Glucosamine for horses: effects, dosage & why feeding is the real challenge

You've heard of glucosamine, but aren't exactly sure what it actually does, how much your horse needs, or how to get your horse to eat it in the first place? Then you're in the right place.

We are Katja and Andrés from nuvallo. With over 20 years of practical experience in horse keeping, we know first-hand what horses will actually eat – and what they'll leave behind. That's why we're explaining in this article, in easy-to-understand terms, what research says about glucosamine and how you can feed it optimally.

What exactly is glucosamine?

Glucosamine is an amino sugar that your horse's body produces naturally. It is one of the most important building blocks for articular cartilage and synovial fluid (joint fluid). Think of glucosamine as a raw material: your horse needs it to maintain the 'shock absorbers' in its joints.

Specifically, the body uses glucosamine to produce so-called glycosaminoglycans (GAGs). These are the molecules that give cartilage its elasticity and ensure that the synovial fluid remains nicely viscous and lubricating. Hyaluronic acid – you might know the term from skincare – is also built from glucosamine.

As long as your horse is young and healthy, it produces enough glucosamine on its own. However, with increasing age, under heavy workloads, or when joint problems such as osteoarthritis are already present, the body's own production can no longer meet the demand. This is exactly where the idea of glucosamine supplementation comes in.

Glucosamine effects in horses: What does the science say?

Now it gets interesting – and we'll be honest with you: the current state of research is promising, but not quite as clear-cut as many manufacturers make it out to be.

What has been proven in the laboratory:

Researchers at Michigan State University have shown that glucosamine inhibits cartilage-degrading enzymes in laboratory tests, reduces inflammatory markers such as nitric oxide and prostaglandin E2, and blocks an important inflammatory signalling pathway (NF-κB). That sounds fantastic – and it is. But: these results come from Petri dishes, where the cartilage is directly bathed in a highly concentrated glucosamine solution. In a living horse, the situation looks different.

What has been studied in live horses:

The most convincing study to date comes from Texas A&M University (Leatherwood et al., 2016). In 14 young horses that received glucosamine over 84 days, the inflammation markers in the synovial fluid measurably decreased, while at the same time the markers for new cartilage formation increased. These are encouraging results.

An older study by Auburn University on 25 horses with joint problems showed a significant improvement in lameness after just two weeks – however, it lacked a control group, which limits the reliability of the findings.

Other studies, however, found no measurable difference between glucosamine and a placebo. A systematic review from 2009 found that only 3 out of 15 published equine studies actually met minimum scientific standards.

Why the results vary so much:

The main reason is so-called bioavailability. When your horse ingests glucosamine orally, only about 6–10% of it actually reaches the bloodstream. The University of Montréal proved this in a pharmacokinetic study. Of what reaches the blood, only a fraction makes it into the synovial fluid.

But there is an interesting glimmer of hope: the same research group discovered that inflamed joints absorb about four times the amount of glucosamine compared to healthy joints. The active ingredient therefore preferentially accumulates exactly where it is needed most. This possibly explains why many horse owners observe positive changes despite the modest bioavailability.

Our conclusion on its effectiveness: The biological foundation is solid. Glucosamine is not a miracle cure, but it is a sensible building block – provided the dosage is right.

Glucosamine dosage for horses: How much does your horse really need?

And herein lies the problem with many products on the market. The dosages used in the scientific studies that showed positive results are significantly higher than what most commercial products recommend.

The pharmacokinetic studies at the University of Montréal worked with a standard dose of 20 mg per kilogram of body weight per day. For a 500 kg warmblood, that equates to 10 grams of glucosamine daily. The Texas A&M study, which showed positive results in inflammation markers, even used double that amount.

As a guide for pure glucosamine as a single active ingredient:

For the daily support of healthy joints, you should calculate 10–20 mg per kilogram of body weight. For a 600 kg horse, that's 6–12 grams per day. During acute phases or as an initial loading dose, it can be 15–20 grams daily, before reducing to a maintenance dose after 2–4 weeks.

