Whilst many riders seem to be searching for something to help take the edge off their horse, there also seem to be a large number of riders who are looking for a bit more “sparkle” or energy, especially when it comes to competitions. There could be many reasons why a horse lacks energy. The first is of course that the horse just has a very laid back temperament and just can’t see what all the fuss is about. Horses like this will of course be laid back at home as well as at competition and be like this all year around.  If a horse becomes more and more lethargic as the season wears on then we might have to consider boredom or if the season started in Spring, a chronic electrolyte deficiency. Many riders fail to feed sufficient electrolytes to horses in work and over several months deficiencies and imbalances can occur. Typically adding in an electrolyte supplement will start to show results (if this is part of the problem) within a few weeks.

Of course your horse could literally be suffering from a lack of energy if it’s in a negative energy balance. In simple terms this means that over a period of time your horse is using up more energy than its getting back from the diet. This could be due to simply not feeding sufficient energy. It could also be due to the fact that in theory you are providing the horse with enough energy but your horse is not actually getting that energy; for example due to intestinal parasites or to reduced digestive function. And if a horse is in negative energy balance then there will be a gradual loss of bodyweight over time. As always, it’s therefore important to ensure your horse is appropriately wormed. You may also have the impression that you are feeding your horse much more than others but it is very unwise to base what you feed on what others feed. In studies at Hartpury College sponsored by Spillers we found that for matched horses of similar age, breed and sex doing the same type of work, some horses would require TWICE the energy intake to maintain their body weight over a period of several months. Feeding should therefore be based on what your horse needs to maintain condition, not necessarily by exactly what it says on the bag or by what someone else says you should be feeding.

What and when you feed can also affect a horses’ energy levels, much in the same way as what we eat can affect our energy levels. Imagine having a large Italian meal for lunch with plenty of pasta and pizza. Lots of easily digested carbohydrates. The result? Within a few hours you start to feel lethargic. The same is true with horses. Give a feed high in starch a few hours before competing and by the time you enter the arena your horse may be ready for a post-prandial snooze. The reason for this is a rapid rise in blood sugar followed by insulin release and a rapid fall in blood sugar. Falling blood sugar makes us (and horses) feel less energetic. In some horses travelling long distances can make them less energetic. Remember that an hours’ travelling for a horse uses more energy than walking.

The last reason why your horse may be lethargic is due to illness. This could be a chronic illness (e.g. hypothyroidism, which incidentally is very rare) or to an acute viral or bacterial infection. If it’s the latter, it should only happen as a one off and the next competition your horse will likely be back to normal. If it’s truly a chronic illness then there will likely be other signs other than lethargy. In any case it’s important to discuss your concerns with your vet who can easily examine your horse and run appropriate tests which will hopefully reassure you that there is nothing medically wrong with your horse which may be contributing to lethargy.

So if your horse doesn’t seem to have as much energy as you would like, try to rule out any underlying illness by consulting your vet, make sure you allow time to recover following travelling (especially when over 3-4 hours), make sure you are feeding sufficient electrolytes and try to avoid feeding high starch feeds within 4h of competing.


If you are considering feeding an energy boosting supplement, then below is a review of the most commonly used ingredients in energy boosting supplements for horses.

Oats, barley, maize, etc

Grains that are high in starch (sugars chemically joined together) do provide quick energy once they have been digested in the small intestine. The only problems is that any undigested grains reaching the large intestine (hindgut) increase the risk of digestive disturbance and colic so avoid feeding large amounts and always feed with forage. In addition, the response to grains can be unpredictable. Some horses may react within a matter or minutes and some not at all. There is also the risk of a short term increase in energy followed by a crash when insulin kicks in and lowers the blood sugar.

Simple sugars – Dextrose (glucose), fructose (the form of sugar found in many plants)

These are included in many energy booster products. The problem is the same as with grains; a rapid increase in blood sugar which may increase alertness but release of insulin will bring the blood sugar back down and it’s impossible to predict how quickly the blood sugar will rise, how long it will stay up and when it will start to fall. The amount of sugar required to be fed is around 100-200g and few supplements on the market contain this amount.


Honey contains the sugars fructose and glucose and is sometimes used as an energy booster. The potential problems are the same as with pure sugars and starch-rich grains.

Complex carbohydrates

Although simple sugars and starches are not suitable as energy boosters, certain complex carbohydrates may be suitable if they can raise blood sugar without a significant increase in insulin. An example of a complex carbohydrate is EnerGex which produces half the insulin response compared with the same amount of glucose.


Possibly the most commonly used ingredient in equine energy boosters. The theory for iron seems to be related to the fact that people who are anaemic have low energy levels. Anaemic people have low numbers of red blood cells. Iron is key component of haemoglobin – the oxygen carrying protein that is contained within red blood cells. Iron is also involved in the immune system. Iron deficiency in horses in the UK is rare. Anaemia in horses due to iron deficiency is very very rare. The horse has limited capacity to excrete excess iron taken in from the diet and excess iron can lead to increased susceptibility to free radical damage, infection and abnormalities in iron regulation. “There is little rationale for additional iron supplementation providing horses are fed diets with at least 50ppm iron [most diets will exceed this level]. There is no evidence of an increased erythropoiesis [red blood generation] with iron supplementation. Coenen in Equine Applied and Clinical Nutrition, Saunders, 2013. When looking at the label of a supplement containing iron it may not be listed as “iron” but as “ferric” or “ferrous”.


