Mycosorb for Horses: Dosage Chart, Free Calculator & Safety Guide to Feed It the Right Way

Written & Reviewed By: Medshorse Team
Last Updated: October 2026

Mycosorb for horses is a yeast-based mycotoxin binder that you mix into the daily feed. The standard rate is 2 g per 100 kg of bodyweight, which works out to 10 g for a 500 kg horse. For higher-risk feed or grazing, the label rate goes up to 4 g per 100 kg (20 g for the same horse).

Here is the catch. You cannot see, smell or taste mycotoxins, and hay that looks perfect can still carry them. So most owners end up guessing at the dose and the timing.

This guide takes the guesswork out. You get a weight-based dosage chart, a free calculator, a side-by-side look at how retailers word their feeding rates, what the research on horses really shows, and the safety checks worth doing before the first scoop. Retailer details were checked in October 2026.

Disclaimer: This article is for general education and is not veterinary advice. Mycosorb is a registered trademark of Alltech. MedsHorse is not affiliated with Alltech. Always follow your veterinarian’s instructions and the current product label.

What Is Mycosorb for Horses?

Mycosorb is a feed additive made by Alltech that binds mycotoxins in the gut. It is built on glucans from the cell wall of yeast (Saccharomyces cerevisiae). Depending on the version, it also contains a small clay fraction (aluminosilicate or bentonite) and algae.

Mycotoxins are poisons made by moulds growing on pasture, hay, haylage and grain. A binder stays in the gut, holds onto them and carries them out in the manure, so less reaches the bloodstream.

It is a nutritional supplement, not a drug. The Balanced Equine product page states that it has no therapeutic effect, so it will not cure a horse that is already unwell.

Mycosorb vs Mycosorb A+: What Is the Difference?

Retail listings are not identical. Forageplus lists yeast cell wall, bentonite, chlorella and maize for Mycosorb A+ Equine. The Hoof Co lists hydrolysed yeast, hydrated sodium aluminosilicate and algae meal. Two NZ listings (Horselands and Equestrian Central) show brewers dried yeast, fermentation solubles, sodium aluminosilicate and calcium carbonate.

That suggests more than one version of the product is in circulation. Read the label on the container you actually buy, because the feeding instructions can differ too.

How Does Mycosorb Work in a Horse’s Gut?

Mycosorb works by adsorption. Toxins stick to the surface of the yeast cell wall and clay particles as feed moves through the gut, and the bound complex leaves in the manure instead of being absorbed.

Two limits matter. A binder only acts on toxins still in the gut, so it cannot undo damage already done. And no binder catches every mycotoxin equally well, which is why testing your forage still matters.

Why Do Mycotoxins Matter for Horses?

Horses are among the most sensitive animals to fumonisin, a toxin found in mouldy corn. It causes equine leukoencephalomalacia (ELEM), a brain disease that can end in death, according to the Texas A&M Veterinary Medical Diagnostic Laboratory.

The FDA guidance recommends that corn and corn by-products fed to horses stay under 5 ppm fumonisin and make up no more than 20% of the diet. That keeps the finished feed around 1 ppm.

The quieter end of the problem is just as real. In trials involving Alltech’s yeast-wall polymer, horses fed grain naturally contaminated with Fusarium toxins ate less and lost weight. Not dramatic poisoning, just a horse that stops thriving for no obvious reason.

Mycosorb Dosage for Horses: Chart by Bodyweight

Feed 2 g of Mycosorb per 100 kg of bodyweight daily as the standard dose, or up to 4 g per 100 kg when feed quality is a known concern. For a 500 kg horse that is 10 g standard and 20 g high. Both rates are quoted on Horselands, Equestrian Central and The Hoof Co listings.

Standard Rate or High Rate?

Start with the standard rate for general protection. Move to the high rate when you have a specific reason: a wet or late harvest, a new batch of hay you cannot test, or a lab result showing toxins. The Hoof Co describes the higher 4 g per 100 kg rate for affected horses.

