunteers, the oil lowered blood pressure after 2 months. No adverse effects were reported. The treated group took 2.5 ml of black seed oil twice daily .
However, in another study (64 participants), the effects of powdered black seed capsules on blood pressure, lipids, and BMI were not statistically significant .
Similarly, in elderly patients with moderately high blood pressure (systolic BP 160 mmHg), black cumin seed extract had a statistically insignificant effect. In this study (76 participants), 300 mg of the extract was given 2 times per day for a month .
Finally, a large review of over 800 patients concluded that black seed may lower mildly elevated blood pressure, with black cumin seed powder having a stronger effect than the oil. The authors emphasized that it may help lower blood pressure in only mild cases and may take 2 months to achieve any effect .
All in all, the evidence to support the blood-pressure-lowering effects of black seed is weak and needs to be confirmed in larger studies.
Animal studies also looked into additional potential effects of black seed on the heart. For example, black cumin seeds improved the recovery of damaged heart tissue in rats (in response to heart surgery or post-heart attack treatment) .
In another rat study, both exercise and black seed increased heart blood flow and new blood vessels, potentially helping to prevent heart problems. These effects remain unexplored in humans .
4) Male Infertility
In a single, small study of 68 infertile men, daily intake of 5 ml (1 tsp) of black seed oil for two months improved semen quality without any adverse effects. We can’t draw any solid conclusions from this study, whose findings have not been replicated by other researchers .
In diabetic rats, black seed increased testosterone. It also improved sperm quality and motility in another rat study, probably due to its antioxidant activity. Additional research is needed [20, 21].
5) Breast Pain
Mastalgia is breast pain that may or may not be connected to the menstrual cycle in women.
In one clinical study of 52 women, a gel containing 30% black seed oil applied at the site of pain twice daily for two menstrual cycles reduced breast pain by about 82% . This was significantly greater than seen with a placebo gel, which reduced pain by 18% .
Insufficient Evidence for:
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of black seed for any of the below-listed uses.
Remember to speak with a doctor before taking black seed oil supplements. Black seed should never be used as a replacement for approved medical therapies.
6) Allergies and Hayfever
A couple of small-scale human studies suggest that black seed may help reduce allergic symptoms, especially in people with breathing difficulties.
One review (of 4 studies, a total of 152 patients with allergic diseases) concluded that black cumin seed oil may help with allergies. When used as an add-on to conventional therapy, it reduced subjective allergy symptoms, including asthma, eczema, and stuffy nose .
According to the review, patients received black seed oil capsules 40 to 80 mg/kg daily, which would be about 2 – 4 g of oil daily for someone who weighs about 110 lbs .
In another study of 66 patients with allergic rhinitis, black seed oil reduced symptoms such as itching, runny nose, sneezing, and congestion after 2 weeks. And in 39 patients with similar symptoms, 2 g daily of black seed cumin seeds after immunotherapy reduced symptoms and increased neutrophils [24, 25].
Despite these promising findings, large-scale, high-quality studies are needed to confirm the effectiveness of various black cumin seed oil preparations on allergic symptoms.
Some scientists believe that black seed may also help with breathing problems that are not caused directly by allergies. The boiled extract of the seeds improved breathing and lung function, reducing the need for inhalers, in a study of 40 chemical war victims who had breathing difficulties .
7) High Blood Lipids
Some scientists hypothesize that black seed may protect the heart by reducing blood lipids, which may help prevent atherosclerosis (hardening of the arteries) .
A review of clinical studies (SR-MA, 17 RCTs) concluded that black seed supplementation may help lower :
- Total cholesterol
- LDL cholesterol
However, scientists emphasize that further high-quality, randomized-controlled trials are needed to explore the effects of back cumin on lipid and cardiovascular health .
For example, in a small study of 10 patients with high cholesterol, 1 g of black seed powder before breakfast for 2 months also reduced the above-mentioned blood lipids . In a study of 88 similar patients (RCT), 2 g of black seed capsules lowered cholesterol, LDL, and triglycerides after a month .
How It Works
- Flushing excessive fluids from the body (diuretic)
- Reducing the fight-or-flight (sympathetic) response
- Increasing blood vessel-relaxing nitric oxide
- Lowering blood lipids
- Acting as an antioxidant
However, the above-mentioned mechanisms were mostly drawn from animal or cell-based studies and remain clinically unproven.
Black cumin seed (Thymoquinone) has promising anti-inflammatory properties. Some people think it is good for both Th1 and Th2 dominance, though the evidence is lacking.
Only several extremely small studies (with 4 and 1 patients) suggested that black seed oil may help with inflammatory conditions like arthritis.Much larger studies are needed. Black cumin’s anti-inflammatory potential was attributed to the active ingredient, thymoquinone, in animal studies .
In rats with arthritis, the active ingredient, thymoquinone lowered numerous pro-inflammatory cytokines (including IL-6, IL-1β, TNF alpha – Th1 cytokines) while increasing anti-inflammatory ones (IL-10) .
