Silicon in Horse Feeds: Joint Health & Coat Quality

Why Silicon Matters for Your Horse

When horse owners think about minerals, calcium, phosphorus, and zinc usually spring to mind. Rarely does silicon get a mention — yet this humble trace element plays a surprisingly important role in your horse's connective tissue, skeletal development, coat quality, and hoof integrity.

Silicon (Si) is the second most abundant element in the Earth's crust, and it's present in many of the forages and grains your horse eats every day. Despite this abundance, it's often overlooked in equine nutrition discussions. In this article, we'll explore what silicon actually does in your horse's body, where it's found in the diet, and how to make sure your horse is getting enough to support healthy joints, a gleaming coat, and strong hooves.

What Is Silicon and How Does It Work?

Silicon is a non-metallic trace element. In nutrition, we're primarily interested in bioavailable forms of silicon — specifically orthosilicic acid, the form that can be absorbed from the gut and used by the body.

Once absorbed, silicon concentrates in connective tissues — the cartilage, tendons, ligaments, bones, skin, hair, and hooves. It's involved in the cross-linking of collagen and glycosaminoglycans (GAGs), which are the structural building blocks of these tissues. In simple terms, silicon helps your horse's body build and maintain the "scaffolding" that holds joints together, gives bones their flexibility, and makes the coat and hooves strong.

Silicon's Role at the Cellular Level

Research in both human and animal models has shown that silicon:

• Stimulates collagen synthesis — Collagen is the most abundant protein in connective tissue. Silicon is required for the enzyme prolyl hydroxylase, which is essential for proper collagen formation.
• Supports glycosaminoglycan production — GAGs like chondroitin sulphate are critical components of cartilage and joint fluid. Silicon is needed for their synthesis and structural integrity.
• Aids bone mineralisation — Silicon has been shown to be present at the active calcification sites in growing bone, suggesting it plays a direct role in how minerals are deposited into the bone matrix.
• Contributes to keratin structure — Keratin is the protein that makes up hair and hoof horn. Adequate silicon supports the structural integrity of these tissues.

Silicon and Joint Health in Horses

Joint health is a primary concern for performance horses, ageing horses, and breeds predisposed to developmental orthopaedic conditions. While glucosamine and chondroitin supplements dominate the joint-support market, silicon works upstream of these compounds — it supports the body's own ability to produce the cartilage and connective tissue that keeps joints healthy.

How Silicon Supports Cartilage

Articular cartilage — the smooth, shock-absorbing tissue that lines joint surfaces — is made primarily of collagen and proteoglycans (which contain GAGs). Silicon is involved in the synthesis of both. When silicon is deficient, the body's ability to repair and maintain cartilage may be compromised.

Studies in other species (particularly poultry and rats, which have been the primary models for silicon research) have demonstrated that silicon deficiency leads to:

• Thinner, less resilient cartilage
• Reduced collagen content in connective tissues
• Abnormal bone development

While large-scale controlled studies specifically in horses are still limited, the biochemical pathways are conserved across species, and many equine nutritionists now recognise silicon as a valuable component of a joint-support strategy.

Supporting Horses with Osteoarthritis

For horses with degenerative joint disease or osteoarthritis, ensuring adequate silicon intake may help support the body's natural repair processes. Silicon won't reverse existing damage, but it can contribute to an environment where the body has the raw materials to maintain cartilage and joint fluid as effectively as possible.

It's worth noting that silicon works best as part of a comprehensive approach — alongside appropriate exercise management, anti-inflammatory support where needed, and a well-balanced diet that also provides adequate copper, zinc, and manganese (all of which are also involved in connective tissue metabolism).

Silicon for Coat Quality and Skin Health

A glossy, healthy coat is often the first thing people notice about a well-nourished horse. While omega-3 fatty acids, biotin, zinc, and copper tend to get the headlines, silicon quietly contributes to coat quality behind the scenes.

Silicon is found in relatively high concentrations in skin and hair. It contributes to:

• Hair shaft strength and elasticity — Silicon supports keratin cross-linking, making individual hairs stronger and less prone to breakage.
• Skin integrity — As a component of the connective tissue in the dermis (the deeper skin layer), silicon helps maintain skin elasticity and resilience.
• Coat sheen — A well-structured hair shaft reflects light more uniformly, which is what gives a healthy coat that characteristic shine.

Horse owners who supplement silicon often report improvements in coat texture and shine within a few weeks to months, although it's important to remember that coat quality is influenced by many nutritional and non-nutritional factors.

Silicon and Hoof Health

Hoof horn is made of keratin, and silicon's role in keratin cross-linking makes it relevant to hoof quality as well. Horses with weak, crumbly, or slow-growing hooves may benefit from ensuring their silicon intake is adequate.

Silicon works alongside other key hoof nutrients:

• Biotin — Supports keratin production
• Zinc — Required for keratin synthesis enzymes
• Copper — Essential for cross-linking of keratin and collagen
• Methionine — An amino acid that provides sulphur for keratin bonds

No single nutrient is a magic bullet for hoof health. Silicon is one piece of a larger nutritional puzzle, and its benefits are most apparent when the rest of the diet is also well balanced.

Where Does Silicon Come From in Your Horse's Diet?

