What is Black Seed? Benefits, Safety, Recommended Dose

FACT CHECKED

Black seed comes from the seeds of Nigella sativa, a flowering plant native to Southern Europe, North Africa, and Southwest Asia. In studies, black seed is often directly referred to as “Nigella sativa,” or “black cumin” more broadly, though the plant has no botanical relation to the earthy spice.

Biomedical interest in this traditional medicine has grown steadily over the last decade; according to PubMed, the National Library of Medicine’s database, the number of articles mentioning Nigella sativa published annually has increased from 277 in 2015 to 1,265 in 2025. 

Much of this research focuses on black seed’s main bioactive ingredient thymoquinone, a compound that has potential positive effects on the brain, kidneys, heart, gut, and liver. Researchers are also looking into black seed’s potential to help manage chronic conditions, support weight loss, reduce inflammation, and act as an antimicrobial and neuroprotective agent in the body. 

As of right now, studies on black seed are relatively poor in quality, making it difficult for biomedical researchers to come to definitive conclusions. However, recent reviews of existing research highlight a few areas of promise, especially the herbal remedy’s potential to reduce inflammation and improve metabolic markers like blood sugar.

Potential Benefits of Black Seed

Black seed has been used for centuries across many cultures and traditional medicine systems. In India, for example, it appears in Unani, Ayurveda, and Siddha practices. And in Islamic tradition, black seed is described in prophetic medicine and is sometimes referred to as a “remedy for all diseases.”

In these traditions, black seed is used to treat constipation, fever, cough, headaches, high blood pressure, arthritis, heart disease, toothache, skin disease, and more.

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Research is still catching up to these claims. A 2023 overview that included 20 meta-analyses on black seed health outcomes between 2013 and 2021 rated methodological quality low or “critically low” for all but one study; of the 110 evaluated outcomes in these analyses, 88 were found to be supported by very low-quality evidence, and only five reached “moderate certainty.” The overview’s evaluations are primarily made based on high risk of bias, inconsistent findings across studies, and imprecise data from small or poorly designed trials.

Despite these findings, the overview concludes on a somewhat optimistic note, stating that black seed “has the potential to improve different clinical outcomes, such as blood glucose, inflammatory markers, oxidative stress factors, serum lipids, blood pressure, liver and kidney parameters, and even asthma indicators,” but that higher quality research and larger sample sizes are needed to confirm these effects.

Studies on black seed health effects have been published since the review, with most recent meta-analyses focusing on inflammation and metabolism. Here are the latest:

Antioxidant and Anti-Inflammatory

Existing literature on black seed’s anti-inflammatory and antioxidant properties shows conflicting results, but a review of multiple meta-analyses published in the January 2025 issue of Prostaglandins & Other Lipid Mediators concludes that, despite these contradictory outcomes, black seed significantly lowered markers of inflammation and cell stress in the body.

Metabolic Improvements

A review of meta-analyses published in the October 2024 issue of Prostaglandins & Other Lipid Mediators concluded that black seed consumption significantly lowered fasting blood sugar (FBS) and HbA1c, a long-term blood sugar marker.

A review of eight randomized controlled trials, published in the April 2024 issue of West African Journal of Medicine, found that most studies showed black seed significantly improved lipid profiles, lowered blood pressure, and improved blood sugar control. The authors concluded that black seed can be recommended as a supportive therapy for metabolic syndrome.

The researchers also noted “a significant reduction in anthropometric measurements,” a term used to describe factors like BMI, but noted that these measurements were inconsistent across studies.

Are There Health Risks or Side Effects?

The Food and Drug Administration (FDA) lists Nigella sativa as “generally recognized as safe” (GRAS) when used as an ingredient in cooking (i.e as a spice, seasoning, or cooking agent). According to a narrative review published in Asian Biomedicine in 2020, no clinical trials to date have reported severe adverse effects in humans, and studies assessing its toxicity have found it safe.

However, it should be noted that while culinary use appears safe, caution is advised before using concentrated supplements, especially long-term or along with medications.

LiverTox, a free National Institutes of Health (NIH) database providing comprehensive information about drug-induced liver injury, reports that black seed users may experience mild side effects, including abdominal discomfort, bloating, diarrhea, and headache, and that rare reactions may include rash and skin hypersensitivity.

As is the case with many medications and supplements, there are limited studies of poor quality on black seed. Because it may impact each person in a unique way, it is best to speak to your physician prior to use.

Medication Interactions

While there are no reports specifically addressing black seed interactions, it is best to consult with your healthcare provider before introducing any new medication (prescription or over-the-counter) or supplement (vitamin, oil, herb, etc.).

“Foods, spices, and herbs can be powerful in a ‘food-as-medicine’ approach to health, and are generally very safe when used in everyday cooking,” says Alison Acerra, RDN, CDN, a functional nutritionist, hormone specialist, and MedShadow medical advisory panelist, “but high-dose supplements can act more like medication and may pose adverse reactions, so it’s wise to tread cautiously.”

How To Take Black Seed

Black seed can be used in a variety of ways. It can be taken as a daily supplement in capsule form (such as a black seed oil pill), and also has many culinary uses; in South Asia, for example, the oil is added to breads and pickles, and used to dress salads.

Additionally, if you choose to use black seed oil topically for the skin and hair, you can apply it directly to the affected area or mix it with other oils or skincare products, though there have been reports of black seed oil causing contact dermatitis.

Recommended Dosage

Studies on black seed use a wide range of doses in various forms, making it difficult to identify a standard dose. According to LiverTox, the typical recommended dose is 300 to 1000 mg, taken once or twice daily. As previously stated, there are potential health risks associated with exceeding the recommended daily dose.

How To Find Quality Black Seed

Black seed is available in both liquid and capsule form and can be found in health food stores or online. It is important to find trusted and reliable sources for your product. The FDA does not test supplements for safety or efficacy, so it’s best to look for products that are third-party tested for purity. MedShadow offers more advice on selecting safe supplements here.