Black seed oil contains thymoquinone, which may offer support weight loss, improve skin conditions, health wounds, and help treat cancer and diabetes, among other benefits.

A person can use black seed oil topically or orally. Severe side affects are rare, though they may occur. This includes a possible allergic reaction.

In this article, we look at the science behind black seed oil’s benefits and explore the possible side effects and risks.

Black seeds are also known as black caraway, black cumin, kalonji, and black onion seeds.

They come from Nigella sativa, a small plant with pale purple, blue, or white flowers that grows in Eastern Europe, Western Asia, and the Middle East.

People have used the tiny black seeds of N. sativa fruits as a natural remedy for thousands of years. The seeds can also flavor curries, pickles, and bread in a similar way to cumin or oregano.

Black seed oil contains thymoquinone, which is an antioxidant and anti-inflammatory compound that may also have tumor-reducing properties.

People can ingest black seed oil in the form of capsules or apply it topically to benefit the skin. It is also possible to add the oil to massage oils, shampoos, homemade skincare products, and fragrances.

High quality black seed oil is also suitable for use in cooking, baking, and beverages.

Scientists with a range of specialties have researched the possible benefits of black seed oil.

However, it is important to note that many studies to date have used cells or animals as models, and there is limited research available on the effects of black seed oil in humans.

Benefits for weight loss

A review of 11 studies has shown that black seed supplementation may help lower people’s body mass index (BMI) and lower people’s waist circumference. The study participants did not report any severe side effects from taking this supplement.

A 2021 study on rats fed a high fat diet shows that black seed oil may be able to help significantly decrease body weight and insulin resistance.

Beauty benefits

Black seed oil may be beneficial by helping clear symptoms of skin conditions such as eczema, acne, or psoriasis.

Black seed oil may also hydrate hair, soften skin, and act as a moisturizer, although there is a lack of scientific evidence to confirm these benefits.

Benefits for health conditions

Black seed oil may also be beneficial for some health conditions, including the following:

Wound healing

Black seed oil may be able to speed up the process of wound healing.

The exact science of how this works is not clear, but researchers theorize it may also be connected to the antioxidant and anti-inflammatory properties of thymoquinone.

In addition, it also increases collagen formation. This, along with its cosmetic benefits, can help with wound healing.

Cancer

Research has shown that the thymoquinone in black seed oil can influence programmed cell death in several types of cancer cells. These include brain cancer, leukemia, and breast cancer cells.

However, much of the research on the effects of black seed oil on cancer uses cells rather than live humans, so researchers do not yet know how effective the oil may be to treat cancer in people.

Liver and kidney function

Research has also shown that the antioxidant properties of black seed oil can have a protective effect on both the liver and the kidneys.

There are several mechanisms by which this works. In one of the key processes, thymoquinone appears to reduce the level of oxidative stress, which is an imbalance of free radicals and antioxidants in the body.

Oxidative stress is associated with a variety of liver problems such as alcoholic liver disease, cirrhosis, liver damage caused by Tylenol, hepatitis, and others. It is also associated with kidney problems such as chronic kidney disease and kidney toxicity.

A 2019 study also shows that black seed oil may be helpful in reducing the size of kidney stones and eliminating kidney stones from the body.

Gastrointestinal problems

The anti-inflammatory properties of black seed oil may also help alleviate symptoms like indigestion, nausea, abdominal distention, bloating, vomiting, diarrhea, or constipation.

Some clinical studies have shown that the oil may even have a preventive effect on colitis, pancreatitis, and other gastrointestinal disorders. However, more research is necessary to pin down the exact benefits of black seed oil in this area.

Hypertension

A 2016 meta-analysis has shown that black seed oil can help reduce hypertension (high blood pressure).

In this analysis of 10 randomized controlled trials, administering the supplement showed a reduction in both the systolic and diastolic blood pressure among participants.

On the other hand, a clinical trial focusing on older adults with high blood pressure found that the reduction in blood pressure among participants who received the supplement was not significant when compared with the placebo group.

It is important to note, however, that it is possible in some cases to experience low blood pressure as a result of using black seed oil. Speak with a doctor before using it to reduce your blood pressure.

Diabetes

Black seed oil may have antidiabetic properties and improve blood sugar levels. A 2019 review of studies shows that the oil may help reduce a person’s blood glucose, hemoglobin, and insulin resistance.

This research suggests that it could be used as a treatment for type 2 diabetes along with conventional treatments.

Infertility

A 2014 clinical trial in men with abnormal sperm and infertility has found that black seed oil may improve sperm movement and increase sperm count and semen volume.

The findings of a more recent 2018 study on male mice confirm that the key ingredient thymoquinone can help boost the quality, motility, viability, and count of sperm cells.

Although black seed oil seems to offer certain health benefits, this supplement does not replace medication. People taking medication should talk with a doctor before using herbal supplements such as black seed oil.

The doctor can advise on possible interactions with the medication and also discuss the potential benefits and side effects of the supplement. It is essential to consult a doctor before stopping any prescribed medication.

As with any supplement, pregnant or breastfeeding people should talk with a doctor to see if black seed oil is right for them before using it.

Serious side effects from black seed oil are rare. Taking it as an oral supplement may cause:

With topical use, black seed oil can cause a severe allergic rash in some people. Therefore, it is vital to test it on a small patch of skin first to ensure that it does not trigger a reaction. People must also take care to keep the oil away from the eyes, nostrils, and other sensitive body parts.

In addition, thymoquinone may inhibit certain drug-metabolizing enzymes, which means that a person should avoid using the oil while taking a medication that may be impacted as a result.

To get the safest and most beneficial black seed oil, always choose high quality, organic black seed oil that is 100% pure, therapeutic grade, and U.S. Department of Agriculture (USDA) certified.

The Food and Drug Administration (FDA) labels black seed oil as Generally Recognized as Safe. However, the FDA also does not test supplements for safety or effectiveness. For this reason, looking for a product from a reputable provider is important.

A person can search the database of the USDA for certified companies that produce or sell black seed oil. Other resources to find high quality products include ConsumerLabs, the U.S. Pharmacopeia, and NSF International.

The dosage a person should use may depend on the type of inflammation, condition, or issue they want to alleviate. A person should speak with a doctor to make sure that using black seed oil is safe for them and to determine the right dose.

However, one 2021 study on the safe levels of the component of thymoquinone shows that adults should limit usage to 900 milligrams (mg) of the oil or 48.6 mg of thymoquinone daily in order to reduce the risk of side effects.

People have used black seed oil for its therapeutic benefits for thousands of years.

Many studies have shown that it may have health and cosmetic benefits for various medical and skin conditions, although these studies often use animal or cell models rather than humans. More research into the effects of N. sativa in humans is necessary to confirm its benefits.

Many health stores sell black seed oil, and it is available in both liquid and capsule form online. However, a person should always talk with a doctor before taking black seed oil and choose 100% pure, therapeutic grade, USDA-certified organic black seed oil.

The FDA does not monitor herbs and supplements for quality and purity, so it is vital to be selective when purchasing these products.