The good news is that silicon is naturally present in many common equine feedstuffs. The challenge is that silicon content varies widely depending on the plant species, soil conditions, and how the feed has been processed.

Natural Sources of Silicon for Horses

Bioavailability Matters

Not all silicon in feed is equally available to your horse. Much of the silicon in plants is bound in phytolithic (plant stone) form, which is poorly absorbed. The bioavailability of silicon from different sources can range from less than 1% to over 50%, depending on the chemical form.

This is why some horses on apparently silicon-rich diets may still benefit from supplementation — the silicon they're consuming may not be in a form their gut can efficiently absorb.

How Much Silicon Does a Horse Need?

Unlike minerals such as calcium or phosphorus, there is no universally agreed NRC (National Research Council) requirement for silicon in horses. This is partly because silicon deficiency is difficult to diagnose definitively, and partly because research in horses specifically is still catching up.

However, based on extrapolation from other species and the available equine research, many nutritionists suggest that a horse in moderate work may benefit from 50–100 mg of bioavailable silicon per day as a supplemental dose, on top of what they receive naturally from forage and feed.

Some commercial joint and coat supplements now include silicon — often in the form of orthosilicic acid, sodium zeolite, or silicon-rich herbal extracts like nettle or horsetail (Equisetum).

A Note on Horsetail (Equisetum)

Horsetail is one of the most silicon-rich plants on the planet and is a traditional herbal source of silicon. However, some species of Equisetum contain the enzyme thiaminase, which destroys vitamin B1 (thiamine) and can cause serious neurological problems in horses if consumed in large quantities. If you choose to use horsetail as a silicon source, make sure you use a product that has been properly processed to deactivate thiaminase, and follow dosage guidelines carefully.

Signs Your Horse Might Benefit from More Silicon

Because silicon deficiency doesn't produce dramatic, easily identifiable symptoms in the way that, say, selenium or calcium deficiency does, it can be tricky to spot. However, the following signs might suggest your horse's silicon intake is suboptimal:

• Dull, dry, or brittle coat that doesn't respond to other dietary improvements
• Slow hoof growth or hooves that are prone to cracking and crumbling
• Joint stiffness or early-onset joint issues, particularly in young or athletic horses
• Poor wound healing or skin that seems slow to recover from minor injuries
• Weak connective tissue — horses that seem prone to tendon and ligament injuries

Of course, all of these signs can have multiple causes. The key is to look at the whole picture, including the rest of your horse's diet, workload, age, and health status.

How to Optimise Silicon in Your Horse's Diet

Here are some practical steps you can take:

1. Start with Good Forage

Grass hay and fresh pasture are your horse's primary natural sources of silicon. Ensuring your horse has access to quality grass-based forage is the foundation.

2. Consider the Whole Diet

Silicon doesn't work in isolation. Its benefits for joints, coat, and hooves are maximised when the rest of the diet is balanced — particularly copper, zinc, manganese, and biotin. If you're unsure whether your horse's diet is meeting all of their trace mineral needs, analysing your horse's diet is an excellent first step. A thorough analysis will highlight any gaps or excesses that might be undermining your horse's health.

3. Choose the Right Supplement Form

If you decide to supplement silicon, look for products that provide it in a bioavailable form. Orthosilicic acid (sometimes stabilised with choline) is one of the most studied and well-absorbed forms. Silicon from zeolite or processed plant extracts can also be effective, depending on the product.

4. Be Patient

Connective tissue turnover is slow. It can take 3–6 months of consistent supplementation before you see visible improvements in coat quality or hoof growth. Joint benefits may be even subtler and take longer to become apparent.

5. Don't Over-Supplement

Silicon is generally considered very safe, with a wide margin between effective and toxic doses. However, as with any supplement, more is not necessarily better. Stick to recommended doses and don't assume that doubling up will produce faster results.

Silicon in Context: Part of a Bigger Picture

Silicon is not a miracle mineral. It won't single-handedly transform a dull coat into a show ring shine, or cure arthritis in an ageing horse. But as part of a well-considered, balanced nutritional programme, it plays a genuinely useful role — one that's been under-appreciated in equine nutrition for too long.

The growing body of research into silicon's role in connective tissue biology is encouraging, and as more equine-specific studies emerge, we're likely to see clearer guidelines and greater recognition of this trace element's importance.

For now, the practical takeaway is simple: make sure your horse's diet includes good-quality grass forage, ensure the broader mineral profile is balanced, and consider a bioavailable silicon supplement if your horse shows signs of suboptimal connective tissue health. Your horse's joints, coat, and hooves may thank you for it.

Key Takeaways

• Silicon supports collagen and GAG synthesis, which are essential for healthy joints, cartilage, skin, coat, and hooves.
• Grass-based forages are the best natural dietary sources of silicon for horses.
• Bioavailability varies widely — not all dietary silicon is equally well absorbed.
• Silicon works best as part of a balanced diet, alongside copper, zinc, manganese, biotin, and other key nutrients.
• Supplementation should use bioavailable forms like orthosilicic acid, and results may take several months to become visible.
• Always assess the whole diet before adding individual supplements — a balanced foundation makes every nutrient work more effectively.