Ultimate Guide to Black Seed Oil

Black seed oil, the Arabic seed of blessing, the rumored panacea to all your woes. Exactly how much truth is there behind this murky oil? Black seed oil is associated with a range of benefits and, in fact, many of the benefits are substantiated by clinical evidence. There is an incredible body of literature exploring and demonstrating the therapeutic benefits behind this oil, which is a testimony to its potent healing properties. Here, we dive deep into black seed oil, exploring how it works, what ailments it provides the most dramatic results for and what to look for when purchasing Nigella sativa products.

Table of Contents

What is black seed oil?

Black seed oil comes from the black seeds, or Nigella sativa, of the plant by the same name in the Ranunculaceae (buttercup) family. Seeds from the flower are generally cold-pressed, creating either an essential oil or fixed oil, which are yellowish or brownish in color. The seeds of the flower have likely been in use for thousands of years across Asia, Africa, Europe, the Middle East and the Far East.

The seeds have been traditionally used for a range of ailments including respiratory health, digestive complaints, diabetes, infections, rheumatism, and skin disorders, as well as for circulatory and immune system support. Many of these uses have seen been corroborated by contemporary scientific evidence. One of the longest-known, historical uses of black seed oil, as an aid for for dyspnea, or difficulty breathing, now has a significant number of studies demonstrating this. It’s remarkable fact that this use has been known for over a thousand years, dating back to the Persian physician Avicenna, who lived at the turn of the first millennia (born ~980 AD). This “father of early modern medicine” prescribed these seeds as a treatment for dyspnea [Dajani 2016] [Sommer 2021].

A brief history of black seed oil

Nigella sativa is so widespread and has been in continuous use for so long, it has since adopted many names across the world. In Arabic, it’s called habbatul baraka, meaning the seed of blessing. In the Old Testament (Isaiah 28:25,27), it’s referenced to as black cumin. In South Asia, it’s called kalonji, or black caraway seeds. In Hebrew, it’s ketash.

References to its use date back to Pliny the Elder, who lived in the first century AD. According to contemporary translations by John Bostock, a natural historian of the 19th century who reviewed the great work of Pliny the Elder, Natural History, Nigella sativa was associated with many uses at the time of Pliny. It was used to treat the wounds induced by serpents, scorpions and spiders, for runny noses or headaches, for “defluxions and tumours of the eyes”, for toothaches and for hardness of breathing. It also had a host of female health benefits associated with it including use as a galactagogue (to augment the milk in nursing mothers), to promote menstrual discharge and to accelerate after-birth (for the latter, simply by wearing 30 grains in a linen cloth attached to the body) [Bostock 1855].

It appeared that even two thousand years ago, people were aware of its toxicity. The same record acknowledged that if taken in too large a dose, it acts like a poison [Bostock 1855].

Black seed oil was even discovered in the tomb of the Egyptian pharaoh Tutankhamun. Not only does this indicate its use dating back to ~1300 BC, but furthermore provides compelling evidence about the nature of Tutankhamun’s death and the medicinal use of the seeds [Sommer 2021].

How does black seed oil work?

Lab studies reveal that black seed oil features a range of activities including:

  • anti-inflammatory
  • analgesic (pain-killing)
  • anti-diabetic
  • anti-hyperlipidemic
  • anti-convulsant
  • anti-microbial
  • anti-ulcer
  • anti-hypertensive
  • anti-asthmatic
  • anti-cancer
  • anti-tumor

In addition to these activities, the benefits of black seed oil also appear to stem from several mechanisms. Firstly, it has powerful antioxidant action, increasing defense against free radicals and promoting cellular apoptosis (normal and healthy cell death). Black seed oil also targets various inflammatory pathways, thus having an anti-inflammatory effect. Studies on rodents reveal that it reduces certain levels of inflammatory markers (like proinflammatory cytokines). Human studies show it decreases blood eosinophils (white blood cells which promote inflammation) in asthmatic patients. Lastly, Nigella sativa is also associated with immuno-modulating and cytoprotective mechanisms (the latter referring to its ability to protect cells) [Hwang 2021].

Although several compounds in black seed oil may contribute to the activities and corresponding benefits, the key active ingredient is thymoquinone. It’s the main pharmacologically active component of the essential oil, and some studies even focus on its effects alone [Dajani 2016].

