Published 9th January 2018

EquiFeast’s Chelated Calcium Journey of Discovery

This was a posting written in reply to a question on the Feeding Horses in Australia - Health. Nutrition and Property Improvements Facebook page in late March 2016

Enquiry from Julie Lannen:

Is it OK to ask Malcolm Green to explain the reasons why chelated calcium is the choice for horses that exhibit spooky behaviour (where training has not assisted) and why it is helping my gelding to become freer in his tight front end when others want to increase his mag dosage? and if I can be really bold why the issues that cause chelated cal to be used are not usually able to be measured scientifically (I know there are other successes as a result of cool calm and collected of course but I am being selfish)

Reply from Malcolm Green (EquiFeast Research and Technology Director)

Hi Julie,

I think I will answer the question by telling you the journey we had to get where we are today. It starts by the fact that our main business was always supplements for cage & aviary birds. We inherited a technology (from a vet) that was calcium gluconate (a chelate) presented in oral form (food or water) which we all just assumed was a really good, bioavailable form of elemental calcium. It was quite simply the stuff that vets had been injecting into animals for decades and we used it to treat and prevent all sorts of problems that we simply assumed were calcium deficiency.

These conditions were rickets, egg-binding, fits and seizures and other neuromuscular and skeletal conditions. I made an observation that there was a behavioural link too. Most obviously that birds that started to self-mutilate (many stressed parrots feather pluck) were never fixed unless calcium was addressed. Julie, you touched on training and there are all the same different views on animal training in pet parrots that exist in dogs and horses and often they failed with these admittedly quite extreme birds unless we gave them a calcium supplement. Of course, just like in horses calcium supplements have been given for decades (to be honest since the 1800s). The products of choice were cuttle bone and oyster shell grit (both calcium carbonate - exactly the same chemically as limestone).

The first adverts we placed in the UK bird market went out in October 1994 and promoted some hygiene products. With orders we sent a price list that also contained our vitamin and mineral supplements and (chelated) calcium. From December 1994 to today that calcium supplement has been our biggest selling product EVERY SINGLE MONTH! That is over 21 years.

Fast forward to 2004. My wife Sally was riding a bit and owned her own horse and I was ordered to do the same. As an almost non-rider (we had done a bit of riding when we lived in Australia and had enough acres for sheep, cattle and a couple of horses) I was foolish enough to buy a chestnut TH with four white socks. I am not completely mad - Paddy was a gelding not a mare.

I was an incompetent rider and Paddy was a typical skittish thoroughbred that would spook at the same pile of show jumps every time he went past them in the ring – for a whole hour. Bizarrely if they were stacked neatly they were less scary than if they were a jumbled pile. Hacking was exciting and he was tense, spooky and all the usual stuff. He was a weaver too.

At that point I naively thought that horse supplements manufacturers would have come across these issues before and have a solution. So I tried a whole pile of the usual (mostly magnesium) calmers to no avail. It never occurred to us that Paddy could be calcium deficient – after all there were lumps of limestone all over the pastures. Despite that we formulated our first products using limestone and magnesium oxide. I am now pretty sure the results we got were based purely on the antacid effect.

In 2008 I tried an experiment. One that would clearly not be economically viable as a liquid calcium gluconate product was far too expensive to produce for horse sized doses but was worth a try. We gave him a scaled up dose of the bird chelated calcium supplement. 25 minutes later he let out a big sigh and relaxed. Sadly it doesn’t always work that well. In fact such a response to a single application is probably very rare.

Later that year we ran some confidential trails that compared the effects of different calcium and magnesium sources on a about 10-15 “difficult horses” and the rough results were:

  • Chelated calcium had a positive effect on nine horses and a negative effect on one. We now understand why that negative probably occurred because we now know that timing of administration and riding can be important during the loading period.

  • Calcium carbonate had no effect on any horses at all – even though we gave much higher doses. This was the first clue that chelated calcium was very different to limestone – something we understand much better now.

