Black seed oil is extracted from the seeds of Nigella sativa, a plant that belongs to the Ranunculacea family.
The use of black seeds and its oil has been traditionally used in medicinal therapies for thousands of years, and the herb was even described as “the Melanthion” by Hippocrates.
This product also has a long history of use in Indian and Arabian populations as a food, and is now used as a medicine to treat a variety of health conditions regarding the respiratory system, digestive tract, kidney and liver functions, cardiovascular system, and immune system.
The main active component of black seed oil is thymoquinone – a phytochemical within the plant which is largely responsible for the health properties of this herb.
1. Antioxidant Components
Many different compounds have been found within black seeds that are noted to give its antioxidant properties, such as thymoquinone, carvacrol, t-anethole and 4-terpineol .
Thymoquinone has shown to replicate the actions of superoxide dismutase. Superoxide dismutase is an important antioxidant defense in nearly all living cells exposed to oxygen, as it breaks down and stabilizes harmful free radicals that are known to cause many types of cell damage .
More to this, thymoquinone has demonstrated that it acts to scavenge pro-oxidative enzymes, and is associated with a significantly reduced overall level of oxidative stress .
Importantly, lab studies have also found that black seed oil, and not just black seeds, have great antioxidant effects .
It is likely for this reason that black seed oil can positively influence health and disease.
2. May Help to Reverse Dyslipidemia
Dyslipidemia is defined as the imbalance of one or more lipoproteins in blood, such as elevated triglycerides (free fatty acids in blood), high LDL (“good)”) cholesterol, and low HDL (“good”) cholesterol.
Studies have found that just 2 teaspoons of black seeds per day for 6 weeks, in patients with dyslipidemia, can decrease their LDL cholesterol levels and increase their HDL cholesterol levels .
However, use of black seed oil – 5ml per day for 8 weeks – has even shown to significantly decrease fasting blood cholesterol, LDL cholesterol, and triglyceride levels, in healthy individuals  . This finding is key, as most studies only see changes to cholesterol levels as an indirect result of reducing bodyweight in unhealthy populations.
Black seed oil seems to have a larger effect on cholesterol levels in comparison to black seeds, or black seed powder, especially when analyzing changes to HDL cholesterol.
Unlike most supplements aimed at reducing cholesterol levels, black seeds have also been reported to provide a notable benefit even when taken alongside strong cholesterol-reducing medications such as statins .
3. Can Potentially Prevent Diabetes
Diabetes mellitus is characterized by frequent and chronic elevations in blood glucose levels, which is a central factor in the production of reactive oxygen species that promote inflammation and cellular damage.
Use of black seed oil at 3 grams a day for 12 weeks has shown to cause improvements in insulin production (to remove glucose from the blood), as well as better fasting blood glucose and HbA1c levels; a form of haemoglobin that measures the average blood glucose levels for the previous 2-3 months .
Clinical trials have even seen significant reductions in fasting blood glucose levels at much lower doses of black seed oil; equivalent to oil obtained from only 0.7 grams of seeds .
Importantly, much like the effects of black seed oil on dyslipidemia, these beneficial effects have again been found without any significant changes in body weight .
Researchers have theorized that black seed oils anti-diabetic effects are mainly due to an improved functioning of β-cells, which are the cells responsible for making insulin within the pancreas.
4. Anti-Bacterial Properties
Lab studies utilising test-tubes have found that black seeds may have antibacterial properties, and therefore could be added to a diet with the purpose to kill harmful strains of bacteria.
The research so far has specifically highlighted black seeds effectiveness against a common strain of bacteria, Staphylococcus Aureus, one of the most common causes of skin infections that is difficult to treat with antibiotics .
The amount of black seed oil needed to remove this strain of bacteria is not yet known, although it seems to act in a dose-dependent manner.
Amazingly, in infants, black seed extracts that are applied topically are just as effective as antibiotics for treating bacterial infections on the skin, such as “staph” infections .
More research in humans needs to be conducted to further evaluate its impact on staph infections and look at how it affects other strains of bacteria in the body.
5. Could Help to Prevent Cancer
As black seeds are dense in antioxidants, it is possible they could help to prevent the formation and growth of cancer by neutralizing harmful free radicals.
The current scientific literature suggests most of black seeds anticancer or chemopreventive roles stem from the actions of thymoquinone, which has been analysed in different cancer cell lines and animal models for various types of cancer.
A key study reported that the antioxidative effects of thymoquinone are potent inducers of apoptosis, which is the controlled and programmed death of selected cancer cells .
Thymoquinone may also alter the activity of certain protein complexes, known as selective proteasomes, that are involved in the modulation of apoptosis in cancer cells .
However, some evidence is available that states thymoquinone is actually a prooxidant at higher concentrations, and therefore claims it can protect against cancer need to be made with caution .
Future research can hopefully clarify black seed oils direct effects on cancer growth.
Safety and Side Effects
Black seed oil has been established as a safe herbal product when taken in correct dosages.
Administration of black seed oil up to 5ml per day in healthy individuals has not reported any notable liver, kidney, or gastrointestinal side effects .
Black seeds in their original form have also not detected side effects when consumed up to 3 grams per day .
However, mild adverse impacts have been observed when dosages begin to rise over 5ml of black seed oil per day; including nausea, bloating, and burning sensations . These effects seem to be more common in dyspeptic patients – people that are irritable due to depression or indigestion.
In addition, although black seed oil may aid liver function, high intakes may also be harmful to the liver and kidneys. For this reason, those with pre-existing or current liver or kidney complication should consult with their doctor to determine the safety of black seed oil supplementation.
Pregnant women should also avoid the intake of this product as a pre-clinical trial found that the oil can potentially slow down uterine contractions when consumed in large amounts .
Black seed oil is extracted from the seeds of Nigella sativa and has been traditionally used in medicinal therapies for thousands of years.
The main benefits of this supplement are its antioxidative properties, which may have a positive impact on preventing or reversing dyslipidemia, type 2 diabetes, and cancer.
Limited data also suggests black seed oil may have antibacterial properties, especially against staph infections.
Black seed oil is generally safe to consume in most people when dosages are under 5ml per day.