But – and this is crucial: These high dosages refer to studies where glucosamine was fed alone. When glucosamine is specifically combined with other active joint ingredients – such as MSM, collagen, and hyaluronic acid – the ingredients target different areas within the joint and mutually reinforce one another. This synergistic effect means that you don't need the same amount of glucosamine as you would with a single supplement to achieve a comparable result. The combination works as a team, not as a collection of individual players. More on this below.

And now for the sobering reality of the market: A study in the Equine Veterinary Journal tested 23 commercially available glucosamine products for horses. Over half of them contained less glucosamine than stated on the label. Three products had less than 30% of their declared content – and one product contained no glucosamine at all. Out of the 23 products, only 5 recommended a daily dose that came close to the 10 grams investigated in scientific studies.

Important: Glucosamine takes time. Don't expect results after one or two weeks. Most experts recommend at least 8–12 weeks of consistent feeding before judging whether the supplement makes a difference. For cartilage repair, it can even take 3–6 months.

Glucosamine hydrochloride or glucosamine sulphate?

In case you're wondering which form is better: The University of Montréal compared the two directly. Glucosamine sulphate achieved a bioavailability of 9.4%, while glucosamine HCl stood at 6.1%. The concentrations in the synovial fluid were also significantly higher with the sulphate.

The minor catch: Glucosamine HCl consists of about 80% pure glucosamine, whereas glucosamine sulphate (especially the common 2KCl-stabilised variant) only contains 50–60%. So, you need more powder of the sulphate form to deliver the same amount of active ingredient. In return, however, more of it actually reaches the joint.

An additional advantage of the sulphate form: It provides sulphur, which the body also requires for cartilage formation. If you opt for the HCl form, it therefore makes sense to feed MSM additionally as a source of sulphur.

Why glucosamine alone is often not enough: The power of combination

In practice, glucosamine is rarely fed in isolation – and for good reasons. Different active ingredients target different areas within the joint and reinforce each other. That is why a well-balanced combination product does not require extreme individual dosages.

MSM (Methylsulfonylmethane), 7.5% in nuvallo move, provides organic sulphur, which is indispensable for cartilage formation, and simultaneously has anti-inflammatory and antioxidant effects. In a study on 30 racehorses given 20 grams of MSM per day, recovery improved, inflammation markers dropped, and the trainers even reported better coats and hooves. MSM complements glucosamine perfectly because it provides the sulphur the body needs for cartilage formation from glucosamine – essentially the second key to the same lock.

Collagen, 8.5% in nuvallo move, provides the body with the amino acids glycine and proline, which it needs to build connective tissue. While glucosamine primarily supports the 'filling' of the cartilage (the glycosaminoglycans), collagen strengthens the framework that holds this filling together. A particularly interesting form is undenatured type II collagen (UC-II): even small amounts can modulate the immune system and thus reduce the body's own attack on joint cartilage. One study even found UC-II to be more effective than the combination of glucosamine and chondroitin in arthritic horses.

Glucosamine – 5% in nuvallo move provides the central building block for glycosaminoglycan synthesis. In combination with MSM (which provides the necessary sulphur) and collagen (which strengthens the cartilage framework), glucosamine can exert its effect even in more moderate amounts than when fed in isolation.

Hyaluronic acid – 0.5% in nuvallo move is something you might know from joint injections at the vet. Whether orally administered hyaluronic acid actually reaches the joint intact is still under scientific debate. However, a study on Thoroughbreds showed that oral administration reduced joint swelling after surgery. An in vitro study by Ohio State University found that hyaluronic acid combined with glucosamine lowered inflammation markers more effectively than hyaluronic acid alone.

Why the combination is more than the sum of its parts: The strongest evidence for this comes from a randomised, blinded crossover study by the Animal Health Trust, where a supplement containing glucosamine, chondroitin, MSM, and omega-3 fatty acids reduced the degree of lameness and improved mobility. Fed individually, none of these active ingredients would have had the same effect at the dosage used. This exact principle – four active ingredients that specifically complement each other – is behind the recipe of nuvallo move.