For context, the Guelph horse trials dosed the polymer at 0.2% of the diet. A horse eating about 10 kg of feed a day would get 20 g, the same as the high rate (that conversion is my own arithmetic, not a figure from the studies).

Mycosorb Dosage by Type of Horse

• Ponies and minis: dose by weight, not by the adult scoop. A 200 kg pony needs 4 g at the standard rate.
• Foals and yearlings: guidance is thin. Forageplus lists one 10 ml scoop (about 9 g) a day, while the weight-based rule gives roughly 3 to 6 g for most young stock. Ask your vet.
• Adults in light work: 10 g for a 500 kg horse at the standard rate. Forageplus lists one 15 ml scoop (about 13.5 g).
• Moderate to hard work: Forageplus lists two 10 ml scoops (about 18 g). The Alltech-based high rate is 20 g for 500 kg.
• Breeding mares: Forageplus lists the same 18 g plan. Confirm with your vet first.

Mycosorb for Horses Calculator: Find Your Horse’s Dose

Enter your horse’s weight, pick a rate and container size, and the calculator shows the daily dose, the amount per feed and how many days the container will last.

Why Do Retailers Quote Different Mycosorb Rates?

Different retailers quote different rates because they follow different labels. Some use grams per 100 kg, others use scoops tied to workload, and the formulations are not all identical.

How to Feed Mycosorb Step by Step

1. Get an honest weight. Use a weighbridge if you can. A weigh tape is fine for planning, but it can be off by a noticeable margin.
2. Choose the rate. Standard for general protection, high for known or suspected risk.
3. Weigh the powder. A cheap kitchen scale beats a heaped scoop.
4. Mix it through damp feed. The Hoof Co advises mixing thoroughly and splitting the daily amount across meals where practical.
5. Build up gradually. Retailers advise a gradual introduction. A few days of working up to the full dose is a sensible approach for fussy eaters.
6. Keep water available. Clean drinking water should always be on hand.
7. Store it dry. Keep the container closed, cool and out of reach of children and pets.

How Long Does a Container Last, and What Does It Cost?

A 1 kg container lasts about 100 days at 10 g a day, or about 50 days at 20 g. A small pony on 4 g a day can stretch the same container to roughly 250 days.

Does Mycosorb Work? What the Research Says

The best horse-specific evidence is a pair of 2005 trials that tested Alltech's glucomannan polymer on horses fed contaminated grain. The results were encouraging in one trial and neutral on intake in the other.

Read those results with care. Both trials were short, both tested Fusarium toxins only, and the company behind the product has promoted the work. I could not find independent replication in horses.

Alltech's retailer text also cites more than 55 peer-reviewed in vivo trials, but those span dairy, beef, pigs, poultry, pets and aquaculture as well as horses. So the honest summary is: plausible mechanism, some supportive horse data, and room for more independent research.

When Should You Use Mycosorb?

Binders earn their place as an extra layer of protection when mould risk is higher than usual. Common situations include:

• Hay or haylage from a wet or late harvest
• A new batch of forage you cannot test yet
• Moving to paddocks with weeds, ergot-prone grasses or heavy tree cover
• Seasonal pasture changes, which The Hoof Co flags as a higher-risk period
• Grain or feed of uncertain storage history

When it is not the answer: visibly mouldy or dusty hay should be thrown out, not rescued with a supplement. And a horse that is already unwell needs a vet. For a clearer picture of what is actually in your forage, a laboratory mycotoxin panel will tell you which toxins are present.

Mycosorb vs Other Toxin Binders

The main binder families are yeast cell wall, clay, and blends of the two. Mycosorb A+ listings describe a blend, which aims to cover several toxin classes at once.

Is Mycosorb Safe for Horses?

Mycosorb is sold as a feed supplement and is fed daily at the label rate, but published safety data in horses is limited. I could not find overdose studies. Retailers advise staying within the stated rate unless an equine nutrition professional says otherwise.

