calming supplements & the placebo effect

I had a really tough ride on Suzy this week, which led me into a discussion with my barn manager about possibly giving her another dose of depo.  Barn manager suggested that since I spend a lot of time with Suzy, I’d be able to help Suzy’s owner decide if her behavior warranted another dose.  Now, there’s not a lot (almost none, but perhaps there is something I haven’t dug up yet) of evidence that depo actually does anything in horses, despite many, many, many anecdotes to the contrary.  Absence of evidence isn’t evidence of absence, but I’m not really one to go adding hormones to someone’s lifestyle without a pretty good reason.

seemed appropriate here

This led me to think about the hundreds of calming supplements and treatments available for horses that have little to no evidence of a significant (or even potentially biologically relevant) effect upon behavior.  Hell, I use one of them!  Yet so many of us cling to these supplements and swear up and down that they are doing something.

But the placebo effect is a strong and very legitimate thing. Whether or not the placebo effect is causing actual physiological changes or is being exploited by companies to sell sham products, it is a very easy trap to fall into. Most of us are going to add calming supplements to a horse’s diet after they’ve been particularly wild and crazy for some amount of time — maybe a week’s worth of rides.  But if those particularly wild and crazy days are outliers, or even just somewhere on the edge of “normal” for that horse, then his behavior is going to trend back toward normal whether you add the calming supplement or not.  Those days were abnormal, and unless there’s something else significant going on to change the horse’s behavior (totally plausible — but not necessarily the case), the added calming supplement most likely did nothing.  The horse’s behavior was going to go back toward “normal” anyway.

big spikes of bad behavior like this == abnormal

Let’s say that we rate Murray’s badness on a very scientific scale of 1-10 each day: 1 is totally normal, no bad behaviors performed, 10 is rearing and striking.  (For the record, I’ve never experienced either a 1 or a 10 day.)  If Murray tends to hover around a 3.5 because he likes to get down with his bad self, but suddenly spikes up to an 8 one day, I’m likely to dump a bunch of extra magnesium in his bucket for a few days.  And then, because being a level-8 bad boy is a really unlikely occurrence, we just slide back toward the average. Which is both statistically and realistically much more likely to occur on any given day.

Especially because the way we think of behavior (or anything with a gradient, basically) tends to fall on a bell curve.  If we assume that each behavioral category is roughly on standard deviation away from the next, it means that behaviors in the “average” category occur 68% of the time. Behaviors one more standard deviation away from average occur with 95% frequency.  If being slightly nutty or slightly better than average is occurring with 95% frequency, any time you have a bad day, you have something approaching a 95% chance that your next ride will be better (assuming the two days are independent, which they aren’t).

So when we’re adding calming supplements, or more invasive approaches to calming behavior, how are we to know if we are really doing anything?  There are ways to test it — you could blindly rank your horse’s behavior every single day that you spend with him while another person either gives him that supplement or a sham supplement. Then you’d compare the distributions of behaviors demonstrated.  I just turn to the science.  Of course, there’s really not a whole lot of peer reviewed research in this area, which is frustrating.

All of this is not to say that I don’t believe in calming supplements or that diet can change behavior.  Obviously I do, and there are some behaviors that I have seen decrease rapidly with the right change in diet.  I am completely certain that if we mapped Murray’s behavior when he’s on alfalfa and compared it to his behavior off alfalfa, we’d see a significant difference.

even walking is hard when Murray eats alfalfa

But it does mean that I approach adding supplements like this with a fair bit of caution, and I pretty much don’t believe what I read from testimonials on the internet.  People are notoriously bad at understanding probability and statistics without training in those areas, and we love just-so stories.  We also really, really want to help our horses, and they can’t talk to us and say “I’m feeling a little extra girthy today, how about you take it extra slow while we tack up?” (I mean, sure, he does say that to me. It’s just usually while I’m tacking up and it’s a leeetle bit too late.)  It also means that I don’t pay too much attention to any one ride, or even any one week, when making decisions about this stuff.  One day is an outlier.  A whole week… could easily be a rough week.  Especially when there’s other stuff going on in the world that might influence behavior more than supplements do — changes in turnout, routine, weather… I’m seriously convinced that when the barometer drops, Murray’s brain swells and hurts his little head, because he’s usually much worse before a storm than during!

I may also use this logic to aggressively convince myself out of using supplements that might help. When barn manager originally told me to take Murray off alfalfa I was like “NAW THAT’S NOT A THING”.  Same with adding magnesium.  And both of those things had a huge positive effect on Murray’s general outlook on life.

So, how do you approach adding and subtracting supplements like this?  Just go with the prevailing wisdom? Trust your gut? Appeal to nature?

22 thoughts on “calming supplements & the placebo effect”

  1. I think you bring up some really great points! Overall, I don’t think there’s a really solid way of measuring the effectiveness. For one, I think each horse could react differently and to say it does/doesn’t work for one doesn’t mean you can apply that to all or even the majority.
    I actually put Estella on Quietex last week to see if it could help her take the edge off for the transition between Bella and Arya. It’s my first time using something like this. To be honest, she has been way better about it than I expected. But I will NEVER know if that was because of the supplement or not, because I will never be able to replicate it without the supplement lol. I think it probably helped, but I also don’t have any intention on keeping her on it once we use it all. Maybe if shit hits the fan when it’s done then I will know if it was helping or not lol.


