What to Know About Nigella Sativa (Black Seed)

Nigella sativa (N. sativa) is an annual flowering plant native to parts of Africa, India, Asia, and the Mediterranean. It is part of the genus Nigella and the family Ranunculaceae and is most commonly regarded as a medicinal plant.

N. sativa has been used for centuries in various forms of alternative medicine, including folk medicine and Ayurveda. It is sometimes referred to as one of the most significant medicinal plants of all time.

Also known as black cumin or black seed, N. sativa is traditionally used to treat many health conditions. Thymoquinone, the main bioactive compound of N. sativa, is thought to be responsible for many of the herb's potential health benefits.

This article will cover the traditional uses of N. sativa, paying special attention to what the research says. It will also discuss the nutritional benefits, side effects, precautions, dosage, and toxicity of N. sativa.

Nutrition

N. sativa seeds contain both macronutrients and micronutrients essential to your health.

Regarding macronutrients, N. sativa seeds contain protein, fat, and carbohydrates. The seeds are also a source of dietary fiber and various amino acids, including:

• Glutamate
• Arginine
• Cysteine
• Methionine

Important micronutrients (vitamins and minerals) can also be found in the seeds of N. sativa. These include:

• Iron
• Copper
• Zinc
• Phosphorus
• Calcium
• Thiamine
• Niacin
• Pyridoxine (vitamin B6)
• Folic acid

Hundreds of phytonutrients (substances produced by plants that may have health benefits) are also present in N. sativa. Examples of these phytonutrients include:

• Alkaloids
• Saponins
• Plant sterols
• Essential oils
• Thymoquinone

The presence of these compounds and nutrients may be why N. sativa has been used in traditional medicine for thousands of years.

Traditional Uses of Nigella sativa

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

N. sativa is a popular herb in many types of traditional medicine, such as traditional Chinese medicine (TCM) and Ayurveda (an ancient traditional medicine system in India). Both the seeds and seed oil are often used to treat a wide array of conditions in these and other types of traditional medicine.

Traditionally, N. sativa has been used for conditions such as:

• Bronchitis
• Asthma
• Diarrhea
• Skin disorders
• Liver disease
• Digestive issues
• Poor appetite
• Parasites
• Decreased breast milk supply

N. sativa is also thought to support the immune system and protect the liver, kidneys, and digestive tract. Various studies have shown that N. sativa possesses a number of additional properties, including:

• Diuretic (reducing fluid buildup)
• Antihypertensive (reducing blood pressure)
• Antidiabetic (reducing blood glucose, or sugar, levels)
• Anticancer (preventing tumor growth)
• Antimicrobial (reducing the spread of infections)
• Analgesic (reducing pain)
• Anti-inflammatory (reducing pain and inflammation)
• Antioxidant (protecting against harmful molecules known as free radicals)

However, most studies performed on N. sativa have taken place in a laboratory rather than in humans. Therefore, not all traditional uses of N. sativa are supported by scientific evidence.

What the Research Says

It's important to look at the research when considering trying a new dietary supplement. Fortunately, there are a fair amount of clinical trials on N. sativa and its potential role in various conditions. These trials give us a starting point when it comes to discussing the use of N. sativa with healthcare providers.

A review of N. sativa discussed several clinical trials that have been performed on the herb.

It should be noted that some studies have shown mixed results regarding how well N. sativa works. Therefore, precautions should be taken before using N. sativa to treat a health condition. Remember, also, that supplements should never replace standard care.

Below is a more in-depth look at some research on N. sativa in certain health conditions.

May Improve Blood Sugar

Studies have suggested that compounds in N. sativa may help people with type 2 diabetes lower their blood sugar.

Various clinical trials have shown the potential of N. sativa to act as a complementary diabetes treatment. A systematic review of 13 clinical trials noted improvements in blood sugar control, including decreases in fasting blood sugar and HbA1c (hemoglobin A1c, a blood test showing the average glucose level over the past three months). Some of the trials also reported improvements in insulin sensitivity due to using N. sativa.

N. sativa may also aid in diabetes prevention.

One study compared N. sativa to metformin (a diabetes medication) and lifestyle changes to see which intervention may be best for people with prediabetes (high blood glucose levels that are not high enough to be considered diabetes).

N. sativa produced similar results as metformin regarding anthropometric (e.g., weight, body mass index) measurements and blood sugar control. The herb also improved lipid panels and inflammation in people with prediabetes.

Although these results are promising, some researchers believe more extensive human trials are needed. There is still much to learn when it comes to the dosing and safety of N. sativa for diabetes.

May Promote Heart Health

Thymoquinone and other compounds in N. sativa have been associated with beneficial effects on heart health. Specifically, studies have shown that N. sativa may be beneficial for high blood pressure, hyperlipidemia, atherosclerosis, and heart damage.

