Alena Clark, PhD, is a registered dietitian and experienced nutrition and health educator
Allison Herries, RDN, is a registered dietitian focused on preventing and managing chronic diseases through healthy lifestyle changes.
Black seed oil is a supplement extracted from the seeds of Nigella sativa, a flowering plant that grows in Asia, Pakistan, and Iran. Black seed oil has a long history dating back over 2,000 years.
Black seed oil contains the phytochemical thymoquinone, which can act as an antioxidant. Antioxidants detoxify harmful chemicals in the body called free radicals.
This article discusses the potential uses, risk factors, and side effects of taking the supplement.
Dietary supplements are not regulated in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. However, even if supplements are third-party tested, that doesn't mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check-in about potential interactions with other supplements or medications.
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent a disease.
Although research on the health effects of black seed oil is relatively limited, there is some evidence that it may offer potential benefits. Here's a look at several key findings from available studies.
Black seed oil may benefit some people with type 2 diabetes, according to a 2017 review published in the Journal of Pharmacopuncture.
Researchers reviewed four randomized, double-blind, placebo-controlled clinical trials with people who had taken black seed as oil, tea, or seeds. Results indicated that participants had a decrease in their fasting blood glucose. It is important to note that in most studies, black seed oil was consumed in addition to using oral diabetes medications, eating a healthy diet, and exercising.
A more recent study from 2020 aimed to evaluate the effect of black seed oil on inflammation, fasting blood glucose, and lipid profile in people with type 2 diabetes. The results also showed significant reductions in fasting blood glucose levels among those who received black seed oil capsules versus the placebo group.
According to a small study published in Immunological Investigations in 2016, black seed oil may help manage rheumatoid arthritis (RA).
In this randomized, double-blinded placebo-controlled study, 43 women with mild-to-moderate RA took black seed oil capsules or a placebo every day for one month. Compared to the placebo group, those who used black seed oil reported reductions in:
Black seed oil shows promise for treating allergies. For instance, in a 2011 clinical trial with 66 people published in the American Journal of Otolaryngology, when participants used black seed oil for two weeks, it reduced nasal symptoms including:
Another report published in 2018 analyzed data to determine if black seed oil could help treat sinusitis. Study authors concluded that the oil has multiple therapeutic effects, including:
Black seed oil may reduce risk factors in women who are obese, according to a study.
For the study, women consumed Nigella sativa oil or a placebo while following a low-calorie diet for eight weeks. At the study's end, the following levels had decreased by more in the group that took the Nigella sativa oil:
Another eight-week study enrolled sedentary women with excess weight and looked at the combination of aerobic exercise with black seed oil supplementation. In the study, one group took black seed oil, and another took a placebo; both used aerobic exercise.
Researchers found that the treatment combination of diet, exercise, and black seed oil provided benefits, including lowering cholesterol levels. It must also be noted that this trio also resulted in weight loss compared to the placebo groups but the benefits are unclear. Still, the authors concluded that further studies with a larger sample size and diet assessment are needed.
While black seed oil has been studied in human, lab, and animal studies for the below conditions, more research is needed. Please discuss your use of black seed oil with your registered dietitian nutritionist, pharmacist, or healthcare provider before using it for any of the following:
Consuming a supplement like black seed oil may have potential side effects. These side effects may be common or severe.
Very little is known about the long-term safety of black seed oil or how safe it is in amounts higher than what's typically found in food. However, some studies have found risks associated with black seed oil, including:
For these reasons, be sure to talk with your healthcare provider if you're considering taking black seed oil. In addition, remember that black seed oil is not a replacement for conventional medical care, so avoid stopping any of your medications without speaking with your healthcare provider.
Children and people who are pregnant or lactating should not take black seed oil remedies due to the lack of research into their long-term safety.
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.
Adults most often use black seed oil in doses of 1 to 2.5 grams by mouth daily for four to 12 weeks. Black seed powder has most often been used in doses of 1 to 2 grams by mouth daily for eight to 12 weeks. Speak with a healthcare provider to determine what dose might be best for a specific condition.
As a rule of thumb, never take more than the manufacturer's recommended dosage. If you experience side effects of any sort, stop taking black seed oil and call your healthcare provider.
It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.
It's also possible that black seed oil may interact with many common drugs, including:
It's also possible that black seed oil may interact with many common herb and supplement interactions, including:
Some people use black seed oil supplements to treat certain health conditions, including arthritis, allergies, asthma, and diabetes, and maintain a healthy weight. While some studies support health claims, most are small, and more research is needed.
Children and pregnant or lactating individuals should not take black seed oil. Certain drugs, herbs, and supplements can have interactions. Always consult your healthcare provider before starting a supplement.
Adults most often use black seed oil in doses of 1 to 2.5 grams by mouth daily for four to 12 weeks. However, you should always consult with your healthcare provider first to determine whether the supplement and dosage are appropriate for you.
Store black seed oil according to the manufacturer's directions. Discard as indicated on the packaging.
See below for more information on food and supplement sources of black seed oil.
Black seed oil has been used in many countries as a spice and food preservative. It can be purchased in stores as an oil or powder.
Black seed is often sold as a powder, tea, supplement, or oil. When buying a supplement, don't be fooled by claims that it can cure or treat any specific disease. Under the FDA labeling laws, it is illegal for manufacturers to make such claims, which are rarely supported by clinical evidence.
The FDA does not regulate black seed oil supplements, so use caution when choosing a supplement. Avoid those that make claims about treating health conditions, and look for certified cold-pressed products.
Some people use black seed oil supplements to treat certain health conditions, including arthritis, allergies, asthma, and diabetes, and maintain a healthy weight. While some studies support health claims, most are small, and more research is needed.
As a supplement, the FDA does not regulate black seed oil. You should use caution and work with your healthcare provider to determine if it is right for you and at what dosage.
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.
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