  • Chelated magnesium and magnesium oxide both had a similar effect except that a lot more was needed from mag oxide than from the different chelates we used. This information is built into our Mag Factor calculations now. 

  • But the magnesium effects were dramatically different from the calcium ones. About 25% of riders reported an improvement in behaviour. About 35% reported a deterioration and the rest reported no change. There was no obvious difference between chelates and mag oxide.

This trial data was enough to get our patent on chelated calcium calmers that is approved in the UK, Australia and Canada and pending in Europe and the USA.

Chelated calcium calmers were born and rolled out during 2009.

Fast forward again to 2011 and by then curiosity was getting the better of me. I wanted to know how this technology worked. The scientific literature was non-existent. There is a simple explanation for this. All the billions of dollars of research that has been done on ion channels and calcium signalling relies of the electrical charge of the calcium, magnesium, sodium and potassium ions. But chelated calcium molecules carry no electric charge. To that science they are invisible.

So in late 2011 we started our first trials that included obtaining blood results from the clients vets. Two horses, Cry Freedon and Sir Roscoe, started us on the magnesium journey – but that is another story.

Science progresses by having a theory (hypothesis) and conducting an experiment. If the hypothesis is supported all well and good. If the results don’t fit the hypothesis has to be amended and retested. You will note that a lot of people, even those with science qualifications really struggle with this concept.

So our first mistake was to assume that chelated calcium was a source of calcium ions and that, according to the vet text books, only calcium ions were active in the blood and cells. So for our first blood trials the only calcium test we did was for ionised calcium (iCa). We were confident it would rise when the supplement was given. Imagine our surprise when iCa levels dropped in more horses than they rose!

Calcium in blood is normally considered in three groups:

• Protein bound – generally regarded as inactive.

• Ionised – definitely the stuff that operates calcium signalling and can be deposited in bones and teeth.

• Complexed – of which organic complexes or chelates are a component. Nobody ever mentions what they do and I doubt that anyone has thought about them before yet they form a natural component of the calcium in the blood and other body fluids.


Unfortunately there is no test for the complexed or chelated components. There is a formula (nearly 100 years old) that should enable us to calculate the amount of calcium in different protein fractions but that is a bit hit and miss. So the best we can ever do is see if there is a trend change in iCa and complexed. So from half way through our first trial we started to measure total calcium, protein, albumin etc. But in all honesty the results are really hard to interpret. But there was another big surprise.

If ionised calcium was the only important form of calcium then you would expect it to be very tightly regulated. But that appears not to be the case. Instead, the combination of complexed and ionised seems to be regulated by the very effective homeostatic system. But competition exists between the two groups. So horse grazing high limestone pastures have high iCa and therefore relatively low chelated calcium levels. This seems to explain why horses grazing these soil types benefit from chelated calcium supplementation.

Horses grazing low calcium pastures seem to have lower iCa levels but they can be replaced with high inorganic complexed calcium and still be deficient in chelated calcium.

In Australia the picture is further confused by high oxalate pastures. Calcium oxalate is a chelate but a bad one!

So we have some evidence that chelated calcium levels are somewhat vulnerable to other calcium sources but we still don’t know what they do or how they are managed.

Being inquisitive I signed myself up for an online Neuroscience course with Duke University. That and the text book that comes with it has proved very valuable. But so has just slogging through Google searches. What we now know is that chelated calcium molecules can be selected for and moved around the insides of cells through fancy channels called VDACs. These are closely associated with the parts of the cells where calcium ions are stored suggesting a possible link between chelated calcium and the removal of calcium ions from the cell cytoplasm to enable the cell to enter the resting mode. This is further reinforced by the anecdotal experience that horses that have a history of tying up don’t do so when on chelated calcium supplements and the same is true of short stepping oxalate poisoned horses.