Who benefits from black seed oil?

Based on all the studies below, we can say that black seed oil may be a promising therapeutic treatment for those with the following conditions:

  • Men with infertility
  • People suffering from asthma or respiratory issues
  • Those with hypertension (high blood pressure)
  • Type 2 diabetics (who are already taking oral anti-diabetic medication)
  • Those with skin conditions like acne or psoriasis
  • Those seeking to improve their memory

What kind to buy?

Black seed oil may be purchased in oil form, as well as in capsules (powdered seeds) or extracts. Studies demonstrate that the different derivatives are effective across a range of conditions. The two key things to know are that A) there is no standardization of active ingredients, thus it can be difficult to predict the effectiveness of any product, and B) different products may be appropriate for different conditions, based on the clinical research (i.e. topical versus oral, extract versus oil versus capsules).

Nigella sativa may be processed and produced in several ways. Most notably, it is available as an oil, extract or as capsules of finely milled seeds. The availability of the ingredients may vary among these categories as well as within them (i.e. not every oil has the same concentration). For example, the Iranian derived oil contains only 13.7% thymoquinone whereas Indian derived oil contains perhaps 50% [Dajani 2016]. The challenge with black seed oil is that there is no standardization of active ingredients. Some measures show that the concentration of thymoquinone, the key active ingredient, range significantly across different oil derivatives.

The good news is that the available literature on Nigella sativa indicates it may be effective in all these different forms. The most logical method to purchasing an effective supplement is to base the decision based on the available research. Thus, consult the dosing summary below to examine what extract type and what dosing was used for the condition of interest.

If you are able to identify the method by which the oil was prepared, you may be able to optimize the availability of the active ingredients. The evidence suggests that the best preparation of the oil first starts by roasting the seeds at 100 degrees centigrade for 10 minutes before processing the seeds (whether by creating the oil or extract, or simply milling the seeds into the final product) [Dajani 2016].

Additionally, sunlight degrades essential oils, and can lead to the chemical degradation of thymoquinone. When purchasing, it is best to look for products that have been stored appropriately. Continue to store your black seed oil in a cool, dark place after purchase, to prevent degradation.

Dosage and Type Breakdown

Studies vary in dosing, duration and the Nigella sativa used. Overall, use is generally long-term, often 2 months or longer of daily use. Typical clinical doses are around 5ml/day of oil or 2g/day of capsules. Effective topical cream may contain 10-20% black seed oil. Excess use can be dangerous as it may be toxic in high doses.

The dosage and method of treatment for black seed oil range significantly based on the condition being treated. Below is a summary of the dosing and type of Nigella sativa used in the studies reviewed here.

For male infertility:

For respiratory issues (asthma):

For hypertension:

Decrease weight & good for testosterone in obese men

For Type 2 diabetes (in addition to anti-diabetes drugs):

  • 2 or 3g/day of Nigella sativa capsules for 12 weeks [Bamosa 2010]
  • 5g/day of N. sativa seeds in tea for 6 months [El-Shamy 2011]
  • 2.5ml 2x daily of N. sativa oil for 3 months [Hosseini 2013]
  • 2g/day of N. sativa powdered capsules for 1 year [Kaatabi 2015]
  • 2 g/day of N. sativa powdered capsules for 1 year [Bamosa 2015]

For dermatological issues (topical or combination topical & oral is best):

  • For acne: Hydroalcoholic extract gel 2x daily for 8.5 weeks [Soleymani 2020]
  • For acne: Lotion with 20% N. sativa oil 2x daily for 8 weeks [Hadi 2010]
  • For psoriasis: 10% fixed oil extract [Jawad 2014]
Black seed oil has health benefits across the body
Benefits of Nigella sativa corresponding to body part, from [Tavakkoli 2017]

Benefits of Black Seed Oil – Human Studies

Black seed oil has been well researched for a range of conditions, providing a significant body of literature from which to determine its effectiveness on people. In this section we reveal the most compelling studies for its use and the conditions under which it was effective (i.e. dosage, duration of treatment, etc.).

