Black Walnut Extract (Juglans Nigra) Uses, Benefits, Dosages & Side Effects

Black walnut has been used for centuries as a natural medicine in Russian, Chinese, and Native American cultures. [4]

Historically, the hulls of these nuts have been used as a laxative and for skin conditions such as eczema, psoriasis, parasitic skin infections, and warts. [2, 5]

Purported health benefits of black walnut supplements include reducing inflammation, stimulating circulation, supporting cardiovascular health, and acting as an antioxidant. [3]

Black walnut extract is also purported to support the immune system, skin health, digestion, and exhibit antimicrobial effects against parasitic organisms. [1, 2]

Most of these claims are based on anecdotal reports and traditional use. Clinical research needs to be conducted to determine the therapeutic effects of black walnut.

This article will review what black walnut extract is, how it works, supplement uses, benefits, side effects and potential drug interactions.

Black Walnut Extract

Plant Extract

Antioxidant

Parasites

Heart Health

How It Works:

• Traditionally used as an anti-parasitic agent
• Supports cardiovascular health
• May have antioxidant effects

Dosage:

Varies depending on formulation

Safety:

Rated Possibly Safe

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Black Walnut Plant Description

Black walnut trees are deciduous, meaning they shed their leaves annually.

The trees are hardwoods that commonly grow over one hundred feet in height, have short trunks, and develop large, round-topped crowns. [2]

They are native to the east-central and Midwest regions of the United States, as well as southeastern Canada. [2]

The trees were introduced to Europe in the mid 1600s and have been used there as food and medicine since that time. [1]

Black walnut (Juglans nigra) is one of less than two dozen species in the Juglans genus. Juglas regia, the English walnut, is the most common. All are members of the Juglandaceae botanical family. [2]

Female black walnut flowers develop clusters of 4-5 hard, green-hulled nut fruits. Both the nuts and their hulls have been used for centuries in traditional medicine. [2]

The fruit of the black walnut is edible. The nuts are sometimes eaten plain, as well as commonly included in baked goods and ice cream. [2]

Extraction of the nut from the hull is difficult as they are tightly bound together. For the best tasting walnuts, it is necessary to remove the hulls when they are still green. [2]

Medicinal Uses for Black Walnut

Ancient Romans and Greeks considered the walnut a symbol of fertility. Pliny the Elder is said to have studied the medicinal properties of walnuts in the 1st century AD. [2, 5]

Walnuts have been found in prehistoric deposits in Europe dating back to the 8th century. During the Middle Ages (5th-15th centuries) in Europe, walnuts were used to treat epileptic fits and to protect against witchcraft. [2]

In the 17th century, English botanist and herbalist Nicholas Culpepper recommended using black walnut for drawing the venom out of snake and spider bites. [3]

Native Americans have used the husks, bark, leaves, and nuts of this plant medicinally for centuries. It was used for skin conditions, as insect repellent, as a laxative, and for removing parasites from the body. [5]

Some other traditional medicine uses include:

• Colic (severe abdominal pain, normally because of intestinal obstruction)
• Fever
• Glandular disturbances
• Hemorrhoids
• Kidney problems
• Skin conditions including eczema, acne, pruritus, psoriasis and warts
• Toothache
• Upset stomach and recurring diarrhea [2, 4]

Other folk uses for black walnut include treating frostbite, rickets, blisters, ulcers, itchy scalp, and sunburn. It has also been used for irritated eyes, conjunctivitis (inflammation of the conjunctiva of the eye), and styes (eyelid infection). [2]

According to the Natural Medicines Comprehensive Database (NMCD) some of the common uses of this supplement include: [3]

• As an anthelmintic (destroys parasitic worms)
• Diphtheria (highly-infectious bacterial infection of mucous membranes)
• Leukemia
• Syphilis

Black walnut extract and tincture is used topically as a mouthwash, insecticide, and hair dye. It is also applied to the skin for minor wounds. [3]

Black Walnut Nutritional Profile

The Global Healing Center (GHC) reports that black walnut is becoming a popular dietary supplement because of its excellent nutritional profile. It is particularly in demand due to its high concentration of polyunsaturated fatty acids. [4]

Dr. Edward Group states, “The high fatty acid content of black walnuts has earned it added appreciation. The essential fatty acids, along with sterols, are known to benefit the heart and cardiovascular system [and] weight loss efforts.” [4]