Some scientists believe that it may reduce brain inflammation by blocking NF-κB and preventing the immune cells from creating more nitric oxide, which is overly produced in inflammation and autoimmune diseases. However, their theories remain unproven [35, 36].
Insufficient evidence supports the purported benefits of black seed for anxiety. Despite some promising findings, additional clinical trials are needed.
Black cumin seeds decreased anxiety and improved mood and cognition in a study of 48 adolescent male volunteers after 4 weeks. The treated group took 1 g of black seed daily in capsule form .
Black seed extract reduced anxiety in mice , possibly by increasing serotonin levels in the brain. It also reduced anxiety and fatigue and increased thyroid function in mice. Such mechanisms remain to be researched in humans [39, 40].
Black cumin seed calmed and protected the developing brain in rats, even those who were under stress .
10) Poor Cognition
In a study of 20 elderly volunteers, 1 g of black seed daily improved cognition, attention, and memory after nine weeks. These findings remain to be replicated. We can’t draw any conclusions from a single, small, low-quality clinical study .
Thymoquinone and other components of black cumin seeds protected the brain from damage in several animal studies and cell studies. It prevented brain damage from lead in growing mice, as well as from arsenic. In growing rats with poor thyroid function, it helped prevent learning difficulties and brain damage. These effects remain to be researched in humans [44, 45, 46, 47].
11) Indigestion from H. Pylori
A tincture prepared from the seeds is traditionally used for indigestion, loss of appetite, and diarrhea, while black seeds are traditionally used to stop vomiting. So far, there is very limited evidence to support its use in those with indigestion due to Helicobacter pylori infection [2, 48].
In a study of 88 patients with indigestion positive for Helicobacter pylori, black seed helped eradicate the bacteria and symptoms. A minimal dose of 2 g of the seeds (in combination with omeprazole) was effective and comparable to standard triple antibiotic therapy, while both lower and higher doses were less efficient .
Some reviews suggest that it may also help protect the stomach lining from damage and ulcers, mostly based on findings from animal studies and clinical experience. Therefore, such claims remain unproven .
12) Weight Loss
The evidence is limited and mixed when it comes to black seed and weight loss, a traditional “indication” .
In one study of overweight men, black seed did improve weight loss and reduced appetite after 3 months. In another study of 64 patients, the seeds had no significant effect on BMI and waist-hip ratio [54, 14].
In fact, several studies found that black seed doesn’t help with weight loss .
Therefore, the current evidence suggests that black cumin seed is likely ineffective for weight loss.
13) Hepatitis C
Black Cumin seed improved symptoms and reduced viral load in patients with Hepatitis C in a study of 30 people .
In another study of 75 patients with hepatitis C, black seed alone (500 mg) or combined with ginger (500 mg) had similar beneficial effects .
These studies were small and potentially biased. Large-scale, multi-center clinical trials are needed to explore the effects of black seed preparations on hepatitis C and other viral infections.
Black cumin seeds (Thymoquinone) reduced symptoms of rheumatoid arthritis in a study of 40 female patients, at a dose of 500 mg of the oil 2X day. It reduced overall symptoms, joint stiffness, and swelling .
Aside from this study, no clinical data are available. Therefore, we don’t know if black seed affects arthritis. Additional research should be encouraged.
A black seed oil compound called thymoquinone reduced seizures in children with epilepsy in a pilot study of 22 children .
Without additional clinical studies, this purported health benefit remains unproven.
16) Opioid Dependence and Withdrawal
Black Seed helped reduce the symptoms of opioid dependence and withdrawal in a study of 35 opioid-dependant patients. It also helped reduce weakness, infections, and improve appetite. Additional research is needed .
Uses Lacking Evidence:
No clinical evidence supports the use of black seed for any of the conditions listed in this section.
Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
17) Antioxidant Defense
- Increasing liver antioxidant enzymes, such as glutathione
- Protecting various tissues from oxidative injuries, such as the stomach, liver, kidneys, and blood vessels
- Lowering homocysteine
The effects of black seed on these pathways in humans have not been investigated.
There are a couple of other animal studies we can’t draw any conclusions from. In one, black seed extract restored antioxidant enzymes (in red blood cells) in mice with malaria, which helped clear the parasite infection. In another study, the oil neutralized harmful Reactive Oxygen Species (ROS) and brain injury in mice [64, 59].
The exact benefits of its antioxidant activity in humans still remain to be researched.
Traditionally, people apply black seed oil to the skin to prevent infections and relieve pain .
Black seed has been researched for fighting various bacteria, viruses, and parasites, but the majority of studies were in animals, microorganisms, or cells. Therefore, this purported benefit remains unproven.
Some scientists found that black cumin seeds acts against:
- Staphylococcus aureus, a common cause of skin infections .
- MRSA (methicillin-resistant Staphylococcus aureus), a big problem when it comes to hospital-acquired infections that are hard to treat .
- H.pylori, a common cause of stomach ulcers (see benefit #7) .
- The formation of “Biofilms” .
Black seed oil also protected against mold (aflatoxicosis) in rats . Some researchers think that, with additional research, black seed may have potential for helping people with Chronic Inflammatory Response Syndrome.