Feeding glucosamine to horses: The biggest problem isn't the active ingredient

And now we come to the topic that is closest to our hearts at nuvallo – because we have experienced it hundreds of times ourselves.

You can buy the best, most highly dosed glucosamine product in the world. You can calculate the perfect dosage. You can create the optimal feeding plan. But all of that is absolutely useless if your horse won't eat the stuff.

And that is not uncommon. As an amino sugar, glucosamine itself tastes slightly sweet and is often well accepted. But joint supplements don't just contain glucosamine. MSM has a slightly bitter, sulphurous taste. Collagen smells unfamiliar to sensitive equine noses. And green-lipped mussel extract – another popular joint ingredient – brings an intense fishy smell that immediately sets alarm bells ringing for many horses.

On top of that: Most joint supplements are powders. And powders come with several problems at once. They are dusty, which irritates sensitive nostrils. They change the consistency of the usual feed. And horses are frighteningly good at sorting them out – especially when they simply push aside damp feed serving as a 'lid' to eat the dry hard feed underneath.

Even if your horse initially accepts the powder, that does not mean it is ingesting the full dose. Residues left at the bottom of the manger, clouds of dust blown out while eating, sorting out – in practice, your horse often gets significantly less than the calculated amount. And with an active ingredient that only has a bioavailability of 6–10% anyway, every gram counts.

We know the usual tricks: introduce it slowly over 7–14 days, dampen with water, mix into soaked sugar beet pulp, add a spoonful of apple sauce. That works for some horses. For others, you stand frustrated at the manger every evening, wondering if the €50 for the supplement has simply vanished into the bucket – quite literally.

Sources

Byron C.R. et al. — Effects of glucosamine and chondroitin sulfate on mediators of osteoarthritis in cultured equine chondrocytes (American Journal of Veterinary Research, Michigan State University, 2003) Link

Leatherwood J.L., Gehl K.L., Coverdale J.A., Arnold C.E., Dabareiner R.A., Walter K.N., Lamprecht E.D. — Influence of oral glucosamine supplementation in young horses challenged with intra-articular lipopolysaccharide (Journal of Animal Science, Texas A&M, 2016) Link

Meulyzer M., Vachon P., Beaudry F., Vinardell T., Richard H., Beauchamp G., Laverty S. — Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulphate or glucosamine hydrochloride (Osteoarthritis and Cartilage, Université de Montréal, 2008) Link

Meulyzer M. et al. — Joint inflammation increases glucosamine levels attained in synovial fluid following oral administration of glucosamine hydrochloride (Osteoarthritis and Cartilage, Université de Montréal, 2009) Link

Laverty S., Sandy J.D., Celeste C., Vachon P., Marier J.-F., Plaas A.H.K. — Synovial fluid levels and serum pharmacokinetics in a large animal model following treatment with oral glucosamine at clinically relevant doses (Arthritis & Rheumatism, Université de Montréal, 2005) Link

Gupta R.C. et al. — Therapeutic efficacy of undenatured type-II collagen (UC-II) in comparison to glucosamine and chondroitin in arthritic horses (Journal of Veterinary Pharmacology and Therapeutics, 2009) Link

Kilborne A.H. et al. — Effects of hyaluronan alone or in combination with chondroitin sulfate and N-acetyl-D-glucosamine on lipopolysaccharide challenge-exposed equine fibroblast-like synovial cells (American Journal of Veterinary Research, Ohio State University, 2017) Link

Bergin B.J. et al. — Oral hyaluronan gel reduces post operative tarsocrural effusion in the yearling Thoroughbred (Equine Veterinary Journal, 2006) Link

Murray R.C. et al. — Effect of an Oral Joint Supplement on Orthopaedic Evaluation Scores and Limb Kinematics (Equine Veterinary Journal, 2014, Animal Health Trust crossover study) Link

Marañón G. et al. — The effect of methyl sulphonyl methane supplementation on biomarkers of oxidative stress in sport horses following jumping exercise (Acta Veterinaria Scandinavica, 2008) Link