This is the point at which to address your question about freeing up the front end of your horse. If the tension is caused by a failure to remove calcium ions from the muscles then it seems that chelated calcium somehow helps that process in a positive way. Magnesium may appear to achieve the same thing but in a negative way. EXCESS magnesium blocks calcium signalling. It does it two ways:


• In excess outside the cell it prevents the complete opening of channels called NMDA channels in nerve and muscle cells. That prevents the influx of calcium ions into the nerve and muscle cells so preventing them being activated properly – so muscle cells don’t contract

• In excess inside the cell it sits on calcium receptors and stops the calcium ions from switching them on.

So the appearance of relaxation is achieved by blocking natural processes rather than supporting correct function of the cells. Of course just as chelated calcium helps calcium signalling all over the body excess magnesium impairs it as widely. So the dangers of excess magnesium go far wider than increasing anxiety or impairing the decision making in front of jumps.

Which brings us to where we are now. Calcium signalling is used in the vast majority of the cells in the body. And chelated calcium seems to help with a whole host of issues. Our trials on oxalate poisoning suggest that is not a calcium deficiency disease but a calcium regulation problem. And chelated calcium fixes it probably by simply out competing the calcium oxalate for space in the blood.

That work led us to our Kissing Spine trial in the UK where chelated calcium seems to help these horses and show statistically significant impacts on muscle relaxation that creates a better foundation for traditional mobility support to build on.

An independent trial on performance horses by epidemiologist Jane Williams of the University of the West of England showed excitingly high significance for behaviour and performance characteristics in dressage, show jumping and eventing horses.

A Masters student at the Royal Agricultural University is working on chelated calcium and crib biters. To be honest I’m not confident we will kick that goal but she used a friend’s horse as a pre-trial guinea pig and the friend is determined to keep the horse on the supplement because of the overall behaviour gains. RAU are true experts on this because their senior lecturer is an expert on the striatum in the brain, how horses learn and the relationship between crib biters, dopamine release and the distribution of dopamine receptors.

For me the most exciting trial we are running (in conjunction with RAU) is on Cushing’s. Anecdotal evidence from a laminitis trial we ran last year is that chelated calcium is as good or better at eliminating symptoms and lowering ACTH levels in Cushing’s horses and ponies. We are struggling to recruit horses that are diagnosed or suspected but that are not yet being medicated so expect us to keep asking. We have horses in Canada and the UK and prospects in Australia for this trial but will be recruiting for a number of months yet. So if you know any prospects please put them in our direction.

You may of course ask how we think chelated calcium would help Cushing’s horses and the answer is that Cushing’s is a failure to make or release dopamine by the hypothalamus. That release is controlled by calcium signalling. Feedback from the first few trial horses to start is showing a reduction in eye blink rate – an apparently accurate proxy for dopamine release in the striatum. If it turns out to be a proxy for dopamine in the hypothalamus that would be a very useful diagnostic addition for vets in the future.

Julie you also asked why it is difficult to measure the effect of chelated calcium. In truth it would probably be quite easy to track these molecules around cells using something like radio-isotopes. And measuring it in the blood would probably be easy enough if the right biochemist worked on it. But developing the methodologies would probably cost millions of dollars. At the moment the drug companies don’t know about our work and even if they did they probably wouldn’t see a blockbuster at the end of it. So I am not optimistic that this will change much in the next twenty years. The glimmer of hope is the Cushing’s work. That may lead to interest from researchers in human Parkinson’s disease. But don’t hold your breath – recent developments involve incredibly expensive and invasive ways of delivering expensive drugs into the brain. A bonanza for Big Pharma and a select group of very skilled surgeons. Don’t expect an incredibly cheap 100ml bag of calcium gluconate to be able to compete with that for grant funding!

So Julie I have rambled on at length and I hope you have found it of some interest. But If I am really honest the answer to your question about why you should use chelated calcium is much simpler:

“It seems to help a lot of horses overcome a lot of problems.”