  2. I like your math/science based reasoning on this topic! Truly you’d have to test various supplements or drugs in a very controlled environment to get any sort of real set of data to use (but I think the study would be worthwhile and valuable). I can say that the one thing that has always helped and not hurt my horses has been Magnesium:) Scout gets Daily Gold now, which does have magnesium but also lots of things for his belly. Also, horses, much like humans have good days and bad days, and I think we have to cut them a little slack for getting up on the wrong side of bed or having an ache or pain or tension that we cannot see, that is, as long as it only lasts for a day or two:)


  3. I’ve used calming supplements in the past (Carlos) with good success. Ramone I gave a paste calmer to for trailering only and Dante has had nothing yet – just turnout and lunging seem to do the trick for him right now.

    Liked by 1 person

  4. i’m not sure there’s a one-size-fits-all approach, and there are so many different factors that go into how a horse responds (or doesn’t) to a supplement that it can be really difficult to truly know what’s driving the behavior.

    honestly, i think it’s sometimes true in a lot of what we do with horses that we end up spending some extra $$ to make our selves feel better too. which then begs the question: if we give our horses a calming supplement, and we, by placebo effect, believe the horse to then be calmer and simply just expect the horse to be better… then if the horse is a reflection of our own moods and expectations (which they arguably often are) and thus actually does become calmer or better bc we are treating it as if it were…. does that still count as a win for the supplement? even if the only true change was our own mental attitude or approach to the horse?


  5. As every horse person knows, the plural of “anecdote” is “data”.

    I kid, I kid. I’ve actually been thinking about this quite a bit, because I recently downloaded an app to track the symptoms of my chronic illness and it’s pretty neat. In addition to tracking my symptoms, I can put in my meds and supplements, what I’ve eaten and how much water I drank. It also tracks my activity level through the phone’s step counter and could be synced with a Fitbit type thingy if I had one. Then it gives me charts of my symptoms, food choices, supplements, meds and activity so I can track how I felt vs what I did, ate and took.

    It would be really cool if we could get a riding app to do the same thing. All the ones I’ve seen just track how long you rode, but imagine if we could also log “symptoms” (girthy, sluggish, total asshole) and supplements and feed and then compare them! I think one of the toughest things with figuring out lifestyle changes is that we don’t really accurately remember things over time. If we record them in real time, we get a better picture of whether or not something is helping.

    As far as placebo effect goes, another thing I’ve noticed is that if a trusted trainer recommends something, the horse almost always gets better. I think sometimes it’s a confidence issue: the trainer says, “This will make Poopsy go better”, the rider subconsciously rides with a little more confidence because they believe Poopsy is going to go better, and Poopsy does go better.


    1. Yes! Emma brought this up too, the placebo on the rider! I didn’t think about it when writing this post, but I’ve thought about it a lot on my own.

      That app would be cool, and I can see all kinds of side benefits to it when you get enough data going. Will just add it to my never ending list of ideas of things that would make the world better.

      Liked by 1 person

  6. I have tried various calming supplements on Carmen and have not noticed any real difference. I am cautious of supplements for that reason and tend to look for evidence first.


  7. Love the science based posts.

    I was leery of pre-made supplement mixtures, but wanted to promote calmness. I did a good bit of research, and was lucky to have access to some data shared by a vet. The conclusions from a 10,000 sample study suggested that hay in general, supplies at best less than 50% of the rda of magnesium for horses. Val is on a dry lot – if your horse has pasture it’s a whole different ball game. Then I got out the feed bags and did some math. I weigh out Val’s feed so the numbers were fairly accurate. Turned out he was significantly lacking magnesium. The plural of anecdote isn’t data, but my results have been great, and I have no desire to test my theory by removing the magnesium either.

    Liked by 1 person

    1. I’ve read that most hay based diets are magnesium deficient too! Good to know that multiple sources corroborate this. Can’t blame my horse for being a whackadoo if he’s deficient in an essential mineral!


      1. When I switched to grain free diets I noticed several of my horses got tense and reactive. I added a magnesium supplement and they went back to normal. They’re still not “calm”, but definitely not as muscle sore. I use one that’s labeled for metabolic, not calming, though.


  8. I figured the calming effect of Mare Magic was more on me, than my mare, but was willing to try it during those pesky, don’t wanna die winter night lessons.


  9. I’m with Emma and others re: rider behavior changing due to expecting supplements to work and thus horses behavior changes with rider. I have tried a few calming supplements with no marked difference. Now I tend to dig more into my own behavior to see if it caused a change in my horse before resorting to supplements. Way cheaper and I’ve had markedly better results!


  10. Very interesting topic. I asked my vet (not my regular vet, but the one who treated Knight in the hospital when he colicked and had extreme ulcers) about the alfalfa making horses hot. He said there’s no evidence, but I thought, “What about all the horse owners with anecdotal evidence?” He said if alfalfa made Knight high, he’d consistently be high, not every now and then. I’d be interested in a study based on horses’ lifestyle. Do horses living in 24/7 turnout need calming supplements like their stalled counterparts? I’m interested in learning more about magnesium.


    1. I would love to know more about these questions also! My understanding from nutrition reading is that horses who have full time turnout with enough browse and forage that they can nibble on to balance their diet should not need magnesium. However, there are horses I know who live in California turnouts (4 acre pastures but mostly grasses and a few weeds, not diverse forage) who do benefit from magnesium. Ugh so many questions!!

      And just to throw my own anecdote in there, when Murray is on alfalfa, he is “high” all the time. I do think that certain horses have a sensitivity to afalfa, but yet another thing worth studying and identifying!

      Liked by 1 person

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