Men’s Reproductive Health

The evidence suggests that black seed oil may be an effective treatment to enhance sperm health and fertility for men struggling with infertility, based on one clinical study and about a dozen rodent studies.

Infertility is often defined as a couple who cannot conceive after 12 months of trying. Infertility among men is likely more prevalent than most people think, although the exact prevalence is difficult to determine [Barratt 2017]. Oxidative stress plays a role, effecting structure, function, motility and survival of sperm. Plenty of lifestyle and environmental factors trigger mitochondria to produce reactive oxygen species, and thus oxidative stress. A significant portion of the reasons behind infertility in men are related to sperm dysfunction. Thus enhancing sperm health is generally beneficial to promoting fertility in men [Mahdavi 2015].

One study found that 2.5 ml of cold-pressed Nigella sativa oil 2x daily for 2 months enhanced sperm count, motility and morphology for infertile men. The men were identified as infertile because their existing semen samples at the start of the study were abnormal. The men in the study were infertile for more than one year, but otherwise healthy and not taking any other drugs the proceeding 3 months before the study [Kolahdooz 2014].

One study reviewed the evidence behind Nigella sativa for male infertility and concluded it positively influences sperm parameters, semen, Leydig cells (source of testosterone or androgens), reproductive organs and sexual hormones. They considered the human study discussed above, as well as roughly a dozen rodent studies. The primary mechanism at work is believed to be its antioxidant properties and thymoquinone’s ability to neutralize free radicals [Mahdavi 2015].

Anti-Asthma / Prophylactic

Contemporary evidence, along with its long-standing historical use, provide evidence of black seed oil’s ability to treat asthma.

One randomized double-blind study on 29 asthmatic adults found that 15ml/kg of 0.1g% boiled extract over 3 months significantly improved asthma symptoms in the treated group. Among the improvements was the frequency of asthma symptoms per week and chest wheezing, as well as an improvement in their pulmonary function tests (PFT). The benefits were seen after just 45 days, and continued after 3 months [Boskabady 2007].

One randomized double-blind study on 80 asthmatic patients found that 500mg 2x daily of N. sativa capsules for 4 weeks improved their asthma, as measured by the Asthma Control Test and the reduction in their blood eosinophils [Koshak Wei 2017].

Another study compared black seed oil (boiled extract) to the drug theophylline, one typically used for asthmatic patients. It’s worth noting that theophylline did work better than black seed oil. Nonetheless, the boiled extract still had significant anti-asthmatic effects in 50 and 100mg/kg doses, improving the patients pulmonary function tests (PFT) [Boskabady 2010].

The respiratory benefits of black seed oil are not limited to just those with asthma. One study evaluated the effectiveness of black seed oil on chemical war victims, those suffering from respiratory issues like wheezing. After 2 months of 0.375ml/kg of 50g% boiled extract daily, the participants respiratory side effects significantly improved compared to the placebo group. They improved with regards to their measured respiratory symptoms, chest wheezing and PFTs. By the end of the study, those in the treatment group were using their inhalers less often and sleeping better at night because they were wheezing and coughing less [Boskabady 2008].

It’s worth noting that some researchers are still skeptical about black seed oil’s use, and advocate larger scale clinical studies to better determine its efficacy [Koshak Koshak 2017].


Several studies provide compelling evidence that daily use of black seed oil over 2-3 months may significantly improve cholesterol and blood pressure.

Hypertension, or elevated blood pressure, is a risk factor for heart disease, stroke, renal failure, and other potentially fatal conditions. Several human trials indicate that Nigella sativa may provide a compelling treatment for high blood pressure, by its ability to decrease blood pressure.

One randomized double-blind study found that 100 and 200mg extract 2x daily for 8 weeks significantly improved blood pressure measures. Systolic blood pressure (SBP) and diastolic blood pressure reduced in the treatment group compared to placebo [Dehkordi 2008].

One randomized double-blind study evaluated 70 people with high blood pressure. The treatment group took 2.5ml 2x daily for 8 weeks of cold-pressed Iranian-bought Nigella sativa oil. Those who took the treatment had a significant decrease in their systolic & diastolic blood pressure compared to the placebo group [Huseini 2013].

