Any horse owner with a young or nervous horse has thought that there has to be some way to help their horse deal with stress. There are a plethora of products available that aim to do just that. A number of vitamins, minerals and herbs are used to help horses relax and focus in hopes of allowing them to perform better.

Do Calming Supplements Work?

There is little research in the equine world to prove or disprove the effects of calming supplements. A few controlled studies regarding L-tryptophan show no calming effect on horses. Despite the lack of evidence form controlled studies, calming supplements are very popular and many horse trainers and owners report anecdotally that they have seen improvements in their horse’s behavior and performance when using them.

Are Calming Supplements legal?

Calming supplements should be used during training only. It is against the spirit of fair competition and the mission of the governing bodies of equine sports to use these supplements during competition. Valerian and its metabolites are prohibited during competition. Magnesium sulphate injections are prohibited as well. FEI and USEF are constantly reviewing herbal and other substances and developing testing techniques to identify those that they feel should be banned. All horse owners should make sure they are aware of all ingredients in any supplement they use and check with the governing body of their discipline if they have any questions about the legality of any ingredient.

Here is a summary of the most commonly used substances in calming supplements. Be sure to follow the dosing recommendations carefully. More is not better! In some cases liver damage, neurological abnormalities, or hemolysis can occur with use and/or misuse.

L-tryptophan is an essential amino acid (it must be supplied in the diet). It is converted to serotonin, a neurotransmitter that helps to control mood by calming anxiety, relieving depression, and aiding sleep. Most horse owners know about tryptophan due to its reputation for being the culprit for sleepiness after eating turkey at Thanksgiving. In reality, turkey has the same amount of tryptophan as other types of poultry. Low doses have been shown to actually cause excitement in horses and extremely high oral dose can product hemolysis (breakdown of red blood cells) due to conversion of tryptophan to indole (a hemolytic metabolite) in the digestive tract.

Valerian (valeriana officinalis) is a tall perennial herb with white to pinkish purple flowers. The root is used medicinally. The name valerian comes from the Latin word valare that means “well being.” Over 150 phytochemicals have been isolated from valerian root. The ones that shown to have shown to have sedative effects on the central nervous system include: valerenic acids, valepotriates, GABA, tyrosine, arginine, and glutamine. The effects of valerian root in humans are somewhat dose dependent with lower does relieving anxiety and nervousness, and higher doses aiding sleep.

Magnesium is a mineral that is essential for healthy function of almost all body systems. In the body it is found as an ion within the cells. Along with calcium, Magnesium helps to control muscle activity and nerve conduction. Calcium stimulates activity, whereas, magnesium decreases or suppresses activity. Magnesium has been found to decrease nerve excitation, decrease adrenaline secretion, decrease cortisol release, and to decrease muscle contraction by binding to intracellular ATP and breaking the actin-myosin bounds that cause muscles to contract. In very high doses magnesium acts as a laxative and can cause muscle weakness.

B vitamins are essential for converting food to fuel. They also help to stabilize lactate levels that can cause anxiety. Likely B vitamins largest impact on calming is due to its use a cofactor in the production of serotonin and norepinephrine.

Kava Kava (piper methysticum) is a tall shrub with large heart shaped leaves and roots that look like bundles of woody, hairy branches. The roots are ground up and used medicinally. The teas has long been a traditional ceremonial drink in the Pacific Islands. Kava contains kavalactones, specifically kavapyrones that reduce convulsions, promote sleep, and cause muscle relaxation. The tea produces relaxation and a feeling of well being. There have been cases of liver damage reported in humans.

Inositol is a carbohydrate (previously thought to be B-vitamin) that functions as a signaling molecule. It can modulate serotonin activity, thus producing a calming effect.

Red Raspberry Leaf (Rubus idaeus) is a source of magnesium and B vitamins. Studies both in vitro and in-vivo show that use of the leaves either as a tea or an extract, relaxes uterine muscles. The active compounds have not been definitely identified.

Chamomile (matricaria chamomilla) is an herb with a small white daisy like flower with a yellow center that is a member of the aster family (which also includes ragweed). The flower contains volatile oils that contain the active ingredients bisabolol, apigenin, luteolin, and matricin. Bisabolol has antispasmodic and anti-inflammatory properties. The constituents responsible for the sedative properties of chamomile have not been identified. The sedation is only mild.

Black Cohosh (actaea racemosa and cimicifuga racemosa) is a member of the buttercup family, a perennial plant that is native to North America. The roots are used medicinally. One active chemical is a saponin called 26-deoxyactein, but its mode of action is not known. Black Cohosh is most often used for female reproductive issues. A recently identified compound called fuinolic acid has some estrogenic activity. There have been a few isolated cases of liver failure in humans taking Black Cohosh.

Passion Fruit (passiflora incarnata) is a perennial creeping vine native to the Southern U.S. and South America. The whole of the above ground parts of the plant are dried and used to make tea. The plant contains alkaloids, glycosides, and flavonoids that in combination product the plants sedative effect. The plant also contain naturally occurring serotonin and maltol, which has sedative effects.

Ginger (zingiber officinale) is an herbaceous, perennial plant native to South Eastern Asia that is grown there, as well as extensively in Jamaica. The rhizome is used medicinally. Ginger contains oleoresins that are rich in gingerols. These compounds have a variety of sedative effects.

Calming Supplements are a training aid that can help your horse get through a sticky period, but they are not something to be depended upon.

Registered 2011 by Equestrian Collections
Author: Sallie S. Hyman, VMD, DACVIM, CVA

Information in this article is for educational purposes only and is not a substitute for evaluation by an equine professional. In particular, all horse owners should seek advice and treatment from a licensed veterinarian, such as TEVA, for their horses' medical care.

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