The Surprising Superpowers of Nettle Seed
by Monica Wilde MSc FLS
Research herbalist & forager
Nettle Urtica dioica is a plant that needs little introduction. As children we quickly learnt to recognise them just so that we could avoid their itchy burning sting. They are part of our linguistic culture too. To nettle some one is to annoy them; to grasp the nettle – face up to an unpleasant situation; nettle rash (urticaria) – a hot itchy skin condition; to urticate – cause a stinging or prickling sensation; and we even have a special word for whipping ourselves with nettles – urtification! Nettle is fairly well-known as a highly nutritious wild vegetable. Many people have tried nettle and wild garlic soup – a foraging classic – and nettle leaf tea is widely available. However, the use of nettle seed is still fairly uncommon.
As the days lengthen, the female nettle produces inconspicuous flowers quickly followed by green seed, drooping like heavily-laden catkins from the upper third of the plant. Over the summer the seed ripens and thickens. It’s harvested when still green before it starts to dry out and turn brown. It is crunchy and full of oil high in polyunsaturated fatty acids – predominantly linoleic as well as linolenic, palmitic, oleic and stearic acids. Our bodies use linoleic and linolenic acids to make the important essential fatty acids omega 3 and omega 6.
To harvest nettle seed, I cut off the top third of each nettle and dry them on a sheet or brown paper in the sunshine, turning them occasionally until the leaves feel crisp. Then, wearing rubber gloves, I rub the seed off into a bowl. The green seed is quickly separated from any stray leaves or stems by sifting it through a standard steel mesh kitchen sieve. If you’re rubbing a lot of seed through a sieve it’s a good idea to wear a paper mask as airborne seed dust can be itchy. For nettle seed that I plan to feed to other people, I take the precaution of toasting it in a dry frying pan. The heat dissolves any stray ‘crystal hairs’ (cystoliths) and brings out their nutty taste, a little like toasted hempseed.
Nettle seed tastes delicious. It can be substituted for poppy seed in crackers, oatcakes, bread or sprinkled with chopped nuts into salads. Nettle seed will give you an energy boost and help to put you in a cheerful mood. For stimulating health benefits, take one to two spoons of fresh green or dried nettle seed a day (a standard heaped tablespoon is about 5 grams). You can chew up to 20 grams a day but many people find that just a teaspoonful is all they need. Try mixing them into yoghurt, a smoothie or add them to overnight oats. Don’t try adding them to juices though as they float and are hard to drink! I also sometimes grind them and mix them with peanut butter or honey. Spread on toast or made into protein snack bars, this is another delicious way of eating them. They also often end up being ground with seaweed, spices and salt as a seasoning.
Crush the seeds in a pestle and mortar, then infuse them in sunflower oil in a warm place for a week or two. This green oil makes a nice healthy salad oil or can be used with essential oils as an anti-inflammatory liniment for arthritic joints. In the past, horse traders would feed nettle seed to horses a few weeks before selling them. It helped the old lags become sprightly again with high spirits and shiny coats. Victor Hugo in Les Miserables confirmed that “the seed of the nettle mingled with fodder imparts a gloss to the coats of animals” and the seeds were once used to fatten up fowl.
Nettle seed is considered a Western adaptogen herb that supports the adrenal glands and endocrine system. This is why in herbal medicine it is used as a tonic for fatigue and adrenal exhaustion; for people who are burnt-out, run down and low in energy, zest for life and libido. For those interested in biochemistry, the ‘feel-good’ factor from eating raw, dried nettle seeds is caused by the neurotransmitters acetylcholine and serotonin, closely followed by choline and histamine.
Acetylcholine binds to the mood receptors in our brains. It stimulates the autonomic nervous system, improves mood and heightens sensory perception, attention span, vigilance and intuition. Acetylcholine disruption may be a primary cause of depression. Serotonin acts on the central nervous system. It regulates mood, appetite and sleep, influences memory and learning. It is serotonin, along with histamine and formic acid, in nettle spines that causes the pain when you pick them! Incidentally, acetylcholine in nettle venom may well explain why the ancient practice of urtification for pain relief actually works! Nettle seeds also raise dopamine levels, creating pleasurable feelings.
Both the roots and seeds of nettle contain a lectin called Urtica dioica agglutinin (UDA). We’re not yet sure how much the seed contains but UDA is interesting because it contains a unique pattern of T-cell and cytokine activation, known as superantigen activity. In plain-speak, this means that it supercharges the body’s natural defences and immune system without, as other studies show, raising pro-inflammatory cytokines.
Nowadays medical herbalists mainly use nettle seed to increase energy, as an anti-inflammatory and as a highly effective kidney trophorestorative. It slows down renal failure, evidenced by increased kidney glomerular function and lowered serum creatine levels. Modern clinical studies have shown that it also protects the liver, repairing it and restoring liver function after oxidative damage. Another macronutrient found in nettle seed called choline (a component of lecithin vital to liver function). Choline is sometimes used to treat liver cirrhosis and hepatitis. Studies have also shown that it is indeed anti-inflammatory and will soothe colitis (inflammation of the colon).
