What to Know About Black Seed Oil

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Black seed oil is an herbal ingredient that’s been used in the treatment of a variety of illnesses for more than 2,000 years. Black seed oil is derived from the seeds of the flowering Nigella sativa plant. Some people also call the seeds black cumin or black caraway.

Black seed oil is believed to have numerous health benefits. It is available in both capsule and liquid form and can be used either orally or topically, depending on the condition you want it to help. People have used the oil as a way to help manage asthma, acne, diabetes, and more.  

Benefits of Black Seed Oil

Because numerous cultures have long used Nigella sativa for so many reasons—ranging from asthma to back pain—there has been much current-day research done on the plant and its oil. The studies have shown that there are many potentially effective benefits to reap from black seed oil. 

Most of the health benefits seem to come from thymoquinone, a chemical compound in the plant. 

Fights Bacteria

Some research has shown black seed oil has antimicrobial effects, meaning it can fight off harmful bacteria. 

One study found that black seed oil seemed to stop or slow the activity of certain Gram-positive bacteria, which can cause infections.

Black seed oil also seemed to be effective against multi-drug resistant bacteria, such as MRSA, or Methicillin-resistant Staphylococcus aureus. These bacteria tend to be hard to treat because they have developed an immunity to some antibiotics and treatments. 

High in Antioxidants

Black seed oil has antioxidant effects, largely due to a phytochemical in the oil called thymoquinone. 

Thymoquinone is an antioxidant that can fight free radicals, which are unstable molecules in the body that can damage the DNA in your cells. Over time, that damage can increase your chances of developing certain diseases, including cancer. 

Thymoquinone has been studied for its potential in helping to treat cancer and other diseases.

Improves Allergy Symptoms

Some research has shown black seed oil can help relieve certain allergy symptoms. 

One small study found that people who applied a topical black seed oil preparation for six weeks experienced some relief from their allergic rhinitis (hay fever) symptoms, like sneezing; an itchy or runny nose; and itchy, watery eyes.  

The black seed oil seemed to be most effective for people with mild symptoms, so the benefit may vary depending on the severity of your allergies. 

More research is needed to determine how effective black seed oil would be in the long term and how it compares to traditional allergy medication.

May Improve Lung Function

Some research has also shown that one of the chemical compounds the plant produces,   thymoquinone, can fight inflammation.  

This can be particularly beneficial for conditions involving inflammation in the lungs, such as asthma. Asthma is a condition in which the airways inside the lungs become inflamed, making breathing difficult. A review of multiple studies found that black seed oil seems to help relieve the symptoms of asthma. However, many of the clinical studies are small, which suggests that more research is needed. 

Another study found that a black seed oil supplement significantly improved lung function and decreased inflammation in people with another type of lung disease, chronic obstructive pulmonary disorder (COPD). Those results suggest that black seed oil could become an additional therapy for people with this type of inflammation. 

Provides an Antifungal Effect

Research also suggests that black seed oil has antifungal properties, meaning it can slow or stop the growth of fungi organisms. This can become beneficial when treating a fungal infection in the body. Some research has shown black seed oil may even be as effective as the commonly used antifungal medication Ambisome (amphotericin B). 

May Help With Weight Loss

Some research suggests taking black seed oil may increase weight loss. 

One review of multiple studies found that people who took a black seed supplement lost, on average, more weight than a group of people taking a placebo. Black seed is believed to suppress the appetite. 

Improves Acne and Other Skin Conditions

Due to black seed’s antibacterial and anti-inflammatory properties, the ingredient may also improve certain skin conditions and the appearance of skin, hair, and nails. 

Some research suggests black seed oil can be used to treat acne as well as psoriasis and hyperpigmentation. It may also be used to help heal small wounds. 

Other research found that using a topical preparation containing black seeds seems to help treat hand eczema.

Black seed oil may also help to hydrate your hair and nails when directly applied.  

May Lower Blood Pressure

Taking black seed in a powder or oil form may help slightly reduce blood pressure. Most research has shown the improvement in blood pressure is fairly small, ranging from a 2mmHg to a 11 mmHG drop in systolic and diastolic levels. There is not yet enough research to determine if black seed could help people with hypertension, or high blood pressure.

May Help with Diabetes

Some research has shown black seed may help manage diabetes and other metabolic conditions like hyperglycemia (high blood sugar) by reducing blood sugar levels. This may be due to black seed’s ability to reduce oxidative stress as an antioxidant, which could increase the production and activity of insulin. Insulin regulates the amount of glucose (sugar) in the blood.

However, more research is needed to confirm this benefit. 

How to Take Black Seed Oil

You can buy black seed oil supplements in liquid form or in capsules. Black seed oil in liquid form is known for its strong flavor; mixing the oil  with honey or lemon can help dilute the taste. 

