Choosing the Right Calming Supplement for a Nervous Horse

Updated July 25, 2024 | By: Dr. Lydia Gray

"I have a spooky Arabian/National Showhorse mare. She is very sweet and quiet on the ground, but under saddle she is inclined to be nervous. She has only bolted once, but she spooks often. I’m 58 years old and just want to walk and trot her on trail rides. Is there a safe daily supplement that I can give her to help calm her? She is 21 years old and in very good condition."

- EC, Florida


"I have a 7 year old ex race horse who is very nervous. I have him on a vitamin B1 supplement and I was wondering if I should put him on a magnesium supplement or would that be too much?"

- KA, Texas


"I have a horse that was once a stallion and is still very dominant and pushy. I had him on Quiessence and that worked okay but not as well as I would have liked. My horse is pretty spooky and is very nervous outside where if he gets scared, he bolts and then stays very tense. I was just wondering if Quiessence is the best supplement to have him on or should I try something else? I still need him to have energy to perform upper-level dressage but is there anything I can put him on to take the edge off?"

- NT, Colorado


very alert horse with ears up

Dear EC, KA and NT,

Before I recommend a calming supplement to any of you, my first piece of advice is: review your horse’s management and see if there is anything you can do to improve the situation. For example, is your horse on appropriate nutrition? (plenty of forage, grain replaced by a vitamin and mineral supplement or ration balancer, salt and water). Next, does your horse have plenty of turnout that includes interaction with other horses? (24/7 is ideal, 8-12 hours is good, 4-6 hours is okay, less than that might be a problem).

If you have these basics covered, then it may be time to try a calming supplement. As you probably know from looking through the products, there are herbal ingredients and non-herbal ingredients. The herbal ingredients are things like chamomile, hops, valerian and vervain, all considered “nervines” because they are herbs with specific actions on the nervous system. What is particularly interesting about these four herbs is that they are each believed to work best on a certain type of nervous horse.

  • Chamomile: for horses that process anxiety through their GI system (colic, diarrhea)
  • Hops: for horses that process anxiety through their head (unfocused, distracted)
  • Valerian: for horses that process anxiety through their muscles (tight, also teeth-grind)
  • Vervain: for horses that process anxiety through their skin (twitchy, jumpy, fidgety)

You may also see the herb passionflower in some herbal calming products. It is believed to complement the nervines by facilitating their effect. The principle of using herbs to calm a horse has to do with rebalancing, re-educating or resetting the nervous system.

Passionflower is said to be especially helpful in breaking old nervous system patterns and allowing new ones to be set. Therefore, horses that respond to one or more calming herbs may not necessarily need to be on them for life, although some may. Most horses can be taken off the calming herb after improvement is seen and need only go back on it during particularly stressful events such as a change in barns or owners.

Non-herbal ingredients are a different story. In general, non-herbal calming ingredients (such as Vitamin B-1, Magnesium and Taurine, an amino acid) are believed to work in some nervous horses because they have a dietary deficiency in those nutrients.

Other ingredients may augment the amount of one of the body’s natural calming compounds, serotonin, a neurotransmitter whose brain levels are known to be a factor in anxiety. Inositol (a B-vitamin), participates in the action of serotonin, while tryptophan (an amino acid), is actually converted into serotonin, whose action in the body is to calm, soothe and produce feelings of contentment.

One final word of advice: if you are competing with your horse, make sure you know your association’s rules for what ingredients you can and cannot give your horse. Otherwise, review the way your horse is currently managed then try one or more of the ingredients above to see if your horse responds. Be sure and give each product at least four weeks to produce an effect, and if one product or ingredient doesn’t work, try another! Every horse is an individual and will respond differently to supplements for calming.


SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.