A 1-ounce serving of this nut provides roughly:

• 1.9 grams fiber
• 2.8 grams carbohydrate
• 6.7 grams protein [5]

According to Drugs.com a 100-gram serving contains about 700 calories. The fat or oil content is estimated to be approximately 60%. [2]

Organic Facts reports that, “Black Walnut is so highly praised because it has a distinctly higher content of fatty acids and protein than its more commonly used cousin, the English walnut. This high concentration of omega-3s and unique organic compounds is what gives black walnut such a good nutritional profile.” [2]

According to the NMCD and Doctor’s Health Press (DHP), black walnuts contains:

• A hydroxycinnamic acid called caffeic acid
• A natural phenol antioxidant called ellagic acid
• A quinoid constituent called plumbagin
• A yellow pigment called juglone (5-hydroxy-1,4-naphthoquinone)
• Antioxidants such as myricetin, quercetin, kaempferol, taxifolin, and stigmasterol
• Astringent polyphenolic biomolecules called tannins
• Beta-sitosterol
• Melatonin
• Monounsaturated fatty acids
• Phytosterols
• Polyphenols
• Various sesquiterpenes [3, 5]

Both juglone and plumbagin have been observed to have cytotoxic effects, meaning they can kill cells. [3]

Juglone has shown action against various parasitic worms, tobacco mosaic virus, and Helicobacter pylori. Juglone has also shown anticancer effects in vitro including slowing tumor growth and inducing apoptosis (cell death) of cancer cells. [5]

Plumbagin has demonstrated neuroprotective, anticancer, and antimalarial properties in in vitro studies. [5]

Black walnut contains multiple vitamins, including A, C, E, and K. It also contains various B-complex vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), and B9 (folic acid). [5]

Juglans nigra nuts and hulls also contain various minerals including iron, sodium, zinc, calcium, phosphorus, potassium, selenium, magnesium, copper, and manganese. [5]

The nuts of these trees contain the same bioactive compounds as the hulls. However it is thought that the concentration is greater in the hulls. Black walnut extracts and powders are made primarily from the hulls. [3]

How Does Black Walnut Work?

The NMCD reports the following pharmacological effects associated with black walnut observed in in vitro and animal studies:

• Anti-inflammatory (reduces redness and swelling)
• Antimicrobial (kills or inhibits growth of harmful microorganisms)
• Antioxidant (reduce or removes free radicals)
• Cardiovascular (affects the heart and blood vessels)
• Cytotoxic (kills cells)
• Dermatological (relating to the skin)
• Gastrointestinal (relating to digestion) [3]

At this time, research in humans is lacking. Clinical studies are needed to determine if the mechanisms of action seen in in vitro and animal studies are also seen in humans.

Antimicrobial effects

In one laboratory study, black walnut extract demonstrated strong activity against Listeria monocytogenes. Listeria infection is most often contracted after eating foods contaminated with the bacteria. It causes fever, headache and other flu-like symptoms. [3]

Anti-inflammatory and Antioxidant Effects

In both in vitro and animal studies, black walnut extract has been observed to have anti-inflammatory and antioxidant effects.

The polyphenols in this nut exhibited antioxidant effects in various in vitro studies on animal and human cell cultures. [3]

This nut also contains ellagic acid. It is thought that the ellagic acid causes most of the anti-inflammatory effects. [6]

While it exhibits anti-inflammatory effects on human and animal cells in vitro, it is also used to induce laminitis in research studies on horses. Laminitis is inflammation of sensitive tissue (laminae) inside the hoof. [3]

Cardioprotective Effects

Consumption of walnuts is purported to have cardioprotective effects, meaning it may reduce the risk of heart disease. According to the US Food and Drug Administration (FDA), essential fatty acids in walnuts can protect against cardiovascular risk factors.

The FDA has issued a qualified health claim that says, “eating 1.5 oz. per day of walnuts as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.” [3]

Gastrointestinal Effects

Black walnut has been used in traditional medicine for centuries as a treatment for diarrhea and constipation. Juglone is believed to induce a normalizing effect on intestinal tissue. [3]

Various tannin constituents in this nut are astringents. This means that they may reduce secretions, ease irritation, and may improve the firmness of intestinal tissue. [3]

While some of the specific compounds in this walnut have been studied for their effects on gastrointestinal health, research using black walnut supplements for digestion is lacking.

