MSM for Your Horse: Effects, Dosage & How Long to Feed It

We are Katja and Andrés from nuvallo. Having stood at the feed trough with our own horses for over 20 years, we know the uncertainties surrounding joint feeding from first-hand experience. In this article, we explain clearly what MSM is, what dosage makes sense, how long you should feed it, and what the research actually says.

What exactly is MSM?

MSM stands for methylsulfonylmethane, an organic sulphur compound naturally found in plants, soils, and the horse's body itself.

Sulphur might sound rather unspectacular at first. In fact, after calcium and phosphorus, it is the third most abundant mineral in your horse's body, and it has a more important job than most people realise. Sulphur is found in the amino acids methionine and cysteine, and without these, the body cannot produce collagen or keratin. This means: no stable cartilage, no elastic tendons and ligaments, no resilient hoof horn, and no glossy coat.

Think of sulphur as the mortar that holds the bricks of a house together. The bricks themselves – collagen, glucosamine, and keratin – are important. But without the mortar, nothing holds together.

Why might a supplement be useful? Because the sulphur content in basic forage fluctuates significantly depending on the soil, fertilisation, and harvest time. On top of this, older horses, sports horses under heavy workloads, and horses with early joint issues have an increased requirement. MSM provides this sulphur in a form that the body can easily utilise.

The effects of MSM on horses: What does the science say?

The most important point first: the research on MSM is promising, but not as definitive as many manufacturers make it out to be. We will therefore take a close look at what has been proven in the laboratory, what has been studied in living horses, and what this means in practice.

What has been proven in the laboratory

In cellular studies, MSM shows two main effects that are relevant to joints. Firstly, its anti-inflammatory properties: research teams at Seoul National University (Kim et al., 2009) and Kangwon National University (Ahn et al., 2015) independently demonstrated that MSM inhibits the NF-κB signalling pathway, a key switch for inflammatory responses. Specifically, MSM reduces the production of inflammatory messengers such as IL-6 and TNF-α. At the Ludwig Boltzmann Institute for Rheumatology in Vienna (Kloesch et al., 2011), this effect was even confirmed directly on human cartilage cells. Secondly, antioxidant protection: MSM supports the formation of glutathione, the body's most important antioxidant, and can thereby reduce the oxidative stress that occurs more frequently during intensive exercise and old age.

Important for context: laboratory results cannot automatically be applied to the living horse. The concentrations used in cellular studies are often significantly higher than what actually reaches the bloodstream through feeding. However, they provide a solid biological foundation for why MSM can be effective.

What has been studied in the living horse

The best-known study comes from Marañón and colleagues (2008, Acta Veterinaria Scandinavica). They examined 24 showjumpers during a competition in Spain. The horses were given MSM for about six weeks and subsequently showed significantly less oxidative stress following exercise, meaning lower levels of lipid peroxidation and nitric oxide, alongside higher glutathione levels. The effect was most pronounced in the group that received MSM together with vitamin C.

Another investigation involving 30 Standardbred racehorses (Riegel, 2001) compared 10 g and 20 g of MSM per day over eight weeks with a control group. It found lower markers of muscle damage, improved training times and, according to the trainers, better coats and stronger hooves. To be entirely honest, it must be noted: this study was only published as a conference paper and was not peer-reviewed, so its results should be treated with caution.

A recent study by Barshick et al. (2025, Animals) examined 10 Thoroughbreds receiving 21 g of MSM per day for 30 days. Muscle biopsies showed improved anti-inflammatory gene expression following exercise, an interesting piece of evidence that MSM also reaches the horse's body on a molecular level. Furthermore, a large meta-analysis by Liu et al. (2018, British Journal of Sports Medicine) evaluated 69 studies on dietary supplements for osteoarthritis in humans and identified MSM as one of six substances with a statistically significant reduction in pain.

An honest conclusion

MSM is no miracle cure. The research on horses is based on small sample sizes and short timeframes; a large-scale, peer-reviewed dose-response study on horses does not yet exist. However, the biological foundation is solid: sulphur is required to build cartilage, tendons, and connective tissue, the anti-inflammatory effect has been confirmed in several independent laboratories, and the existing equine studies consistently show positive trends with no serious side effects. So, while MSM is not a panacea, it is a valuable building block. And it becomes particularly beneficial when it doesn't have to work alone.

MSM dosage for your horse: How much does your horse really need?

In the published equine studies, dosages ranged between 8 mg/kg of body weight (Marañón et al.) and 21 g per day (Barshick et al.). The most common recommendation derived from this is around 10 to 20 g of MSM per day for a 500 kg horse when MSM is given as a pure, standalone active ingredient.

To get started, many experts recommend an initial loading phase: feeding double the amount for the first two to four weeks, and then reducing to the normal maintenance dose. This makes perfect sense, as MSM does not have an immediate effect. Experience shows that it takes at least 8 to 12 weeks of consistent feeding until a reliable picture emerges. Many report the first changes after four to six weeks, but patience is key here.

Now it gets interesting: if MSM is used in a well-balanced combination product – meaning alongside glucosamine, collagen, and hyaluronic acid – the individual dosage can be set lower without losing effectiveness. We'll explain exactly why in a moment.

What you should look out for when buying: many joint products list MSM in their ingredients without revealing exactly how much it contains. EU Regulation 767/2009 permits this, as manufacturers only have to list ingredients in descending order of their weight percentage; specific quantities per kilogram are voluntary. So, if a product says "MSM" but provides no mg/kg figure, you simply don't know whether your horse is getting an effective dose or merely a trace amount for advertising purposes. As a consumer, you should therefore actively look for products that openly declare their active ingredient quantities.

