Walnut Hull
Medicinal Part: the green hull
Constituents
Tannins (galloylglucose, ellagitannins)
Naphthalene derivatives; the fresh leaves and green fruit peels contain 1,4,5- tryhydroxynaphthalene-4- beta-D- glucoside, which is transformed into juglone through bruising or drying. Juglone polymerizes readily into yellow or brown products (that stain the skin), so there can be hardly any juglone present in the drug itself.
Flavonoids: including, among others, hyperoside, quercitrin
Black walnut hulls are a strong natural source of iodine
Effects
Astringent and fungistatic. The astringent effect is due to the tannins. The jugalone content in the hulls has been linked to mutagenic action. The topical use of the hull has been linked to cancer of the tongue and leukoplakia of the lips.The antifungal effect is due to juglone and the volatile oils. Astringent properties can be soothing to weeping lesions when used as compresses.
Uses
Approved by Commission E
- Inflammation of the skin
- Excessive perspiration
Externally, used for mild, superficial inflammation of the skin and excessive perspiration. Internally it is used for gastrointestinal catarrh and as a blood purifier.
Chinese medicine: used to treat asthma, lumbago, beriberi, impotence and constipation
Ayurveda: used for alternating rheumatic complaints,
- Black Walnut Hull may help to lower blood pressure and serum cholesterol levels and is believed to burn up toxins and fatty materials while balancing blood sugar levels.
- The tannins in Black Walnut Hull (and leaves) possess an astringent quality that is thought to shrink the sweat glands and reduce excessive sweating. The herb is said to help control menorrhagia, the excessive loss of blood during periods. It is also used to control diarrhea.
- Black Walnut Hull is considered a tonic that aids digestion and the intestinal system. It helps to relieve colic, heartburn and flatulence. As a cholagogue, it stimulates the flow of bile into the intestines and is thought to ease bilious colic and pain in the spleen.”
Walnut extract is made from the fresh green shells of English walnut Juglans regia. The aqueous extract has been shown to be particularly effective as a self-tanning sunscreen agent. Its most important component is juglone (5-hydroxy-1,4-naphthoquinone), a naphthol closely related to lawsone (2-hydroxy-1,4-naphthoquinone). Juglone is known to react with the keratin proteins present in the skin to form sclerojuglonic compounds. These are colored and have UV protection properties.
Anitha, T.; Medicinal Plants Used in Skin Protection; Asian Journal of Pharmaceutical and Clinical Research: Vol5. Sup , 2012
During the Chernobyl nuclear disaster the areas in the fallout zone ran out of potassium iodide and sea weed sources of iodine. They used black walnut tincture as an iodine supplement by painting people's knee skin with it. It was effective in preventing radiation poisoning of the thyroid in those treated with it.
Comparison of the Effects of Juglans nigra Green Husk and Clotrimazole on Candida albicans in Rats
Side Effects
Preparation & Dose
Glycerite
Dried hulls (1:6); 1-5 ml (0.2-1 tsp) 3 times daily
Capsules or bulk powder
1,000 - 2,000 mg, 3 times a day
Tincture:
Fresh hulls (1:2, 95% alcohol); dried hulls (1:5, 50% alcohol) 5 drops to 3 ml (0.6 tsp) 3 times daily
Another Tincture method:
The green hull is the part that herbalists are most interested in. It’s important when making a black walnut tincture to use the hulls before they turn black or become bruised. So choose walnuts that are a little under-ripe for best results.
10 to 12 black walnut hulls
3 to 4 cups of 40% or higher proof vodka
1 quart jar
5 amber glass bottles with dropper lids
Fill a quart jar with fresh black walnut hulls. Pour 40% vodka over them. Generally an herbalist would use an alcohol of at least 50% or 100 proof for this preparation, but where I live you can’t easily find vodka with a higher alcohol percentage. The tincture is still strong enough even with a lower alcohol percentage.
Cap tightly. Label and date the jar. Shake the jar once a day or as often as you think of it. After 6 weeks, strain the jar contents, reserving the liquid. Press the spent walnut hulls with a potato ricer or other press, to capture as much of the tincture as possible. Discard the walnut hulls. Pour the completed tincture into amber glass bottles. Cap with a dropper lid.
Hilda Clark's Recipe uses just one large walnut with the green hull.
Label and date. The tincture will be good for years. Iodine is very stable.
Black walnut hulls are safe for occasional use of up to 2 weeks at a time
The normal dosage of the tincture is very low, since the herbal remedy is so strong. 15 drops can be taken in water, 3 times a day. To use it as an iodine supplement it’s just as effective to paint the skin with it as it is to take it orally.
Removing Stains
Processing walnut hulls can stain your hands if you aren't wearing gloves. Here are a few ways to remove it:
1. Oil Dissolution (best for fresh stains)
Juglone is oil‑soluble, so oils help dissolve it.
- Olive, coconut, or vegetable oil
- Rub in for 5–10 minutes
- Wash with warm water + soap This works best immediately after exposure.
Baking soda + liquid soap paste
- Mix equal parts
- Scrub gently 2–3 minutes
- Rinse This combines surfactant action with safe exfoliation.
Salt scrub
- Wet skin
- Sprinkle coarse salt
- Rub gently Salt loosens pigment bonds and removes stained cells.
Tannins and juglone respond to acids.
Lemon juice or white vinegar
- Apply generously
- Rub 1–2 minutes
- Rinse Acids disrupt pigment adhesion to skin proteins.
Hydrogen Peroxide (lightens oxidized pigment)
- Use low concentration (3%)
- Apply briefly, rinse Acts as a mild bleach to lighten the stain. Do not overuse — can irritate skin.
Mechanical Exfoliation Options
If stains are very dark or several days old:
- Pumice stone (gentle use only)
- Sugar scrub
- Repeated washing with abrasive soaps (mechanic’s soap)
These remove stained outer skin layers
Culinary Uses of Green Walnut Hull (the outer husk)
The green hull is the fleshy outer covering of the walnut before it dries and turns black. It is not eaten directly, but it is a powerful ingredient for infusions, extracts, pickles, and dyes.
1. Nocino-style liqueur (black walnut liqueur)
Green hulls are the defining ingredient in:
- Nocino (Italian-style walnut liqueur)
- American black walnut bitters
- Ozark-style walnut cordial
The hulls contribute:
- Aromatic bitterness
- Deep color
- Resinous, spicy notes
- A warming, almost clove-like complexity
2. Pickled green walnuts
A traditional British preparation:
- Whole immature walnuts (with hull) are brined, then pickled
- Flavor becomes savory, umami, almost Worcestershire-like
- Used with cheese, charcuterie, or roasted meats
3. Syrups and bitters
Green hulls can be infused into:
- Simple syrup
- Honey
- Vinegar
- Alcohol tinctures
These create cocktail bitters, wild bitters tonics, or dark syrups for autumn desserts.
4. Natural dye
Culinary-adjacent but important:
- Green hulls produce rich brown dyes
- Used for textiles, inks, and traditional craft
- Not edible, but part of the plant’s cultural use
5. Herbal preparations
Not culinary, but relevant:
- Hulls are used in tinctures for their strong antimicrobial properties
- These are not food uses, but they appear in ethnobotanical records
Safety & Handling Notes
- Green hulls stain everything (hands, counters, clothing)
- Hulls contain juglone, which is not harmful in culinary infusions but should not be eaten directly
- Mature black hulls (the dark, decomposing ones) are not used in food preparations
- Always use immature green walnuts harvested before the shell hardens