If you want to use black seed oil with the goal of improving the appearance of your hair or nails, you can massage the oil into your skin, on your scalp, or around your nail beds. You can also buy products containing black seed extract like shampoo, hair masks, creams, oils, and soaps. 


There is not currently a standard dosing recommendation for black seed oil.

Varying research has studied the use of black seed oil in doses of 1-3 grams daily for four to 12 weeks.

There is not enough research available to recommend taking a black seed oil supplement for longer than three months.

If you decide to try a black seed oil supplement, talk to a healthcare provider about finding the right dose for you.  Be sure to mention any other supplements and medications that you’re taking, too. 

Is Black Seed Oil Safe?

Research suggests that black seed oil is non-toxic. Several studies have examined the oral and topical use of black seed oil and have not uncovered any serious adverse effects.

However, some research has reported that people experiencing functional dyspepsia, which is a type of long-lasting stomach pain not caused by an ulcer, might experience adverse effects after taking black seed oil. Some of these side effects include nausea and bloating. Talk to your healthcare provider before trying black seed oil if you have this functional dyspepsia. 

People who are pregnant or breastfeeding should also avoid using  black seed oil as there is not enough evidence to show it is safe to use during that time.

Potential Drug Interactions

While black seed oil is considered to be relatively safe, it may interact with certain medications or supplements. Talk to a healthcare provider before using black seed oil, especially if you take or are planning to take any of the below drugs.

  • Anti-clotting drugs: If you take an anticoagulant (blood thinner) to slow blood clotting, using black seed oil could increase the effect and slow your clotting even more. This might increase your risk for bleeding and bruising.
  • Blood pressure medications: Black seed can lower your blood pressure. If you are also taking medication to lower blood pressure like Norvasc (amlodipine) or another hypertensive drug, you could become at risk to experience severely low blood pressure. . 
  • Diabetes medications: Black seed can cause your blood sugar levels to drop. If you are already taking a diabetes medication to control your blood sugar levels, the pairing could cause your blood sugar to drop too low. 
  • Diuretics: Some people take diuretics to remove extra salt and water from their bodies. Both diuretics (also known as water pills) and black seeds can lower your potassium levels. If your potassium levels drop too low, you may experience muscle weakness, fatigue, or even abnormal heart rhythms.   
  • Immunosuppressants: Because black seed can help boost the immune system, it might undermine the effect of any medication you’re taking to reduce your immune system’s activity. For example, you may take an immunosuppressant after undergoing an organ transplant surgery. 
  • Iron supplements: Black seed oil could increase the amount of iron your body absorbs. If you are also taking an iron supplement, you may experience adverse effects as a result of having too much iron. 
  • Sedative drugs: You might experience some sleepiness when you use black seed oil. If you’re taking a sedative medication that also makes you sleepy or slows down your breathing, black seed may increase this effect. 
  • Serotonergic drugs: Black seed oil may increase the levels of a chemical in your brain called serotonin. If you’re already taking an antidepressant medication like a selective serotonin reuptake inhibitor such as Prozac, Lexapro, or Celexa, the addition of black seed could increase your serotonin levels too much. This could lead to side effects such as seizures, vomiting, and heart problems. 

What to Look For

The U.S. Food and Drug Administration (FDA) does not regulate supplements the same way that it regulates medications. This means the FDA does not review dietary supplements to make sure they are safe and effective before they are marketed for sale. 

When buying a supplement like black seed oil, it’s important to compare products and look closely at the label. Look for a product that a third-party organization has tested for quality. Typically, you can find this information on the product’s bottle or the company’s website. 

Third-party groups test dietary supplements to determine if they contain the ingredients they claim to contain. These testing organizations include ConsumerLab.com, NSF International, and U.S. Pharmacopeia (USP).

Can You Take Too Much Black Seed Oil

While black seed oil is generally considered safe, there is not enough research to show whether it’s safe to take in larger amounts or for long periods of time. Due to lack of research, it is best to take a daily black seed oil supplement for no longer than three months. 

Black seed oil does have the potential to interact with several medications and other supplements. Even a small amount of black seed oil may become harmful if you are taking another type of medication that produces similar effects. 

Side Effects of Black Seed Oil

Black seed oil may increase the effect of certain medications that you take. Some people may experience other side effects from black seed oil, including: 

  • Rashes from an allergic reaction
  • Upset stomach 
  • Vomiting 
  • Constipation

If you experience any of these side effects, seek medical care. If you are concerned about potential side effects—especially when coupled with other medications or supplements that you’re taking—talk to a healthcare provider before taking black seed oil.