Another randomized double-blind study found that 2.5ml 2x daily of black seed oil (versus placebo of sunflower oil) for 8 weeks significantly improved the cholesterol of hypertensive patients. Black seed oil significantly improved DBP, total cholesterol, and low density lipoprotein (LDL). Plus, it increased HDL (“good” cholesterol) [Shoaei Hagh 2021].

It’s worth noting one more study that did not find an improvement in cholesterol, but did feature other good outcomes. Here, the randomized double-blind study was done on obese men in hypertension stage I. Although it didn’t impact blood pressure much, they found taking 3g daily for 3 months (750mg NS 2x daily versus flour capsules) reduced body weight and helped inhibit decreases in serum free testosterone. Thus, black seed oil use also bodes well for testosterone levels [Datau 2010].


A significant and compelling body of evidence demonstrates the effectiveness of black seed oil in improving the diabetic health of those with Type 2 diabetes. Long-term, daily use over 3 months – 1 year results in significant decreases in HbA1c, fasting blood glucose and other measures of diabetic health.

For diabetics, anti-diabetes may, at first, sound like a strange term. Those with Type 1 diabetes understand it is a lifelong condition and those with Type 2 are familiar with the concept of controlling their blood glucose levels, but neither group may immediately be drawn to promises of “anti-diabetes”. In this context, the anti-diabetes activities of black seed oil are focused on Type 2 diabetics, to improve their blood glucose levels and corresponding reliable measures of diabetic health such as fasting blood glucose (FBG), blood glucose level 2 h postprandial (2hPG), and glycated hemoglobin (HbA1c). It’s worth noting that in some studies, the blood glucose of some patients improves so significantly that they no longer needed their typical anti-diabetic medications by the end of treatment.

The studies here focus on diabetics with Type 2 diabetes already taking anti-diabetic medication.

The literature provides compelling evidence of black seed oil’s benefits to improving diabetic control when combined with other anti-diabetic medication. Contrarian studies do exist, showing a lack of improvement, but the majority of evidence indicates a positive connection between daily supplementation with black seed oil and improved diabetic health.

One study found that 12 weeks of 2 or 3g/day of Nigella sativa capsules caused significant reductions in FBG, 2hPG, and HbA1c, as compared to the group that took only 1g/day. HbA1c was reduced by 1.52%. All groups continued to take their existing anti-diabetic medications, and the capsules were simply added as an additional treatment [Bamosa 2010].

One (non-double blind) study found that even a basic, daily tea of N. sativa improved many measures for Type 2 diabetics. Each participant took 5 g of N. sativa seeds daily through a tea (i.e. an at-home hot water extract) for 6 months. At the conclusion of 6 months, FBG, PPBG, HbA1c, blood urea, and serum bilirubin significantly decreased as compared to the measures at the start of the study. Aminotransferase (AST) and alanine aminotransferase (ALT) recorded a significant decreases as well. Impressively, the study reports that three patients ceased their existing anti-diabetic drugs at the end of treatment because their blood glucose had returned to the normal levels [El-Shamy 2011].

One randomized double-blind study found that 2.5ml 2x daily of N. sativa oil over 3 months significantly decreased blood levels of fasting and 2 hours postprandial glucose and HbA1c for Type 2 diabetics, compared to those who took placebo. Additionally, among the 35 people in the treatment group, their BMI decreased as well [Hosseini 2013].

Another randomized double-blind study on 114 Type 2 diabetic patients found that 2g/day of Nigella sativa capsules over one year decreased FBG, HbA1c and insulin resistance, among other measures. The treatment used was powdered 500mg capsules of Nigella sativa from Bioextract. Private Limited, Sri Lanka [Kaatabi 2015].

Yet another double-blind study, conducted on diabetics with HbA1c>7%, found that 2 g/day of N. sativa powdered capsules (from the same source as the previous study, BioExtract) over one year significantly decreased HbA1c. The researchers additionally evaluated the cardiac health of the patients, and found the treatment improved systolic function, as measured by echocardiography. Thus, N. sativa also provides therapeutic potential for the cardiac health of diabetics, who are, due to their condition, at increased risk of cardiomyopathy [Bamosa 2015].

Reviews on the use of N. sativa conclude it’s a beneficial treatment for Type 2 diabetes and its complications ([Hamdan 2019] review of 7 articles and [Heshmati 2015] review of 19 articles).

