Among other things, adaptogenic herbs can modulate the horse’s response to stress and help regulate the immune system.

Many horses today are living with overwhelming stress: emotional, physical, and spiritual. If stress continues unabated, it leads to processes in the body that can ultimately result in immune system dysfunction. This article looks at how a category of herbs called adaptogens can help horses whose immune function has been negatively impacted by stress.


Emotional stress in the form of confinement stabling, with minimal turnout and little to no social interaction, creates boredom and frustration, often resulting in anger and phobias. Additionally, horses often have little to no ability to graze “healthful” weeds because paddocks have become grass monocultures. Physical stress arises in the form of long periods of inactivity interspersed with intense periods of work. Then there are the ingested, injected, and topical toxins, including vaccines, pesticides, glycophosphates, herbicides, organophosphates, GMOs, and pseudo-estrogens from plastics. Owner stress can also translocate to horses, creating a form of spiritual stress to the equine.1


The common factor in any type of stress is an increase in resting cortisol levels. Stress is managed by two different physiological systems: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal-SAS system. When stress is perceived in the limbicsystem within the brain, the hypothalamus releases corticotrophin-releasing hormone. This stimulates the release of ACTH from the pituitary, which in turn stimulates the release of glucocorticoids from the adrenal cortex.


The sympathetic nervous system stimulates the release of catecholamines — adrenaline from the adrenal gland — and the noradrenalin-fight or flight response. The induced behavioral, biochemical, and physiological changes are referred to as the stress response. This stress response prepares the body for physical exertion by stimulating the heart, increasing blood flow to the muscles and brain, raising blood pressure, and liberating sugar stored in the liver. The body is prepared for fight or flight, and is given the energy to meet the challenge with the release of cortisol and adrenaline. If the reaction is too strong, blood pressure surges, the excess cortical creates a catabolic state with cell and muscle destruction and gastric ulcers, and increases glucose levels. If the stresses continue, the body enters a state where it resists the stress and tries to return to normal homeostasis. In this stage, the cortisol level is high, and the DHEA level drops. Ultimately, an exhaustion state is entered. Energy levels are depleted, and we find fatigue and immune system dysfunction.


Adrenal dysfunction is caused by:

  1. Excess or deficiency of cortisol, DEAH, ACTH, and/or CRH
  2. Hormone imbalance
  3. Loss of sensitivity of the hypothalamus and pituitary to the normal controlling aspects of these hormones
  4. General energy depletion.

Our equines face several conditions caused by immune system dysfunction:

  • Hypofunction — seen in cancerous conditions or post-Lyme neuropathies
  • Hyperfunction — seen in conditions like chronic obstructive pulmonary disease (COPD), trigeminal neuralgias, or recurrent uveitis.


Adaptogens are a relatively new class of herbal medicines. Dr. Nikolai Lazarev conducted pioneering work in this field when he started researching botanical chemical compounds that could help promote health by decreasing the negative effects of acute or chronic stress. In the 1960s, Israel Brekhmann continued research into these botanicals. Adaptogens must fit three criteria:2

  1. They are non-toxic even if used long term.
  2. They produce a nonspecific state of resistance to stress.
  3. They create a normalizing influence on the animal’s physiology by modulating hyper and hypo functions. Adaptogens must be shown to work by re-regulating the two master control systems in the body — the HPA axis and the SAS.

There is some overlap of herbs that are considered Chinese Qi tonics and Ayurvedic rasayana herbs, but only those that work through the HPA axis or the SAS are adaptogens.

Adaptogens can modulate the horse’s response to stress and help regulate the interconnected endocrine, immune, and nervous systems; provide an anabolic effect; protect energy resources from depletion; enhance the action of cellular ATP; stimulate the mitochondria; and at a cellular level, act as strong antioxidants. Metabolically, they prevent the formation and acumination of beta-lipo-proteins, substances that block key enzymes responsible for transforming glucose. In short, they improve the capacity and sustaining power of the body to adapt to stress and minimize its effects.


