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- Black seed oil benefits include helping with weight loss, hair growth, and treating acne.
- Black seed oil side effects include constipation, nausea, vomiting, and bloating.
- Therefore, start with 1/2 a teaspoon of black seed oil a day to give your body time to adjust.
- Visit Insider's Health Reference library for more advice.
Black seed oil is a supplement extracted from the seeds of Nigella sativa, a flowering plant native to southwest Asia.
The seeds of Nigella sativa have been used in traditional medicine worldwide for the treatment of different ailments and diseases, like skin disorders and digestive issues.
Modern science is starting to back up some of these claims, and while this research is promising, more studies are needed to draw definitive conclusions about the benefits of black seed oil.
Here's a look at the science behind some of the benefits of black seed oil.
1. Reduces high blood pressure
Blackseed oil may help lower blood pressure, but study results are mixed. A 2016 review cited four studies that supported this benefit and five studies that saw no benefit on blood pressure.
For example, a small 2013 study of adults taking ½ teaspoon of black seed oil twice a day showed a significant improvement in blood pressure after about eight weeks.
Scientists do not yet know exactly why black seed oil may help lower blood pressure but one reason could be its high thymoquinone content.
2. Lowers cholesterol
Black seed oil is high in polyunsaturated fatty acids, which boost the "good" cholesterol in our bodies and lower the "bad," says Skylar Griggs, RDN, founder of Newberry Street Nutrition a nutrition consulting business.
In fact, a small 2015 study of obese women who took 3 grams of black seed oil per day for eight to 12 weeks while on a low-calorie diet found it significantly lowered their LDL ("bad") compared to the participants who followed the same low-calorie diet but took a placebo, instead.
In another small 2015 study, participants with type 2 diabetes who took 3 grams of black seed oil per day for 12 weeks also saw significantly lowered LDL cholesterol and triglyceride.
3. Helps with weight loss
Some studies have found that black seed oil may also help reduce body mass index (BMI) in individuals with obesity or type 2 diabetes. However, scientists are not yet clear why.
For example, a small 2015 study of obese women who took 3 grams of black seed oil per day in addition to a low-calorie diet lost more weight overall than the placebo group who followed the same low-cal diet.
And, in a 2018 review of black seed oil's effects on weight loss, researchers found the supplement led to an average weight loss of about 4.4 pounds (2.1 kilograms).
4. Reduces acne
You can also apply black seed oil topically to reduce inflammation in the skin and help alleviate acne.
In fact, a lotion containing 20% black seed oil extract has been found to be just as effective, if not more, than benzoyl peroxide, in treating and reducing breakouts.
In a small 2010 study, 97% of participants who used 20% black seed oil lotion saw more than half of their acne lesions disappear while only 50% of participants using 5% benzoyl peroxide lotion saw the same. The black seed oil lotion group also demonstrated fewer side effects, like skin irritation and itching, than the benzoyl peroxide group.
5. Moisturizes skin
When used topically, black seed oil may also moisturize the skin and treat some skin conditions, like eczema, though studies so far are limited.
A small 2013 study found that applying black seed oil twice a day for four weeks was just as effective at reducing the severity of hand eczema as traditional treatment options, including the use of over-the-counter Eucerin lotion and prescription topical steroid Betamethasone.
6. May stimulate hair growth
Many people report that black seed oil helps hair grow and prevents hair loss. However, there is no conclusive research to support this claim, Griggs says.
Yet, a very small 2014 study of three participants found black seed oil may encourage hair growth due to its significant amounts of proteins and fatty acids, which can boost blood circulation, and therefore, stimulate hair growth.
The study applied different mixtures of coconut oil to four areas of shaved participants' heads and found the coconut and black seed oil mixture promoted more hair growth after four weeks than three other coconut oil mixtures.
7. May improve sperm count
Some studies suggest black seed oil may improve sperm count in men diagnosed with infertility.
For example, a small 2014 study of infertile males with abnormal sperm counts found that men who took 2.5 ml of black seed oil daily for two months saw a significant improvement in sperm count and mobility compared to men who took a placebo.
How to use black seed oil
You can find black seed oil supplements in capsule or liquid forms online or at a specialty health food store, like Whole Foods or Natural Grocers. Hoscheit recommends looking for cold-pressed 100% pure Nigella sativa.
Because black seed oil is not regulated by the US Food and Drug Administration (FDA), it's important to consider checking dosage and brands with a doctor or dietitian.
That said, most black seed oil supplements suggest 1 to 2 teaspoons daily. However, Hoscheit says that if you're new to this supplement, start off easy with ½ tsp per day to give your body time to adjust.
Who should not use black seed oil
Black seed oil should be safe for most healthy people, but it can interact with certain medications, like beta-blockers, so it's important to speak with your doctor or a registered dietitian before giving it a try.
If you have any kidney issues, check with your doctor before starting a black seed oil supplement because one case study found it was associated with kidney failure.
Additionally, due to limited research, black seed oil is also not recommended during pregnancy or breastfeeding, Hoscheit says.
Insider's takeaway
Some research indicates supplementing with black seed oil may lower cholesterol, reduce blood pressure, or even help you lose weight. When used topically, black seed oil may also help reduce acne and moisturize skin.
However, the studies conducted thus far are small or in animals which means more large-scale human studies are needed to determine its effect on the general population as well as dosage recommendations.
So discuss with your doctor before taking black seed oil as they can recommend the right dosage for your individual needs as well as determine if it's safe to take in the first place.