According to one review, N. sativa use has been linked to improvements in both systolic and diastolic blood pressure, possibly due to diuretic properties. These results have been seen in healthy people as well as those with metabolic syndrome.

The same review noted several animal studies in which N. sativa improved blood lipids. In short, N. sativa has been shown to increase high-density lipoprotein (HDL) cholesterol (considered “good”) and decrease low-density lipoprotein (LDL) cholesterol (considered "bad"), total cholesterol, and triglycerides in rabbits.

In a small, long-term study, N. sativa was used daily with a blood sugar–lowering medication for one year in people with diabetes. Compared to a placebo group, those who added N. sativa to their regimen had significant improvements in total cholesterol and LDL/HDL cholesterol ratios. Adding N. sativa also led to improvements in heart rate and blood pressure.

If you have heart disease, talk with a healthcare provider before using N. sativa, as research is still emerging. Additionally, like other herbs, N. sativa may interact with certain medications.

May Improve Memory & Cognition

Lab and animal studies have found a potential relationship between N. sativa and cognition. What this research has shown is that N. sativa improves memory and recall. Some small human trials have found similar results.

A study of 40 healthy older adults compared N. sativa to a placebo to see if either affected memory, attention, and/or cognition. Those randomized to receive N. sativa took 500 milligrams (mg) capsules of the herb two times a day for nine weeks. At the end of the study, N. sativa was found to have a significant positive effect on logical memory as well as attention and cognition.

Another small trial tested N. sativa in healthy adolescent males between the ages of 14 and 17. This study randomized participants to take smaller doses of N. sativa for shorter periods than the previous study (500 mg daily for just four weeks vs. twice daily for nine weeks). N. sativa was found to positively affect mood, anxiety, and cognition in the participants, but not significantly better than the placebo.

More research is needed in this area. Larger and longer human trials would provide more information to help researchers determine the role of N. sativa in memory and cognition.

May Be a Complementary Treatment for Certain Skin Conditions

N. sativa essential oil may be used topically to treat various skin conditions.

A systematic review of randomized controlled trials concluded that N. sativa may indeed play a role in the treatment of conditions such as:

• Atopic dermatitis, or eczema
• Psoriasis
• Vitiligo
• Acne

In most of the studies included in the review, N. sativa was used topically rather than orally. However, oral N. sativa may also have positive effects on these and other skin conditions.

One study compared the effects of N. sativa with betamethasone (a steroid) and Eucerin (a lotion) for hand eczema. In the study, participants between 18 and 60 years old were randomized to use one of the three treatments twice daily for four weeks.

Both N. sativa and betamethasone improved hand eczema significantly more rapidly than Eucerin.

A different study compared N. sativa to fish oil for the treatment of vitiligo. The 52 participants were randomized and applied either N. sativa essential oil or fish oil to their vitiligo lesions two times a day. By the end of the six-month trial, N. sativa showed more significant improvements in the size of vitiligo lesions than fish oil.

Hopefully, studies will continue to be conducted to strengthen these and other research results that show a positive effect of N. sativa on skin conditions.

May Alleviate Inflammation

Inflammation is a natural process that may result from injury, infection, or disease. Compounds found in the seeds and seed oil of N. sativa may help reduce this inflammation.

The effects of N. sativa on inflammation and oxidative stress were assessed in a recent systematic review. From the 10 clinical trials included in the review, it was concluded that N. sativa reduced inflammatory biomarkers like C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-a) and increased antioxidant capacity.

N. sativa may also act as a complementary treatment for people with rheumatoid arthritis (RA), an autoimmune disease marked by chronic inflammation and joint pain, according to some studies.

A small study compared N. sativa oil to a placebo in 42 people with RA. N. sativa was used by half of the participants at a dose of 500 mg twice daily for eight weeks. The results showed that N. sativa increased anti-inflammatory cytokines and reduced pro-inflammatory cytokines in people with RA.

As mentioned in various studies and reviews, more research is needed to further confirm if and how N. sativa alleviates inflammation.

What Are the Side Effects of Nigella sativa?

N. sativa is generally considered safe for most people to use. Various studies on the herb have paid close attention to possible side effects and the overall safety of N. sativa. In these studies, very few side effects have been reported for N. sativa.

Although rare, possible side effects of taking N. sativa include:

• Nausea
• Bloating
• Hypoglycemia (low blood sugar)
• Skin irritation
• Constipation
• Abdominal cramps
• Indigestion
  

These side effects tend to be mild and should resolve once you stop using N. sativa. If side effects persist or become worse, talk with a healthcare provider.

Precautions

Although N. sativa is considered safe, some people should avoid using it.

In general, children and adults should only use N. sativa for short periods and in proper doses. Taking large doses of N. sativa or using it for too long may increase the risk of side effects.

