Niu Xi - Achyranthes root
Niu Xi - the Achyranthes root - is known in TCM primarily for its lowering effect. It directs blood and Qi specifically into the lower body and is often used for knee and back complaints.
At the same time, it strengthens the liver and kidneys, dissolves blood stasis and promotes diuresis. Its versatility as a leading herb for the lower Jiao makes it an indispensable ingredient in numerous classic recipes.
Effect from a Western perspective
Ecdysteroids and triterpene saponins are the pharmacologically relevant ingredients. The evidence comes mainly from in vitro and animal models - clinical studies on humans are limited so far.
- Bone health - Ecdysterone promotes osteoblast differentiation and inhibits osteoclast activity in cell cultures, suggesting a potential in osteoporosis (preclinical evidence)
- Inflammation inhibition - Saponins show significant anti-inflammatory effect in arthritis animal models via inhibition of NF-κB and COX-2
- Blood pressure reduction - vasodilatory effects via NO-mediated endothelial function and reduced peripheral resistance (animal models)
- Pain relief - analgesic effect comparable to low-dose NSAIDs in animal studies, presumably via central and peripheral mechanisms
- Immunomodulation - Polysaccharides stimulate macrophage activity and cytokine production in vitro
Effect from a TCM perspective
Niu Xi invigorates the blood and dissolves stasis, especially in the lower Jiao. It directs blood and fire downwards and strengthens the liver and kidney, which strengthens tendons and bones. As a guide drug, it carries the effects of other herbs into the lower body.
- Revitalize blood, release stasis - Revitalizes the blood and dissolves blood stasis, especially for menstrual pain
- Conducting blood and fire downwards - draws down rising blood and fire for headaches, nosebleeds and bleeding gums
- Strengthen the liver and kidneys - Strengthens tendons and bones for lumbar weakness and knee pain
- Drain moisture and heat - Promotes urination and drains damp heat downwards in the lower Jiao
- Messenger herb (Shǐ Yào) - directs the effect of other medicines specifically to the lower Jiao
Application & dosage
Niu Xi is most commonly used as a decoction. The standard dose is 6-15 g per day. Raw root (shēng Niú Xī) is preferred for blood stasis and heat conditions; wine-treated root (jiǔ zhì Niú Xī) strengthens the liver and kidneys more strongly and is more suitable for toning with prolonged use.
Granules and tablets are commonly used in modern preparation forms. The dosage depends on the form of application and the clinical picture - the higher dosage tends to be chosen for lumbar weakness and bone loss, and the medium dosage for heat-related ascending conditions.
Dosage forms
- Decoction (Tāng): 6-15 g, simmer for 20-30 minutes; raw root (shēng) for heat and stasis, wine-treated (jiǔ zhì) for kidney and liver tonification
- Granules (Kē Lì): 2-5 g daily, dissolved in warm water; practical for long-term use
- Tablets / capsules: 3-4 tablets of 500 mg, 2-3× daily; often in combination preparations
- Powder (Fěn): 2-4 g daily, stirred into warm water or rice wine; promotes the absorption of saponins
- Wine extract (Yào Jiǔ): Traditionally macerated in rice wine for lumbar pain and joint stiffness in the lower body
Dosage
- Standard dose Decoct: 6-15 g per day
- Light toning / long-term use: 6-9 g
- Blood stasis, moist heat, pronounced pain: 10-15 g
- Granules: 2-5 g per day
- Powder: 2-4 g per day
- Maximum dose (short-term, under supervision): 20 g
Frequent combination partners
Niu Xi often only unfolds its full effect in combination with other herbs
Combinations & formulas
- With Du Zhong and Xu Duan for lumbar and knee weakness due to liver and kidney deficiency - this combination strengthens the lower back and joints from the root.
- With Sheng Di Huang and Mu Dan Pi for blood-heat with nosebleeds or bleeding gums - Niu Xi directs the heat downwards and thus prevents the blood from rising.
- With Dang Gui and Tao Ren for blood stasis with menstrual pain or absence of menstruation - together they revitalize the blood and regulate the menstrual cycle.
- With Che Qian Zi and Mu Tong for Damp-Heat in the lower Jiao with painful micturition - Niu Xi drains Dampness downwards and supports urination.
History & Tradition
Niu Xi is already listed as an upper class herb in the Shén Nóng Běn Cǎo Jīng - an indication of its good tolerance to long-term use. The name „ox-knee" (Niú Xī) describes the conspicuous nodular thickenings on the stem nodes, which are reminiscent of the strong knees of an ox.
In the TCM doctrine of signatures, this form was interpreted as an indication of the strengthening effect on the knees and joints. Zhāng Zhòngjǐng used Niu Xi in several formulas to guide blood and qi downwards. In the Běn Cǎo Gāng Mù, Lǐ Shízhēn emphasizes that Niu Xi acts as a „messenger herb" (Shǐ Yào) - it directs the effect of other remedies specifically to the lower Jiao and thus enhances their therapeutic effect.