Purported Health Benefits

The Global Healing Center states that the phytosterol, fiber, and fatty acid content in black walnuts may help support:

• Metabolism
• Normal blood glucose levels
• Normal blood lipid (fat) balance
• Weight maintenance [4]

According to Dr. Edward Group III, black walnut hull may support blood sugar regulation, improve factors related to metabolic syndrome and support healthy weight management. [4]

The leaves of this plant may promote skin health when applied topically in a cream. The German Commission E has approved black walnut leaves for topical use for relieving skin inflammation and excessive perspiration. [2]

Because of the observed cytotoxic and anticancer effects of juglone and plumbagin, black walnut has been proposed as a chemotherapy agent. [3] Some preliminary evidence suggests that extracts from this nut can prevent or slow the growth of various cancer types. [4]

These results have been observed in in vitro studies using human cancer cells. However, no trials in human patients have occurred yet; clinical research is needed in this area.

Current research is also exploring possible benefits for cardiovascular disease, metabolic syndrome, and Alzheimer’s disease. [3] However, there are currently no published studies evaluating this natural health product for any medical uses in human patients.

Clinical research is needed to determine the therapeutic efficacy of black walnut extract for any health problems.

Black walnut extract is regulated as a dietary supplement and the FDA has not approved it as a drug to prevent or treat any medical conditions.

If you are interested in learning more about this supplement, consult with a doctor to detemerine whether it is right for your needs.

How to Take Black Walnuts

Black walnuts are popular in many foods, especially in Europe, Canada and the US. They are used in meat dishes, ice cream, candy, salads, pasta dishes, and more. [1]

According to Organic Facts, “You can either consume black walnuts directly or use the walnut husk ground into powder; black walnut oil would be very difficult to extract and this is not the common usage of this particular herbal remedy.” [1]

NMCD reports that there are currently over 550 different supplements that contain black walnut extract. When possible, choose products that are organic, non-GMO and free of contaminants and fillers. [3]

Supplements come in a variety of forms including tablets, capsules, bulk powder, liquid extracts, and tinctures. Supplements are almost exclusively made from the walnut hulls and not the walnuts.

Black Walnut Dosage

According to the NMCD, “Based on secondary sources, a typical dose of black walnut hull is 1,000mg, three times daily with water, not to exceed six weeks.” [3]

Oral pills, capsules and tablets are made with powdered black walnut. They are typically sold in serving sizes of between 500 mg – 1,000 mg.

Liquid tinctures are also available. One product, Biophix Fresh Green Black Walnut Complex, contains green black walnut hulls, wormwood (Artemisia absinthium) and clove buds (Syzgium aromaticum).

Different products may contain different concentrations of active ingredients. It is recommended to the follow dosing instructions on any specific product you purchase or speak with your doctor for dosage guidelines.

This supplement is sometimes combined with other ingredients to enhance its efficacy. Some popular combinations include echinacea, garlic extract, cranberry fruit, and Pau D’ Arco bark.

Supplement Safety, Side Effects, and Interactions

The Natural Medicines Comprehensive Database rates black walnut as Possibly Safe when used orally and appropriately, short term. It is rated as Possibly Unsafe when used topically because of its juglone content.

Black walnut is also rated Possibly Unsafe when used topically during pregnancy or while breast-feeding. Safety information regarding oral use in these groups is lacking. It is recommended to avoid use.

Black walnut supplements are typically well tolerated when taken at appropriate dosages in the short term but may cause stomach upset.

Because of the high tannin content, there is concern that extended use could increase the risk for oral and/or esophageal cancer, liver damage, or kidney damage. Only short-term use of less than 6 weeks at a time is recommended for this reason.

Black walnut products may cause dermatitis or skin irritation and inflammation when used topically.

The high tannin content in black walnut may interfere with absorption of some drugs and supplements. It is not recommended to take this extract with other supplements that also contain tannins due to potentially high accumulation levels.

Discontinue using this and other dietary supplements at least two weeks prior to any scheduled surgery, unless instructed otherwise by your physician.

It is recommended that you speak with your doctor before beginning any new supplements. Your doctor will be able to determine if black walnut supplements are appropriate for you.

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