Dermatology Benefits

Some of the lesser known benefits of black seed oil are those pertaining to dermatology and as a treatment for a range of common skin conditions including acne and psoriasis. In fact, black seed oil is one of main medicinal plants frequently cited in traditional Persian medicine manuscripts for the management of acne vulgaris [Soleymani 2020]. Its ability to treat skin conditions is attributed to its antimicrobial, anti-inflammatory, and antineoplastic (chemotherapy resistance) activities.


The evidence suggests that topical application of Nigella sativa is an effective treatment for acne. 10-20% concentrated black seed oil topical treatments over 4-8 weeks significantly improve acne as compared to placebo.

One study found that black seed oil ointment was effective in treating psoriasis. Although they lacked a control group, the researchers compared patients who used a Nigella sativa ointment (10%w/w) versus those that took 500mg capsule 3x daily versus those who did both. 85% on those on the combination treatment had their psoriasis completely resolve after 12 weeks. Improvements were even noticed after only 4 weeks of treatment. The ointment used contained 10% Nigella sativa fixed oil extract and 90% vaseline (heated in preparation, to create a homogenized mixture). The capsules were made of grinded Nigella sativa seeds. Those using ointment or capsules alone also experienced a significant improvement in psoriasis, although the remission rates were higher as compared to those on the combination treatment [Jawad 2014].

Black seed oil was also demonstrated to be effective in treating acne vulgaris, the clinical term for acne. This randomized double-blind trial evaluated the effect of applying N. sativa hydrogel twice daily for 60 days on 60 acne vulgaris patients. Those using the gel had a significant reduction in the number of comedones, papules, and pustules compared to the control group. The scores of the acne disability index (ADI) questionnaire completed by the participants in the treatment group improved by 63% (versus placebo, which improved by 4%). No one in the study reported any adverse effects. The gel used was a hydrogel made of hydroalcoholic extract of N. sativa seeds (80% alcohol, 20% water) [Soleymani 2020].

Another randomized double-blind study found that using a N. sativa oil lotion (20% N. sativa oil, 80% solvent) for 8 weeks significantly improved the acne for those in the treatment group, with respect to non-inflammatory, inflammatory and total lesion counts. In fact, the lotion helped more than another group treated with benzoyl peroxide, a typical acne treatment. Additionally, those using N. sativa lotion had milder and fewer side effects. Benzoyl peroxide can be associated with side effects such as burning, irritation and redness. It’s worth noting the participants were also instructed to wash their face with a non-medicated cleanser, wait 15 minutes, and then apply the prescribed lotion twice daily (at morning and night) and told that no other treatments should be used [Hadi 2010].

Laboratory evidence also sheds light on biological activities that enable black seed oil to fight acne. One study compared a N. sativa oil antibiotic versus amoxicillin, the standard drug treatment, in how effective they are against p. acne (Propionibacterium acnes). They found that the methanolic extract of N. sativa inhibited the growth of p. acne as effectively as amoxicillin [Bhalani 2015].


Some evidence indicates that topical use of black seed oil, and particularly when combined with oral supplementation, helps alleviate psoriasis.

One study found that black seed oil ointment was effective in treating psoriasis. Although they lacked a control group, the researchers compared patients who used a Nigella sativa ointment (10%w/w) versus those that took 500mg capsule 3x daily versus those who did both. 85% on those on the combination treatment had their psoriasis completely resolve after 12 weeks. Improvements were even noticed after only 4 weeks of treatment. The ointment used contained 10% Nigella sativa fixed oil extract and 90% vaseline (heated in preparation, to create a homogenized mixture). The capsules were made of grinded Nigella sativa seeds. Those using ointment or capsules alone also experienced a significant improvement in psoriasis, although the remission rates were higher as compared to those on the combination treatment [Jawad 2014].

Safety and Side Effects of Black Seed Oil

Black seed oil is a relatively safe treatment, associated with few side effects for both oral and topical use. However, it’s important to note that black seed oil can be toxic and even lethal at extremely high doses and may not be appropriate to combine with certain medications and conditions.

Are there any side effects?