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

Joints are complex systems. Cartilage, synovial fluid, ligaments, and tendons all have different requirements, which is exactly why it makes sense to combine active ingredients that target different areas. Imagine a joint like a house again:

• Glucosamine (50,000 mg/kg in nuvallo move) is the building material for the filling. It is converted in the body into glycosaminoglycans, the molecules that make cartilage elastic and resilient. MSM provides the sulphur the body needs to build cartilage from glucosamine in the first place – two keys to the same lock.
• Collagen (85,000 mg/kg in nuvallo move) is the scaffolding. It gives connective tissue, tendons, and cartilage their structure and tensile strength. While MSM and glucosamine provide the filling, collagen ensures the whole structure holds together.
• Hyaluronic acid (5,000 mg/kg in nuvallo move) is the lubricant. As the main component of synovial fluid, it ensures smooth movement. In-vitro studies from Ohio State University (Kilborne et al., 2017) show that hyaluronic acid combined with glucosamine has a stronger anti-inflammatory effect than when used alone – an indication of genuine synergy.
• MSM (75,000 mg/kg in nuvallo move) provides organic sulphur, has an anti-inflammatory effect, and protects the tissue from oxidative stress.

A randomised, placebo-controlled crossover study by the Animal Health Trust in Newmarket (Murray et al., Equine Veterinary Journal) demonstrates that combination products do work. 24 horses, 71% of them with mild to moderate lameness, were given either a combination supplement containing glucosamine, chondroitin sulphate, and MSM, or a placebo for 21 days each. The horses on the supplement showed significantly reduced degrees of lameness and better mobility. Because each horse served as its own control, the result is particularly telling.

Although a combination study cannot tell us exactly how much each individual ingredient contributes, the overall picture is clear: a well-balanced combination product does not require extreme individual dosages because the active ingredients complement each other. This is precisely the principle we use in nuvallo move. One daily ration (6 snacks for a 500 kg horse) transparently provides 2,250 mg of MSM, 1,500 mg of glucosamine, 2,550 mg of collagen, and 150 mg of hyaluronic acid.

Feeding MSM to your horse: The biggest problem isn't the active ingredient

Now we come to the point that hardly anyone talks about, but which makes the biggest difference in practice.

MSM has a slightly bitter, sulphurous taste. Barely noticeable to us, it's a real issue for the sensitive equine nose. And this is exactly where the dilemma begins. You buy a high-quality joint powder, read the recommended dosage, and conscientiously mix the correct amount into the feed. And then? Your horse sniffs it, pushes the feed back and forth, eats half, and leaves the rest. Or it eats everything, but a fine, slightly sticky layer remains at the bottom of the trough – precisely the layer where the powder has settled.

You know the usual tricks: introduce it slowly, dampen it, mix it into sugar beet pulp, stir it up with apple sauce. Sometimes this works, sometimes it works for a while, and sometimes absolutely nothing helps because your horse is simply cleverer than any trick. The frustrating part isn't the effort, but the uncertainty: has your horse really taken in the full dose? Or is the expensive supplement seeping away in the trough, leaving you paying for a clear conscience instead of real results? We know this feeling; we have stood at the feed trough often enough ourselves wondering exactly the same thing.

Why we did away with powder

After years with our own horses and speaking with hundreds of horse owners, we eventually flipped the question. Not "How do we make a better powder?", but rather "How do we ensure that every horse reliably takes their full dose?" The answer was nuvallo move, a functional joint snack that is fed directly from the hand.

Each snack contains a defined amount of glucosamine, collagen, MSM, and hyaluronic acid. Six snacks per day make up the daily ration for a 500 kg horse. No weighing, no dust, no mixing. The horse cannot sort anything out, as the active ingredients are baked right into the snack rather than sprinkled on top. And instead of stress at the feed trough, your horse experiences feeding as what it should be: a reward. The base is free from wheat and corn, relying on linseed cake and rice bran, which makes it suitable even for horses with sensitive stomachs. Natural ingredients such as banana, apple, and carob ensure a level of acceptance that no powder can offer.

Because ultimately, the best supplement isn't the one with the longest ingredient list or the highest laboratory values. It is the one that actually gets into the horse.

Frequently asked questions about MSM for horses

How long does it take for MSM to work in a horse?

The first noticeable effects typically appear after 2 to 4 weeks of consistent daily feeding. Riders often report more fluid movements, an improved suppling phase, and faster recovery after training. For a fair assessment of the overall effect, however, you should feed it continuously for at least 8 to 12 weeks, as the metabolism of connective tissue and cartilage is slow. Daily administration is important, because skipping weekends or irregular feeding will significantly delay the effects.

When should you feed MSM?

MSM makes sense in several situations: in daily training to support recovery after exercise, especially for sports and competition horses; in older horses to maintain mobility; as well as after operations or during box rest, when the connective tissue is particularly challenged during the rehabilitation phase. The daily dose is best given in the morning or evening with their hard feed; regularity is what matters, not the exact time of day. During acute phases or at the start of a course, a double dose is recommended for the first 2 to 3 weeks to replenish the body's reserves.

What is MSM used for in horses?

MSM is not a medication and does not replace veterinary treatment following a diagnosis. As organic sulphur, it is an essential building block for connective tissue and supports the body's own regulation of inflammation. In practice, it is primarily used for the nutritional support of the musculoskeletal system: during high athletic exertion, to aid recovery after training, to maintain mobility in older horses, and generally to supply tendons, ligaments, and cartilage with sulphur. In the case of specific health issues, it is always best to discuss feeding with your vet; MSM then acts as one component in your overall management plan, not as a standalone solution.