Nettle seed can be made into a tincture. In its most basic form a tincture is just an alcoholic extract. In the 16th century nettle seed was crushed and then soaked in wine, you can also infuse the crushed seeds in vinegar. Today, homemade tinctures can be made using 40% strength vodka at a ratio of 1 part of seed to 5 parts of vodka by volume. The seed must be crushed first and soaked in the vodka for up to 3 weeks before straining off. At this strength the usual dose is no more than 2 ml taken up to 4 times a day.
When added to herbal blends with nourishing nervines such as wild oat tops, it can be used to raise low mood – in particular winter blues or seasonal affective disorder (SAD). Try combining it with cleavers and seaweeds for slow metabolic rate as in the 19th century the powdered seeds were “considered a cure for goitre and efficacious in reducing excessive corpulency” (hypothyroidism). Culpeper (1616-1654) also claimed that “the seed being drank, is a remedy against the stinging of venomous creatures, the biting of mad dogs, the poisonous qualities of hemlock, henbane, nightshade, mandrake, or other such like herbs that stupefy or dull the senses” but I have yet to find supporting evidence of that claim. In the 18th century, Elizabeth Blackwell recommended it for “coughs, shortness of breath and obstructions of the lungs” and it had a history of use in consumption (pulmonary tuberculosis). In Europe it was used to restore libido and sexual energy, and the pressed oil burned in Egyptian lamps.
One note of caution: be careful when eating nettle seed not to exceed 30 grams a day. It can be over-stimulating and, like an amphetamine, prevent you from sleeping (although some people do experiment with nettle seed recreationally). A large 250ml cup of nettle seed tea (boiled fresh nettle seed in a 1:12 ratio (25 grams to 300 ml water) may keep you wide awake for several days!
So next time that you pass a derelict building site, jump a country ditch or take out the compost, watch out for the nettles and take a second look at this remarkable plant.
The Surprising Superpowers of Nettle Seed
6 Evidence-Based Benefits of Stinging Nettle
Stinging nettle (Urtica dioica) has been a staple in herbal medicine since ancient times.
Ancient Egyptians used stinging nettle to treat arthritis and lower back pain, while Roman troops rubbed it on themselves to help stay warm (1).
Its scientific name, Urtica dioica, comes from the Latin word uro, which means “to burn,” because its leaves can cause a temporary burning sensation upon contact.
The leaves have hair-like structures that sting and also produce itching, redness and swelling ( 2 ).
However, once it is processed into a supplement, dried, freeze-dried or cooked, stinging nettle can be safely consumed. Studies link it to a number of potential health benefits.
Here are 6 evidence-based benefits of stinging nettle.
Stinging nettle’s leaves and root provide a wide variety of nutrients, including (1):
- Vitamins: Vitamins A, C and K, as well as several B vitamins
- Minerals: Calcium, iron, magnesium, phosphorus, potassium and sodium
- Fats: Linoleic acid, linolenic acid, palmitic acid, stearic acid and oleic acid
- Amino acids: All of the essential amino acids
- Polyphenols: Kaempferol, quercetin, caffeic acid, coumarins and other flavonoids
- Pigments: Beta-carotene, lutein, luteoxanthin and other carotenoids
What’s more, many of these nutrients act as antioxidants inside your body.
Antioxidants are molecules that help defend your cells against damage from free radicals. Damage caused by free radicals is linked to aging, as well as cancer and other harmful diseases ( 3 ).
Studies indicate that stinging nettle extract can raise blood antioxidant levels ( 4 , 5 ).
Summary Stinging nettle offers a variety of vitamins, minerals, fatty acids, amino acids, polyphenols and pigments — many of which also act as antioxidants inside your body.
Inflammation is your body’s way of healing itself and fighting infections.
However, chronic inflammation can inflict significant harm ( 6 ).
Stinging nettle harbors a variety of compounds that may reduce inflammation.
In animal and test-tube studies, stinging nettle reduced levels of multiple inflammatory hormones by interfering with their production ( 7 , 8 ).
In human studies, applying a stinging nettle cream or consuming stinging nettle products appears to relieve inflammatory conditions, such as arthritis.
For instance, in one 27-person study, applying a stinging nettle cream onto arthritis-affected areas significantly reduced pain, compared to a placebo treatment ( 9 ).
In another study, taking a supplement that contained stinging nettle extract significantly reduced arthritis pain. Additionally, participants felt they could reduce their dose of anti-inflammatory pain relievers because of this capsule ( 10 ).
That said, research is insufficient to recommend stinging nettle as an anti-inflammatory treatment. More human studies are needed.
Summary Stinging nettle may help suppress inflammation, which in turn could aid inflammatory conditions, including arthritis, but more research is needed.
Up to 50% of men aged 51 and older have an enlarged prostate gland ( 11 ).
An enlarged prostate is commonly called benign prostatic hyperplasia (BPH). Scientists aren’t sure what causes BPH, but it can lead to significant discomfort during urination.