Black seed helped fight the herpes-causing cytomegalovirus virus (CMV) in mice .
Black seed helped clear a malaria-causing parasite in mice .
The oil may protect against a parasite that damages the liver in mice .
In test tubes, black seed protected against several parasites that can cause serious gut issues in humans .
More research is needed.
19) Immune Enhancement
Cell studies suggest that potential immune-boosting effects of black seed may be due to its active ingredient, thymoquinone. In cell studies, it increased immune cell activity and antibody levels .
We can’t draw any conclusions from cell-based studies, though.
20) Kidney Health
Despite the lack of evidence, black cumin seeds have been traditionally used for the treatment and prevention of kidney stones .
Clinical studies are lacking.
21) Milk Production while Breastfeeding
Traditionally, black seed was used to help increase milk production during breastfeeding in nursing mothers. Human studies have not tested this claim, which remains unsupported by modern science. Black cumin seeds could stimulate milk production in rats [2, 81].
22) Muscle Relaxation
The effects on black seed on muscle relaxation in humans are unknown.
Black Seed reduced spasms in muscle tissues in various studies .
It has an effect only on smooth muscles, such as the heart, gut, and airways. This is the reason black seed is used for asthma, breathing difficulties, gut issues, high blood pressure, and potentially urinary tract issues.
Does black seed help with cancer prevention? The simple answer is: we don’t really know yet.
There is no evidence to suggest that black seed prevents cancer since its has mostly been studied in animals and cells.
The research we bring up is experimental and in the early stages. Keep in mind that human studies are needed before we can speak of any cancer-preventive effects.
Black seed oil protected against the immune-suppressing and damaging effects of radiation in rats .
In cells, it could kill cervical cancer, bone cancer, breast cancer, and stomach On the other hand, many substances can kill cancer in a dish. The majority of them fail further animal studies and human trials due to lack of efficacy or safety [90, 91, 2, 92].
Black Seed Oil Side Effects & Precautions
Proper safety trials with black cumin seed oil and its active ingredients have not been carried out. Limited evidence suggests that black seed is safe when used as a spice .
Although black seed is generally thought to be safe, several rare cases of skin allergies to the oil have been reported. These reactions are more common when black seed oil is applied to the skin.
The following side effects have also been reported in people using black seed oil by mouth:
- Gut-related complaints (constipation, burning, discomfort, vomiting, and nausea)
- Worsening of seizures
Since black seed can reduce blood sugar levels and blood pressure, people on medications for high blood pressure or diabetes need to speak with their doctor before supplementing.
Pregnant women should avoid taking black cumin seed extract or oil.
Black cumin seeds can cause abortions in larger amounts . Also, clinical studies have not confirmed that it is safe to use in pregnancy even in smaller amounts or in children.
Using Black Seed Oil
- Is rich in fatty acids particularly the unsaturated and essential fatty acids (Linolenic and Linoleic acid)
- Is also a source of Calcium, iron, sodium, and potassium .
- Contains Carotene (provitamin A) .
- Contains B-complex vitamins like Thiamin (B1), Niacin and Folic acid .
- Is a good source of Pyridoxine (Vitamin B6) .
Scientists are exploring whether garlic extract and black cumin seed oil may work better together to combat parasites .
Black cumin seed and garlic together may work together to lower high cholesterol, though the evidence is inconclusive .
Consumption of garlic extract and crude black cumin may have beneficial antioxidant effects in healthy postmenopausal women .
A typical dose of the oil, recommended by most manufacturers, is 2.5 – 5 ml 2X daily.
As crushed or powdered seeds, the dosage is typically about 1 g per day.
The following molecular targets have been identified by scientists in cell-based and animal studies. They do not translate to health benefits but help guide further research.
- Decreases LOX (Lysyl Oxidase) 
- Inhibits iNOS (inducible Nitric oxide synthase) 
- Inhibition of NF-κB (NF-kappa B) 
Proposed Anticancer Properties
- Activates PPAR-γ (Peroxisome proliferator-activated receptor gamma) 
- Increases PTEN (Phosphatase and tensin homolog) 
- Increases BAK/BAX 
- Decreases Bcl-2 and Bcl-xL 
- Suppresses the expression of AR and E2F-1 
- Increases the activity of Myeloperoxidase, Glutathione-S-transferase, Adenosine deaminase .
- Increases enzymes like Superoxide dismutase (SOD), Catalase and Glutathione peroxidase .
- Increases GABA (Gama Amino Butyric Acid) activity .
Activity in the Lungs and Trachea
Black seed or Nigella sativa is a flowering plant with a long history of traditional use, particularly in the Middle East. It should not be confused with cumin, an completely different spice with distinct potential health benefits.
Some evidence suggests that black seed may be beneficial in people with diabetes, asthma, high blood pressure, male infertility, and breast pain. Most other traditional uses–such as for enhancing digestion and immunity–have yet to be investigated in proper clinical trials.
Black seed is thought to be generally safe when used in amounts found in food, but skin allergies and gut complaints have been reported. It may also cause uterine contractions, which is why pregnant women should avoid it. Be sure to consult your doctor before supplementing.