A Quick Review

Black seed oil is an herbal extract that offers several benefits such as reducing mild allergy symptoms and improving the appearance of skin and hair. Black seed oil is generally considered safe for most people to take for a limited period of time. However, black seed oil may interact with other medications, including immune system-suppressing drugs and medications for treating high blood pressure and diabetes. Talk to your healthcare provider about any concerns before taking black seed oil.

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  1. Tavakkoli A, Mahdian V, Razavi BM, Hosseinzadeh H. Review on the clinical trials of black seed (Nigella sativa) and its active constituent. J of Pharmacopuncture. 2017;20(3):179-193. doi:10.3831/kpi.2017.20.021

  2. Natural Medicines. Black seed.

  3. Ahmad MF, Ahmad FA, Ashraf SA, et al. An updated knowledge of black seed (Nigella sativa Linn.): Review of phytochemical constituents and pharmacological propertiesJ Herb Med. 2021;25:100404. doi:10.1016/j.hermed.2020.100404

  4. Ahma A, Husain A, Mujeeb M, et al. A review on therapeutic potential of Nigella sativa: A miracle herbAsian Pac J Trop Biomed. 2013;3(5):337–352. doi: 10.1016/S2221-1691(13)60075-1

  5. Mohammed S, Amin H, Aziz S, et al. Structural characterization, antimicrobial activity, and in vitro cytotoxicity effect of black seed oil. eCAM. 2019;9. doi:10.1155/2019/6515671

  6. Sizar O, Unakal CG. Gram positive bacteria. StatPearls. StatPearls Publishing. 2022. 

  7. Alkhatib H, Mawazi SM, Al-Mahmood SMA, Zaiter A, Doolaanea AA. Thymoquinone content in marketed black seed oil in Malaysia. J Pharm Bioallied Sci. 2020;12(3):284-288. doi: 10.4103/jpbs.JPBS_208_20

  8. National Institute of Health. Antioxidants: In depth

  9. Mohamed Alsamarai A, Abdulsatar M, Hamed Ahmed Alobaidi A. Evaluation of topical black seed oil in the treatment of allergic rhinitis. Anti-Inflammatory & Anti-Allergy Agents in Medicinal Chemistryrrent Medicinal Chemistry - Anti-Inflammatory and Anti-Allergy Agents). 2014;13(1):75-82.

  10. Koshak A, Koshak E, Heinrich M. Medicinal benefits of Nigella sativa in bronchial asthma: A literature review. Saudi Pharmaceutical Journal. 2017;25(8):1130-1136.doi:10.1016/j.jsps.2017.07.002

  11. Al-Azzawi MA, AboZaid MMN, Ibrahem RAL, et al. Therapeutic effects of black seed oil supplementation on chronic obstructive pulmonary disease patients: A randomized controlled double blind clinical trial. Heliyon. 2020;6(8):e04711. doi:10.1016/j.heliyon.2020.e04711

  12. Eid AM, Elmarzugi NA, et al. A review on the cosmeceutical and external applications of nigella sativa. J Trop Med. 2017;2017:7092514. doi: 10.1155/2017/7092514

  13. Namazi N, Larijani B, Ayati MH, Abdollahi M. The effects of Nigella sativa L. on obesity: A systematic review and meta-analysis. J Ethnopharmacol. 2018;219:173-181. doi:10.1016/j.jep.2018.03.001

  14. Yousefi M, Barikbin B, Kamalinejad M, et al. Comparison of therapeutic effect of topical Nigella with Betamethasone and Eucerin in hand eczema. J Eur Acad Dermatol Venereol. 2013;27(12):1498-1504. doi:10.1111/jdv.12033

  15. Hamdan A, Haji Idrus R, Mokhtar MH. Effects of nigella sativa on type-2 diabetes mellitus: A systematic review. Int J Environ Res Public Health. 2019;16(24),4911. doi:10.3390/ijerph16244911

  16. Hassanien MFR, Assiri AMA, Alzohairy AM, Oraby HF. Health-promoting value and food applications of black cumin essential oil: An overview. J Food Sci Technol. 2015;52(10):6136-6142. doi:10.1007/s13197-015-1785-4

  17. Koshak A, Wei L, Koshak E, et al. Nigella sativa supplementation improves asthma control and biomarkers: A randomized, double-blind, placebo-controlled trial. Phytother Res. 2017;31(3):403-409. doi:10.1002/ptr.5761

  18. Mahdavi R, Namazi N, Alizadeh M, Farajnia S. Effects of Nigella sativa oil with a low-calorie diet on cardiometabolic risk factors in obese women: a randomized controlled clinical trial. Food Funct. 2015;6(6):2041-2048. doi:10.1039/c5fo00316d

  19. Medline Plus. Black seed.

  20. Medline Plus. Low blood potassium.

  21. U.S. Food and Drug Administration. Dietary supplements.

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