People who are pregnant or breastfeeding should avoid using N. sativa supplements. While N. sativa used in food may be OK, there isn't enough reliable information to know if larger doses found in supplements are safe. In fact, there is some evidence that N. sativa may slow contractions in the uterus, which could be harmful to a fetus.

Because N. sativa might increase the risk of bleeding, it's recommended that people with bleeding disorders or those who have upcoming surgeries don't use it.

Other precautions may be warranted, but more research is needed on the safety of N. sativa. Always talk with a healthcare provider before using a new supplement, especially if you have a health condition or take prescription medications.

Interactions

Sometimes, supplements can interact with medications, herbs, nutrients, or other supplements. These interactions may cause medications, herbs, nutrients, or supplements to work improperly in your body.

N. sativa may interact with certain medications, herbs, and supplements. However, these possible interactions are not well-documented. Regardless, there is concern that N. sativa negatively interacts with the following:

• Norvasc (amlodipine)
• Neoral, Sandimmune (cyclosporine)
• Medications, herbs, or supplements that decrease blood sugar
• Medications, herbs, or supplements that decrease blood pressure
• Immunosuppressants
• Medications, herbs, or supplements that increase serotonin
• Medications, herbs, or supplements that slow blood clotting
• Central nervous system (CNS) depressants
• Diuretics
• Any herbs/supplements that act as sedatives
• Iron

Other interactions may exist, so it's important to check with a healthcare provider before using N. sativa if you take any medications or use other herbs or supplements.

Also, it is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients are included. Please review supplement labels with a healthcare provider to discuss any potential interactions with foods, other supplements, and medications. 

Dosage: How Much Nigella sativa Should I Take?

N. sativa dosage typically depends on various factors, including your age and reason for use. Because there are no set guidelines for N. sativa dosage, it's best to follow dosage directions as provided on your supplement's label.

Based on the available evidence, N. sativa oil is typically used at a dose of 1 to 2.5 g per day for four to 12 weeks. N. sativa powder, on the other hand, is often used at a dose of 1 to 2 g per day for eight to 12 weeks.

Varying doses of N. sativa have been used in clinical trials. While a dose of 1 g of N. sativa per day has been shown to increase HDL cholesterol after three months, higher doses of 2 to 3 g per day have been shown to significantly decrease total cholesterol and triglycerides in people with type 2 diabetes.

Similarly, using N. sativa for nine weeks at a dose of 1 g per day has been linked to improved memory and cognition in healthy older adults.

If you're unsure how much N. sativa you should take, talk with a healthcare provider to get personalized dosage recommendations.

What Happens If I Take Too Much?

N. sativa is not known to be toxic. Regardless, it's important to only use N. sativa in recommended doses.

Some animal studies have looked at the potential toxicity of N. sativa and found that a dose of 2.4 g per kilogram (kg) of body weight (g/kg) was lethal to mice. This level of toxicity has never been seen in humans. In a person weighing 150 pounds (68 kg), this would equal an extremely large dose of 163 g of N. sativa, which is 81 times or more than the average adult dose.

It's important to keep in mind, though, that taking a larger than recommended dose of N. sativa may increase the risk of side effects like cramping or indigestion. Play it safe and only use N. sativa as directed.

Sources of Nigella Sativa & What to Look For

N. sativa can be used as a food or a supplement. Typically, you can get larger doses of N. sativa in supplement form, but there may be advantages to using the herb as a food.

Remember that dietary supplements can never replace a well-balanced diet. While supplements may fill in nutrient gaps for some people, it's best to aim to get all the nutrition your body needs through food.

Food Sources of Nigella Sativa

The seeds or oils from N. sativa may be used to add flavor to foods.

N. sativa seeds are said to have a bitter taste and smell. These seeds may be ground and used similarly to black pepper. Or, N. sativa seeds may be used to flavor certain types of candy, liquor, bread, and cheese.

N. sativa is more commonly used as a supplement, however.

Nigella Sativa Supplements

You can easily find and purchase N. sativa supplements online. These supplements may also be available in certain grocery or retail stores as well as nutrition or supplement shops.

N. sativa supplements may come in capsules, powders, soft gels, liquid extracts, or essential oils. And while the majority of research focuses on N. sativa as an oral supplement, certain forms may also be used topically.

Although N. sativa is naturally vegan and gluten-free, some supplements may contain animal-based ingredients or gluten. Be sure to check the ingredient list to ensure the supplement meets your dietary preferences or needs.

Summary

Nigella sativa is a medicinal plant popularly used in various types of alternative medicine. Research shows that N. sativa may benefit blood sugar, heart disease, memory impairment, skin conditions, and inflammation. However, in many cases, additional studies are needed to further prove the efficacy of N. sativa in these and other conditions.

If you think N. sativa might be beneficial for your health, talk with a healthcare provider to learn more and make sure it's a safe supplement for you.