While adaptogens can support and modulate the immune system, and enhance humoral and cellular immunity with concurrent anti-inflammatory and antiallergic activity, each herb has its own unique characteristics and energetics. This demands knowledge of each botanical medicine, knowing their specific indications so they can be used to their fullest potential. Any herb must be prescribed based on the patient’s energetic diagnosis. In general, all the herbs, except wild American Ginseng (which is endangered — see below), can be given to equines at two to three times the labelled human dose.

American Ginseng (Panax quinquefoliumm) is a truly amazing herb — but it is severely endangered in the wild. Never purchase wild-crafted American Ginseng; only purchase from a sustainably cultivated source.

This herb is sweet, bitter, slightly warm or slightly cooling due to its moistening effect. It will replenish lost fluids caused from fighting chronic heat toxins such as Lyme or viral infections. Lung and Spleen meridian organs are primarily affected.

The root is the part used to make medicine. It has a long history of use by Native American peoples. Interestingly, the sale of American Ginseng supported the American Revolutionary War and was the most valuable cargo to leave the NY harbor by ship.

American Ginseng is very helpful for replenishing the HPA axis and the adrenal glands. It reduces elevated cortisol levels, thereby enhancing immune function and increasing resistance to bacterial and viral pathogens. It’s beneficial for allergies and COPD as well as immune deficiency conditions and metabolic syndrome. Chinese medicine classifies American Ginseng as a Yin, Spleen and Lung Qi tonic. “It exerts a decidedly beneficial influence in exhaustion of the brain from overwork, and it is probable that its influence is as much in this direction as upon the stomach,” wrote Scudder, an 18th century herbalist.

Amla fruit or Indian Gooseberry (Phyllanthus emblica, formerly Emblica officinalis) is a plant of extraordinary importance to the Indian culture. It plays a pivotal role in health and longevity, and is a great help in treating periodic ophthalmia or moon-blindness.

Although this herb is not classified as an immune modulator, it is a probable adaptogen. This fruit is sour and sweet with a cool and drying energy, affecting the Heart, Liver, and Kidney. Amla is classified as a Blood and Yin tonic that stabilizes the small capillaries in the eye, helping with vision. It can protect the liver from drugs and viruses, restore the appetite and relieve nausea. Amla is indicated in any rheumatoid problem with oxidative damage to the connective tissue as it nourishes the blood in all tissues, repairing small capillary beds.

Ashwagandha (Withania somnifera) root is bitter, warm, and dry. It has been used widely in India for centuries, and is reputed to give one “the strength of a stallion”. It is a rasayana herb that prolongs life, stimulates the mind, and enhances vigor, and is used for many conditions such as paralysis, coughs, impaired cognitive function, asthma, and infertility.

Ashwagandha’s unique and specific use is as a calming adaptogen, and it is specific for nervous and restless exhausted horses with hypothyroid tendencies. It improves thyroid function, is a Yang tonic but also sedative, and supports sound sleep. A keynote for its use would be stalled horses that are “trashed” up from nervous restless pacing while stabled.

Ashwagandha is also beneficial for hyper and hypoimmune conditions such as sarcoids, as it has antispasmodic effects in Lyme arthralgias.

Asian Ginseng (Panax ginseng, Ren Shen) root is sweet, bitter, warm, and moist. It has a very long history of use, and is a king tonic remedy. In Chinese medicine, it supplements the five Yin organs, calming the mind and pacifying the soul, both ethereal and corporeal.

Ren Shen has many functions. It’s an immune amphoteric that  normalizes immune function; reduces excessive immune response in COPD; strongly tonifies the Yuan Qi when used for extreme collapse; tonifies the Lung and augments Qi for wheezing and shortness of breath; strengthens the Spleen and tonifies the Stomach for lethargy and lack of appetite; generates fluids and stops thirst; benefits the Heart Qi and calms the anxious spirit. This is not an herb to be used in cases of acute inflammation.