There are two pharmaceutically distinct species: Huái Niú Xī (Achyranthes bidentata) from the province of Hénán, which has a stronger tonic effect, and Chuān Niú Xī (Cyathula officinalis) from Sìchuān, which has a stronger blood-moving effect. The distinction is clinically relevant and is still observed today. Huái Niú Xī is one of the famous „Four Medicines from Huáiqìng" (Sì Dà Huái Yào) together with Dì Huáng, Shān Yào and Jú Huā - and has enjoyed a reputation for the highest quality for centuries.
Contraindications & caution
Contraindicated in pregnancy - the lowering and blood-moving effect can endanger the fetus and trigger premature labor. Not for heavy menstrual bleeding or metrorrhagia, as Niu Xi increases the downward flow of blood.
Caution is advised in cases of spermatorrhea and nocturnal emissions due to renal insufficiency - the lowering effect can worsen the condition. With simultaneous intake of Anticoagulants (warfarin, heparin) or Platelet aggregation inhibitors (ASA, clopidogrel), medical consultation is required as Niu Xi can also affect blood clotting. Also with Antihypertensives there is a potential risk of additive blood pressure reduction.
Botany
Achyranthes bidentata Bl. is a perennial herbaceous plant from the Amaranthaceae family (foxtail family) that grows to a height of 70-120 cm. The stems are square with characteristic nodular thickenings at the leaf bases. The opposite leaves are elliptical to lanceolate and the inconspicuous flowers are borne in terminal spikes.
The root is the medicinal raw material used - it is cylindrical, 30-60 cm long, yellowish-brown and has a slightly sweet, then bitter taste. The quality is judged by the thickness, firmness and light cross-section of the root. Pharmacologically relevant ingredients are ecdysteroids (especially ecdysterone), triterpene saponins, polysaccharides and oleanolic acid.
Occurrence
- Central China - Hénán (Huáiqìng region) as the main cultivation area for the premium variety Huái Niú Xī
- Southwest China - Sìchuān and Yúnnán for Chuān Niú Xī (Cyathula officinalis)
- Natural distribution in Japan, Korea and India at altitudes of 200-1,700 m
- Prefers sandy, well-drained loamy soil in a sunny to semi-shady location
- Today also cultivated in Southeast Asia and parts of Africa
Harvest time
- Main harvest: October to December - after the above-ground shoots have died back, when the nutrients have been completely absorbed by the roots
- Optimal time: After the first frost, when the stems turn yellow and wilt; this is when the ecdysterone and saponin content is at its highest
- Harvest age: Annual crops (cultivation from April/May), harvest in the same year in fall/winter
- Procedure: Hand digging with a spade or digging fork, as the long taproots (40-90 cm) make mechanical harvesting difficult; undamaged roots are preferred
Processing
Niu Xi is processed after harvesting in two pharmacologically different forms. The choice of processing form significantly determines the clinical effect: raw root (shēng Niú Xī) drains more strongly and moves blood, while wine-treated root (jiǔ zhì Niú Xī) tones and warms.
- Cleaning: Remove soil from fresh roots, remove fine roots and root head, wash briefly in water
- Bundling and pre-drying: Gather the roots into even bundles and leave to air dry for a few days until they are pliable but not brittle
- Final drying: Dry at max. 50 °C in a drying cabinet or in the sun until the water content is below 15 %; quality feature: flexible, non-splintery root
- Cutting: Cut the dried roots into diagonal slices 3-5 mm thick
- Raw drug (Shēng Niú Xī): Ready for use immediately after cutting; serves to move blood, dissipate heat and promote micturition
- Wine treatment (Jiǔ Zhì Niú Xī): Sprinkle the root slices with rice wine (10-20 ml per 100 g of drug), leave to soak for 30-60 minutes, then roast in a wok over a medium heat, stirring constantly, until the surface is light yellowish-brown and the smell of the wine dissipates; enhances liver and kidney tonification
- Storage: In tightly closed containers, cool and dry, at 15-25 °C; protected from moisture and light; shelf life 1-2 years
Related herbs
Herbs with similar effects and related areas of application
Comparable western herbs
- Devil's claw (Harpagophytum procumbens) - the African root is used in Western phytotherapy for joint pain and arthrosis. It is similarly used for musculoskeletal complaints and also has an anti-inflammatory and analgesic effect via iridoid glycosides.
- Willow bark (Salix alba) - the European equivalent for inflammatory joint diseases. As a natural COX inhibitor, salicin has an analgesic and anti-inflammatory effect - comparable to the NSAID-like effect of Niu Xi in animal models.
- Butcher's broom (Ruscus aculeatus) - Valued in European phytotherapy for venous insufficiency and circulatory disorders of the legs. Shares with Niu Xi the relationship to blood circulation in the lower body, has a vascular toning effect via ruscogenin.