The science of nettle as a tonic – a plant used traditionally to combat mental fatigue and restore our spring vitality.

The taste and tonic action of fresh spring nettle tea and soup (scroll down for recipe) should overcome reluctance to use this weed with a sting as a medicinal plant. Its use since ancient times as a tonic comes with a series of lab studies showing how it stimulates mood and memory and works as a neuro-regenerative.

Overwhelmed, stretched to the limit and pounded by sensory overload?

For many, mental and physical fatigue goes with today’s lifestyle and expresses itself through stress, irritability or altered mood and also by physical signs like headaches, gastro-intestinal problems or fatigue. Fortunately, the right plant can boost mental and physical energy by helping to strengthen overstressed body systems. Though this plant may come to mind more often while weeding, it makes a surprisingly tasty fresh botanical tea and then there is growing evidence behind its use as a restorative tonic.

Plants can be energisers that reduce fatigue, tonics that strengthen relevant body systems, or adaptogens that restore stress systems that go out of kilter – and yes there is science behind how plants act as adaptogens, but not enough space to go into here. Few energising plants have been tested in human trials for mental fatigue, because apart from chronic fatigue syndrome (ME, myalgic encephalopathy), multiple sclerosis and to a lesser extent depression, mental fatigue is not recognised as a symptom in Western mainstream medicine. Lab-based scientific studies however do show the impact of energiser plants, or their chemical ingredients, on the brain and nervous system.

Around the world, of many core energisers, two are traditional medicinal plants with origins in China – astragalus and ginkgo; two European plants, one sweet and the other with a sting – liquorice and nettle; and two the Asian and Indian spice ginger and fiery vegetable garlic, as well as the celebrated superfood green tea. Today we focus on the stinging nettle.

Urtica urens

About the plant. Originating from Russia, Scandinavia, Europe and northern Africa, nettle grows to 1m, much to the annoyance of most gardeners and farmers. This annual has heart-shaped leaves and green flowers (which are incomplete, with stamens on male and pistils on female flowers). The larger nettle U. dioica has similar health uses.

History and folklore The Latin name uro translates as “I burn”. Roman soldiers allegedly brought nettle (U. pilulifera) to Britain to chafe their limbs in the cold, the sting stimulating blood supply. Recommended for several ailments by Dioscorides according to J.H. Clarke who writes in A Dictionary of Practical Materia Medica, “Being eaten, as Dioscorides saith, boiled with periwinkles, it maketh the body soluble, doing it by a kind of cleansing faculty.” The Greek philosopher Platonicus (c.400AD) said it would “treat symptoms of feeling cold after being burnt” (burnt is now thought to mean being shocked). Recognised today as a stimulating tonic, it’s claimed to be a restorative tonic for stressed adrenals. Some medical herbalists say it’s particularly useful for those suffering from severe “burnout” that results from profound fatigue, brain fog, chronic pain and feelings of depression and intense anxiety.

What scientists say. In humans. Clinical trials, not yet focused on mental states, have confirmed other traditional uses such as reducing blood lipids, joint pain, infections and oxidative stress in diabetics. In the lab. Reduces oxidative stress in exercise-stressed models and depressive behaviour, as well as enhancing cognitive function. Acts on the brain’s memory signal (acetylcholine receptors) and in models of encephalopathy (brain disease) nettle increases the number of nerve cells in the memory area (hippocampus) and also the number of cells (glia) which support nerve cells in the brain. Also antibiotic, anti-inflammatory and neuroprotective in cell models.

Key ingredients Flavonol glycosides (like rutin), carotenoids and histamine, serotonin and acetylcholine as well as formic acid in stinging hairs and the coumarin scopolecin in root. High in vitamin C and K, calcium, potassium and other minerals.

How to take it For internal use, pick leaves before flowering to make tea (5–12g fresh or 2-6g dried daily / 240ml water). Fresh leaves also make pressed juice, salads (in early spring before sting develops), soup, pesto, pasta (young shoots cooked taste like spinach) and puddings, as well as beer, wine and liqueur. Tinctures, capsules and dried root also used. Can be used in skin and hair creams (externally) for pain such as arthritic where the stinging is part of the treatment.

CAUTION Always consult a registered medical herbalist before taking any plant at a medicinal level, inform your health care provider if you are taking medication or have any medical condition and do not stop taking prescribed medication. Be sure of the identity of your plant and take only at the recommended dose.

Safety. Apart from the hazard of being stung, or if you’re allergic to nettle stings, nettle is regarded as free of contraindications, though it is advised to abstain from topical use if breastfeeding. Listed in the US pharmacopeia and freely available as a dietary supplement.

Mzid, Ben Khedir, Ben Salem, Regaieg & Rebai. Antioxidant and antimicrobial activities of ethanol and aqueous extracts from Urtica urens. In Pharm Biol. 2017 Dec;55(1):775-781. doi: 10.1080/13880209.2016.1275025.
Patel, Sita Sharan; Udayabanu, Malairaman (2014): ‘Urtica dioica extract attenuates depressive like behavior and associative memory dysfunction in dexamethasone induced diabetic mice.’ In Metabolic Brain Disease 29 (1), pp.121–130. DOI: 10.1007/s11011-014-9480-0.
Toldy, Anna; Atalay, Mustafa; Stadler, Krisztián; Sasvári, Mária et al. (2009): ‘The beneficial effects of nettle supplementation and exercise on brain lesion and memory in rat.’ In The Journal of Nutritional Biochemistry 20 (12), pp.974–81. DOI: 10.1016/j.jnutbio.2008.09.001.

Nettle and wild garlic soup – a physic garden spring tonic
Heat a knob of butter or dollop of olive/ coconut oil in a large saucepan over a medium heat. Add a finely chopped onion, carrot and celery and soften for 5 mins. Add 2-3 sliced potatoes, salt and pepper and cook for 10 minutes. Add 1-2 tsp freshly chopped or dried turmeric and fresh ginger and 1L veg or other stock and cook for a further 10-15 minutes until potatoes are soft. Add big bunch (400g) of chopped nettle tips and garlic leaves to pan and cook for a further 5 mins. Remove from heat, liquidize, add freshly ground pepper to taste. Serve with cream, cream fraiche or parmesan and sprinkled garlic flowers and chopped leaves.

This is taken from Botanical Brain Balms, Filbert Press. Available buy at Dilston Physic Garden and book shops.