Cordyceps (Ophiocordyceps sinensis, Cordyceps militaris) is a caterpillar fungus traditionally used only for the emperor or royal family in ancient China. Today it is grown on a plant protein. It is sweet, slightly acrid, warm, and moist.

It affects the Kidney and Lung. This mushroom is indicated for conditions of deficient Kidney Yin or Yang when caused by chronic disease, excessive physical exertion, or autoimmune conditions. Cordyceps enhances aerobic capacity and cellular energy stores, and is the prime choice for drug-induced glomerulonephritis.

Codonopsis (Codonopsis pilosula, Dang Shen) root is sweet, moist, and slightly warm. It is a Qi tonic for weak, deficient, and tired individuals. It strengthens Stomach/Spleen Qi, enhancing appetite, improving digestion, building blood and increasing RBCs. Dang Shen is indicated for individuals that suffer from chronic cold-like symptoms, as it can build defensive energy (Wei Qi). It is one of the herbs used in Fu Zheng therapy, a branch of herbology designed to mitigate the ill effects of chemotherapy while simultaneously enhancing its benefits.

Eleuthero (Eleutherococcus senticosus) root and stembark are sweet, slightly bitter, and slightly warm. This herb is commonly called Siberian Ginseng. It strengthens the immune system, decreasing the incidence of upper respiratory infections and flu when under stress. Think of its use when new horses come into the barn. Eleuthero is the herb for athletes as it increases endurance and stamina, enhances mitochondrial activity, speeds recovery, and prevents immune depletion from excessive training. It’s strongly indicated for stressed athletes. This herb is easily combined with other adaptogens such as Cordyceps, Rhodiola, and Schisandra for enhancing athletic performance and improving alertness and cognitive function when under severe stress.

Note: Watch for banned herbs under competition.

Holy Basil (Ocimum tenuiflorum) is pungent, sweet, and warm (leaves are used). It is sacred to the Hindu god Vishnu, purifying the air where it dwells. It is a dopamine adrenergic agonist, helping to prevent pituitary degeneration as seen in Cushing’s disease.

Holy basil is useful in metabolic syndromes as it helps regulate blood sugar. It improves memory and enhances cerebral circulation, treating brain fogs post Lyme disease or EPM. This herb prevents increases in corticosterone levels from stress, including noise stress; helps prevent gastric ulcers; reduces pulmonary allergies; helps remove meningeal toxins; and is indicated for head shakers, and other forms of allergic rhinitis.

According to David Winston, this is one of the herbs for treating “stagnant depression”, situational depression that develops from traumatic events when the horse gets “stuck”.

If your horse faces radiation therapy for a squamous cell carcinoma, Holy Basil protects the normal cells and chromosomes against radiation damage.

Jiaogulan (Gynostemma pentaphyllum) leaves are sweet and slightly bitter, with a neutral energy. It has a long folk use in the treatment of fatigue, cold prevention, and enhancing longevity. It is a calming herb with good indication for hyper horses. If your horse is traveling, it’s commonly used for jet lag and altitude sickness (with Dang Shen).

Jiaogulan has recently been found to enhance immune system function in cancer patients, and to prevent reverse immunosuppression from chemo or radiation therapy. It increases endogenous superoxide dismutase. It decreases allergic reactions, and is indicated for allergic rhinitis and COPD. This herb enhances immune function, especially macrophage activity, T lymphocytes, and NK cells, and acts as a cancer inhibitor.

Licorice (Glycyrrhiza glabra) root has been in use since the time of Dioscorides, an ancient Greek physician. This neutral, sweet herb clears heat and dispels toxins. It minimizes the poisons from pesticides, herbicides, and pharmaceuticals, being very hepatoprotective, and alleviates symptoms arising from their toxicity. This herb will retain sodium, so is not to be used with any case of hypertension. Licorice can strengthen sinews and bones, Stomach and Spleen, and aids in the treatment of diarrhea, fatigue, gastric ulcers, and chronic coughs.