Interestingly, a few studies suggest that stinging nettle may help treat BPH.
Animal research reveals that this powerful plant may prevent the conversion of testosterone into dihydrotestosterone — a more powerful form of testosterone ( 12 ).
Stopping this conversion can help reduce prostate size ( 13 ).
Studies in people with BPH demonstrate that stinging nettle extracts help treat short- and long-term urination problems — without side effects ( 14 , 15 ).
However, it’s unclear how effective stinging nettle is compared to conventional treatments.
Summary Stinging nettle may help reduce prostate size and treat symptoms of an enlarged prostate gland in men with BPH.
Hay fever is an allergy that involves inflammation in the lining of your nose.
Stinging nettle is viewed as a promising natural treatment for hay fever.
Test-tube research shows that stinging nettle extracts can inhibit inflammation that can trigger seasonal allergies ( 16 ).
This includes blocking histamine receptors and stopping immune cells from releasing chemicals that trigger allergy symptoms ( 16 ).
However, human studies note that stinging nettle is equal to or only slightly better at treating hay fever than a placebo ( 17 , 18 ).
While this plant may prove a promising natural remedy for hay fever symptoms, more long-term human studies are needed.
Summary Stinging nettle may reduce hay fever symptoms. Yet, some research indicates that it may not be much more effective than a placebo. More studies are needed on stinging nettle’s effects on hay fever.
Approximately one in three American adults has high blood pressure ( 19 ).
High blood pressure is a serious health concern because it puts you at risk of heart disease and strokes, which are among the leading causes of death worldwide ( 20 ).
Stinging nettle was traditionally used to treat high blood pressure ( 21 ).
Animal and test-tube studies illustrate that it may help lower blood pressure in several ways.
For one, it may stimulate nitric oxide production, which acts as a vasodilator. Vasodilators relax the muscles of your blood vessels, helping them widen ( 21 , 22 ).
In addition, stinging nettle has compounds that may act as calcium channel blockers, which relax your heart by reducing the force of contractions ( 21 , 23 ).
In animal studies, stinging nettle has been shown to lower blood pressure levels while raising the heart’s antioxidant defenses ( 24 , 25 ).
However, stinging nettle’s effects on blood pressure in humans are still unclear. Additional human studies are needed before recommendations can be made.
Summary Stinging nettle may help lower blood pressure by allowing your blood vessels to relax and reducing the force of your heart’s contractions. Yet, more human studies are needed to confirm these effects.
Both human and animal studies link stinging nettle to lower blood sugar levels ( 26 , 27 , 28 , 29 , 30 ).
In fact, this plant contains compounds that may mimic the effects of insulin ( 31 ).
In a three-month study in 46 people, taking 500 mg of stinging nettle extract three times daily significantly lowered blood sugar levels compared to a placebo ( 30 ).
Despite promising findings, there are still far too few human studies on stinging nettle and blood sugar control. More research is necessary.
Summary While stinging nettle may help lower blood sugar levels, more human studies are crucial before recommendations can be made.
Stinging nettle may offer other potential health benefits, including:
- Reduced bleeding: Medicines containing stinging nettle extract have been found to reduce excessive bleeding, especially after surgery ( 32 , 33 ).
- Liver health: Nettle’s antioxidant properties may protect your liver against damage by toxins, heavy metals and inflammation ( 34 , 35 ).
- Natural diuretic: This plant may help your body shed excess salt and water, which in turn could lower blood pressure temporarily. Keep in mind that these findings are from animal studies ( 31 , 36 ).
- Wound and burn healing: Applying stinging nettle creams may support wound healing, including burn wounds ( 37 , 38 , 39 ).
Summary Stinging nettle’s other potential health benefits include lessened bleeding, boosted liver health and wound healing.
Consuming dried or cooked stinging nettle is generally safe. There are few, if any, side effects.
However, be careful when handling fresh stinging nettle leaves, as their hair-like barbs can harm your skin.
These barbs can inject an array of chemicals, such as (1, 2 ):
- Formic acid
These compounds can cause rashes, bumps, hives and itchiness.
In rare cases, people may have a severe allergic reaction, which can be life-threatening.
However, these chemicals diminish as the leaves are processed, meaning that you shouldn’t experience mouth or stomach irritation when eating dried or cooked stinging nettle (1).
Pregnant women should avoid consuming stinging nettle because it may trigger uterine contractions, which can raise the risk of a miscarriage (40).
Speak to your doctor before consuming stinging nettle if you’re taking one of the following:
- Blood thinners
- Blood pressure medication
- Diuretics (water pills)
- Diabetes medication
Stinging nettle could interact with these medications. For instance, the plant’s potential diuretic effect may strengthen the impact of diuretics, which can raise your risk of dehydration.
Summary Dried or cooked stinging nettle is safe to eat for most people. However, you shouldn’t eat fresh leaves, as they may cause irritation.
Stinging nettle (Urtica dioica) has been a staple in herbal medicine since ancient times, such as to treat arthritis and back pain. Here are 6 evidence-based benefits of stinging nettle.