“Black seed” refers to the seeds of the plant Nigella sativa, which have been harvested for their therapeutic properties for thousands of years. Current research suggests black seed has favorable effects on several aspects of cardiovascular and metabolic health and possesses anti-inflammatory, antioxidant, antimicrobial, and immune-modulating properties that may benefit a variety of conditions.
Black seed is most often used for
Last Updated:March 15, 2024
Black seed is the seed oil or whole ground seeds of Nigella sativa — a flowering plant in the buttercup (Ranunculaceae) family that grows in certain parts of Asia, Africa, Europe, and the Middle East.[3] Black seed has a long history of use in many cultures, both as a spice in foods and as an herbal medicine. It contains a variety of nutritional compounds like polyunsaturated fatty acids, vitamins, and minerals, as well as an abundance of phytochemicals — thymoquinone (a terpenoid) being considered the most important.
Black seed has anti-inflammatory and antioxidant effects and immune-modulating properties. Currently, the most well-studied benefits of black seed are for cardiovascular health and metabolic health.[6]
Black seed may improve glycemic control by lowering fasting glucose and hemoglobin A1c (HbA1c) by a clinically significant degree. This effect is the greatest in people with type 2 diabetes, but benefits are still observed in other relevant conditions like metabolic syndrome and nonalcoholic fatty liver disease (NAFLD).[7][8][3][2]
Black seed may also improve lipid profiles, including reduced triglycerides, low-density lipoprotein (LDL) cholesterol, and total cholesterol, and increased [high-density lipoprotein (HDL) cholesterol.[3][8][7] This lipid-modulating effect has not been found in people with NAFLD despite other observed benefits in this population (reduced levels of liver enzymes, C-reactive protein, and liver fat).[9]
Lastly, black seed may reduce blood pressure, and in people with overweight or obesity, it may cause slight reductions in weight and body mass index (BMI).[10][11]
Most of these effects have been observed in short-term studies (≤12 weeks), meaning the long-term effectiveness of black seed supplementation still needs to be determined. An exception to this is the effect of black seed on glycemic control, with benefits being maintained in some studies spanning 6 to 12 months.[3]
Black seed is generally considered to be safe and well-tolerated. The most commonly reported side effects are gastrointestinal in nature, including diarrhea, nausea, vomiting, and heartburn.[12][6]
There have been several case reports of allergic skin reactions following the topical or oral use of black seed, ranging from mild dermatitis and hives to cases of Stevens-Johnson syndrome or drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, both of which are severe hypersensitivity reactions that can result in extensive blistering/rashes, fever, and potential damage to internal organs.[13][14]
Black seed contains many bioactive phytochemicals that likely contribute to its effects, but thymoquinone is considered its main active compound. Further, its content of polyunsaturated fatty acids, vitamins, minerals, and soluble fiber may have positive biological effects. Regardless, our current understanding of how black seed works is largely theoretical and based on animal and in vitro research.
Black seed may modulate lipid levels by several possible mechanisms, including reduced cholesterol synthesis (via downregulation of the rate-limiting enzyme HMG-CoA reductase), increased clearance of low-density lipoprotein (LDL) cholesterol from the blood, and increased synthesis of bile acids.[1]
Improved glycemic control may be due to reduced intestinal absorption of glucose (via inhibition of the sodium-glucose cotransporter), reduced synthesis of glucose by the liver, and improved integrity of pancreatic beta cells (insulin-secreting cells).[1]
Black seed also appears to activate AMPK in skeletal muscle and liver cells, which likely explains some of its antidiabetic and lipid-lowering properties.[15]
The anti-inflammatory and antioxidant effects of black seed may occur for several reasons, most likely through increasing the levels of antioxidant enzymes, reducing lipid peroxidation, inhibiting NF-KB activity, and reducing the formation of various inflammatory mediators.[6][3]
Black seed is typically taken in the form of an oil or a ground powder, taken orally at a dosage of 1 to 3 grams daily. For people with type 2 diabetes, preliminary research suggests that 2 grams daily may be the sweet spot for achieving beneficial effects on lipids and blood glucose.[1]
For topical use, most research has used preparations containing 10% to 20% black seed applied twice daily.
While black seed is available in various forms (seed oil, water extract, or whole ground seed), water extracts seem to be less effective, likely because thymoquinone (the main active compound in black seed) is fat-soluble. The whole ground seed and oil appear similarly effective, although more research comparing the two is needed.[2][3]
It’s important to keep in mind that the chemical composition of black seed can vary greatly depending on how it is grown, harvested, and processed. This could lead to inconsistent effects of black seed with seemingly equivalent doses.[4]
Because of the high content of polyunsaturated fatty acids in black seed, storing the supplement in the fridge in a dark, sealed container may help prevent oxidation.[5]
Full FAQ and database update
We expanded the existing FAQs to include more information about how black seed works, its drawbacks, its traditional uses, and how it might affect cardiometabolic health, skin health, asthma, allergies, and COVID-19. We also added 10 new meta-analyses to the Examine database.
One new meta analysis added
We added one additional meta-analysis to the database.
Reviewed By