In the studies reviewed here, side effects were not reported for oral supplementation of black seed oil. Although rare, some side effects were reported for topical use, including irritation, burning sensation and redness.

Among the studies explored here, the majority do not report any side effects or adverse outcomes [Datau 2010] [Huseini 2013] [Dehkordi 2008].

In studies evaluating topical treatments, some side effects have been reported. There are two cases of contact dermatitis [Steinmann 1997] [Zedlitz 2002]. Both of these were treatable with topical corticosteroids [Ali 2003]. Additionally, in a study evaluating its use for acne, two patients reported mild irritation, burning sensations, and slight redness of the skin [Hadi 2010]. In another study on N. sativa gel use for acne, 14% of those in the treatment group displayed signs of hypersensitivity [Hwang 2021].

Is black seed oil safe?

Black seed oil is safe to take and side effects are rarely reported. However, at large doses black seed oil is associated with toxicity, so special care must be taken to dose properly and consult with professional healthcare practitioners.

Black seed oil is considered to be safe within the bounds of dosing, duration and use based on existing literature. Long-term studies (one year in length) provide evidence that long-term use is not associated with any side effects or adverse outcomes [Kolahdooz 2014] [Kaatabi 2015] [Bamosa 2015]. Studies evaluating doses up to 3g/day report no adverse outcomes [Hwang 2021]. Similarly, studies at 5ml/day for 8 weeks had no notable liver, kidney or gastrointestinal side effects [Tavakkoli 2017].

This being said, N. sativa is known to be toxic at high doses, based on toxicology studies on rodents. Several studies have computed the median lethal dose for rats and mice (this is the amount that would kill 50% of the population). Thus, special precaution should be taken to not exceed recommended dosing.

Is black seed oil safe for pregnant women?

There are no human studies to date evaluating the safety of black seed oil for pregnant women, thus we cannot conclusively say if it is safe for expecting mothers.

Some researchers stipulate that black seed oil is safe for pregnant women, although we do not yet have any clinical evidence on pregnant women to yet definitively know [Hussain 2016]. If pregnant, you are especially advised to consult a professional medical practitioner before taking black seed oil.

Some animal studies provide promising evidence that black seed oil may help ameliorate some health conditions in pregnant rats [Abdulrhman 2020] [Alsemeh 2019].

Black seed oil for COVID?

Due to black seed oil’s antiviral, antibacterial, anti-inflammatory and immunomodulatory activities, some researchers believe it may be a promising area of research for the treatment of COVID-19.

Black seed oil may have a compelling application and promising function for the prevention or treatment of COVID-19. Some researchers argue that the oil of nigella sativa contain the four critical activities that make it strong enough to treat COVID-19: antiviral, antibacterial, anti-inflammatory and immunomodulatory effects. This full-spectrum set of benefits makes it particularly promising for the treatment of COVID.

In addition to its four key activities, black seed oil also has antimalarial activity from the main active ingredient, thymoquinone, believed to be one of the first antimalarial drugs in history. Coincidentally, the first drugs used to treat patients infected with SARS-CoV-2 were antimalarial drugs, because their mechanism of action helped fight coronavirus. This research implies thymoquinone’s antimalarial properties make it a compelling area of treatment to explore for COVID.

It’s worth noting that the motivation behind this particular application actually dates back 2,000 years ago, to the Egyptian Pharoah Tutankhamun. The study arguing for black seed oil’s use as a therapeutic area of research for SARS-CoV-2 also had one more point. They observed that because Nigella sativa was discovered in the tomb of the pharaoh, it’s unlikely he died from malaria, a common belief among historians [Sommer 2021].

The bottom line on black seed oil

Black seed oil is a potent therapeutic treatment for a range of illnesses and conditions. Its list of biological activities and mechanisms is lengthy and this article may only be scratching the surface by covering some of its its anti-inflammatory, anti-diabetic, anti-hypertensive, anti-asthmatic and antibacterial properties. Although there is no such thing as a true panacea, a medicine that can cure anything, Nigella sativa comes as close as we can hope. Conversely, it doesn’t abide by the maxim that “more is better”. In too high doses, black seed oil can be toxic, thus it is important to abide by recommended dosing guidelines and to consult with a healthcare practitioner.

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