Prince Seng (Pseudostellaria heteropylla) root is sweet, slightly bitter, cool, and moist. It is considered the “Ginseng of the Lungs” as it strengthens the Lungs and Spleen, nourishing weak, dry, and damaged lung tissue. A wonderful addition in chronic COPD cases, it is also strongly indicated for improving the immune system of local mucus membranes, being a Fu Zheng herb.

Reishi (Lingzhi, Ganoderma lingzhi) is a sweet and bitter, neutral to warm mushroom. It strengthens all five viscera, tonifying Heart, Liver, Kidney, Lung Qi and Blood. It soothes the spirit and soul and has good specific indications for horses with emotional and spiritual stress, as it transforms phlegm so they can “see” things more clearly. Reishi is strongly hepatoprotective and is indicated for any allergic tendencies, allergic rhinitis, ocular issues, and senile heart. “It is the thing that Immortals live on,” wrote Li Zhi Shen in 1593.

Rhaponticum (Rhaponticum carthamoides) Root is bitter, slightly sweet, resinous, cool, and slightly dry. It grows in southern and eastern Siberia, and was traditionally used for respiratory, liver, and kidney disease as well as fevers and sore throats.

This herb has been found to enhance recuperation after illness, relieve tiredness, and promote physical and mental performance. It is also indicated for athletic stress; it improves performance, endurance, and recovery from intensive training. Rhaponticum also promotes the building of muscle tissues; enhances the excretion of uric and lactic acid; and stimulates blood flow to the muscles and brain. Workers report an increased resistance to cold, heat, noise, and lack of sleep.

Rhaponticum enhances immune function, helps stabilize blood sugar levels, and prevents hemolytic anemia, as well as anemia from chemo- therapy and radiation treatments.

Rhodiola (Rhodiola rosea), also called Arctic rose, grows in northern circumpolar regions. It is sweet, slightly bitter, spicy, cool, and dry. This herb enhances alertness, reduces fatigue, improves memory, relieves depression, and is indicated for post-Lyme brain fog, and emotional and spiritual stress. It aids recovery from head trauma. Rhodiola relieves muscle spasms and stiffness while improving athletic performance and endurance, and promotes the building of muscular tissue.

Schisandra (Schisandra chinensis) is a Chinese herb that is sour, sweet, salty, bitter, pungent, warm and dry — it contains all five flavors. It benefits all five Yin organs: Liver, Kidney, Lung, Heart, and Spleen. Schisandra is used to astringe the Jing, and control leakages like diarrhea, frequent urination, excessive vaginal discharge, and spontaneous sweating as seen in Cushing’s disease. It enhances reflexes, work performance, alertness, and mental activity, yet is also calming and helps relieve anxiety and stress-induced asthma or palpitations, hence it’s well indicated for COPD.

This herb is helpful for hyperactive immune responses, allergies, or hypo conditions, such as Lyme arthralgias and any allergic condition. It is also a hepatoprotective agent and prevents chemical stress.

Shatavari (Asparagus racemosus) root is sweet, bitter, warm, and moist. It is a powerful herb used to enhance physical strength, maintain youthfulness, improve memory and intelligence. It is a female reproductive tonic, and will increase milk flow.

In summary, adaptogens are powerful agents that support and normalize our horses’ immune systems. However, they should be used with their energetics and specific indications in mind, and included in a well-thought-out formula.



Dr. Cynthia Lankenau received her DVM from Cornell University in 1981, and started studying alternative modalities in 1992. She is certified with the IVAS, AVCA and AHV, and in Chinese Herbal Medicine through the Chi Institute and CIVT. She is a registered herbalist through the American Herbal Guild and is currently working on CIVT’s Western Graduate Herbal program. She is Past President of the Veterinary Botanical Medicine Association, and owns a private integrative mixed practice.


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