Magnesium is normally used as a calming supplement. However some energy supplements also contain magnesium which appears contradictory. There is evidence from one study that very high doses of magnesium reduce reaction time in horses. Therefore it is questionable whether magnesium would be an effective energy booster.

Amino acids

Proteins are made up of amino acids. The proteins are digested in the stomach and small intestine and the individual amino acids taken up into the blood stream. Different amino acids have different functions. Leucine, isoleucine and valine (together termed BCAA or branched chain amino acids) have been shown to alter endurance exercise capacity in human subjects in some studies. Whilst BCAA at the appropriate dose rate may have a role in endurance exercise, there is no evidence to suggest they will increase energy levels in horses taking part in short-medium duration displines such as jumping, dressage, polo, racing or eventing.


L-carntine is involved in the fat metabolism. The rationale for supplementation is that it may increase fat use as an energy source and in turn save or “spare” muscle glycogen. None of the studies conducted in humans or horses to date suggest that carnitine supplementation has any effect on a horses energy levels.

Co-enzyme Q10

Co-enzyme Q10 (also known as ubiquinone or sometimes just as Q10) is found mainly in the mitochondria of cells and is part of the process that regenerates ATP in the electron transport chain during aerobic metabolism (the process of transferring energy contained in carbohydrates and fats to ATP using oxygen).  This is the rationale for it being sold as an energy booster. In our diet we obtain Q10 from meat and seafood. The US National library of Medicine rates Q10 as “likely ineffective [for] Athletic performance. Taking coenzyme Q-10 by mouth does not improve athletic performance in athletes or non-athletes.” To date there are no studies on the safety or efficacy (effectiveness) of Co-enzyme Q10 as an energy boosting supplement.


High quality scientific studies show no effect of feeding high doses of creatine to horses for up to 90 days. In addition, other studies show that horses absorb only a very very small percentage of any creatine fed in the diet. Not only will you be wasting your money, studies in humans have shown an increased risk of kidney damage.


There is only one study of ginseng in horses. Whilst no adverse effects were observed, ginseng did decrease plasma sodium and increase plasma potassium. As the horses were not in training the effect on ability to train or performance cannot be determined. There is also evidence from other species that ginseng may lower blood sugar and increase blood clotting time. Lowering of blood sugar would tend to reduce energy levels rather than increase them.

Ginkgo biloba

Ginkgo biloba extract is used in many human supplements and suggested to benefit memory and cognitive function, depression, various psychological conditions, tinnitus, reduce limb pain caused by blocked arteries and relieve PMS symptoms. There are few references to improved energy levels. A recent scientific review of evidence for specific claims relating to improvement of blood circulation, improvement of symptoms of old age, and improvement of memory reviewed 35 human studies and concluded that the claims could not be substantiated [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950792/]. There do not appear to be any studies on the efficacy or safety of feeding Ginkgo biloba to horses:

B Vitamins

In people anaemia, fatigue and weakness can be symptoms of low B Vitamin intake and this forms the basis for the inclusion of B Vitamins in energy boosting supplements. Limited scientific information exists on B Vitamin requirements of horses or on toxic levels. B Vitamin “tonics”, often in the form of an injection, have long been a popular treatment from vets. However, there is currently no evidence to support the use of B Vitamin supplements as energy boosters in horses.

A word of warning!

There are a number of ingredients which are known to have energy boosting effects but which are classified as banned substances. Examples of such substances include caffeine, capsaicin (from peppers), synephrine (particularly high in Bitter Orange but also found in leaves, rind and juice of other citrus fruits) and amphetamines. Whilst you may not intentionally set out to feed any of these substances, it is essential if you are competing to be reassured that the products you are using are from companies who source their raw materials from approved suppliers and carry out their own independent testing to ensure that ingredients are not contaminated or adulterated with prohibited substances. Membership of the BETA NOPS scheme would be a bare minimum in this regard. The BETA NOPS scheme helps to reduce the risk of potential “natural” contaminants that may get into horse feed and supplements. For example contamination with morphine from poppies. The BETA NOPS scheme does NOT however guarantee that a product is free of all prohibited substances. This will depend on what individual manufacturers undertake in terms of testing of raw materials and finished product and where they source their ingredients from. You can find out more about the BETA NOPS scheme here: http://www.beta-uk.org/pages/feed-safety/beta-nops-scheme.php    


For the majority of ingredients commonly used in equine energy boosters, there is no evidence to suggest they will increase energy levels and in fact in many cases they may have the opposite effect or have other undesirable side-effects. The two most commonly included ingredients in energy boosting supplements are iron and B Vitamins. These are inexpensive ingredients and the rationale for their use is distorted and based on poor scientific understanding. In addition, there are NO controlled studies which provide any evidence that iron and B Vitamins will increase energy levels in horses which are not severely deficient. Deficiency in iron and B Vitamins is extremely rare in horses in the UK. For some ingredients, whilst they may have some efficacy, the levels included in the supplements may be below that required or shown to have an effect. Finally, its essential to be confident that any supplement you do use does not intentionally or accidentally contain prohibited substances.

Author: Dr David Marlin


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