The practical issue most owners report is palatability, which a gradual introduction handles. Beyond that, the safest approach is to follow the label and run through this checklist.

Insulin-Resistant and Laminitic Horses

Balanced Equine describes Mycosorb A+ as safe for laminitis-prone and insulin-resistant horses. Still, the ingredient list varies, and the Forageplus listing includes maize as a carrier. If your horse's insulin is being monitored, confirm with your vet.

For horses on the metformin dosage for horses protocol, a binder does not replace diet management.

Broodmares and Foals

Both Forageplus and The Hoof Co position it for breeding horses, but I found no pregnancy-specific safety trials. Talk to your vet before starting a mare, and get weight-based advice for foals.

Horses on Oral Medication

In principle, any adsorbent in the gut could bind other substances. I found no horse-specific interaction study, so ask your vet whether to space the binder away from oral medicines.

Competition Horses

The listed ingredients are common feed ingredients, but supplements are not individually approved by sport regulators. Check your governing body's rules and keep batch details on file.

Signs of a Mouldy-Feed Problem: When to Call Your Vet

Signs of mycotoxin exposure are not specific, so treat any of these as a reason to call your vet and remove the suspect feed:

• Sudden loss of appetite or feed refusal
• Unexplained weight loss or poor condition
• Colic signs
• Yellow gums or skin sores on pink, sun-exposed skin
• Emergency: stumbling, circling, head pressing, blindness or collapse (possible ELEM)

Common Mistakes to Avoid

• Feeding it to mouldy hay and hoping. Bin visibly spoiled forage.
• Guessing with scoops. Scoop weights differ between products.
• Using the adult dose for a pony or foal. Dose by weight.
• Assuming more is better. There is no published evidence that doubling the high rate adds benefit.
• Skipping the label. Versions of the product differ.
• Using it to treat illness. It is preventive, not therapeutic.

Using Mycosorb Alongside Other Supplements

Balanced Equine says Mycosorb A+ can be fed in the same feed as its mineral mixes, amino acids and other binders. In practice that means one bucket, one mix.

A few pairings come up often. A psyllium husk dosage for horses plan and a binder do different jobs (fibre for sand, binder for toxins), so they are not duplicates.

Retailers say Mycosorb barely binds minerals, so it should not undermine a magnesium dosage for horses routine, though your vet can confirm. The same goes for the kelp dosage for horses guidance.

If your horse is on ulcer treatment, such as the omeprazole dosage for horses or the sucralfate dosage for horses, ask your vet whether to space the binder away from the medication.

Final Recommendations: Should You Feed Mycosorb?

Mycosorb is a reasonable extra layer of protection if your forage or pasture carries a higher mould risk. Start at 2 g per 100 kg, move to 4 g per 100 kg when risk is clear, weigh the powder, and treat it as support, not a cure.

Your next steps: weigh your horse, plug the number into the calculator above, read your container's label, and bin anything visibly mouldy. If you have a specific worry (a sick horse, a pregnant mare, an insulin-resistant horse), bring your vet in before you start.

FAQs

Sources and Further Reading

• U.S. FDA: Guidance for Industry, Fumonisin Levels in Human Foods and Animal Feeds
• Texas A&M Veterinary Medical Diagnostic Laboratory: Fumonisin Facts
• Raymond, Smith and Swamy (2005): Fusarium-contaminated grains, feed intake, serum chemistry and hematology of horses, with a glucomannan adsorbent (AGRIS/FAO)
• Raymond, Smith and Swamy (2005): Fusarium-contaminated grains in exercised horses (AGRIS/FAO)
• Alltech (manufacturer of Mycosorb)
• Forageplus: Mycosorb A+ Equine product page
• The Hoof Co: Mycosorb A+ product page
• Balanced Equine: Mycosorb A+ product page
• Horselands: Mycosorb Toxin Binder
• Equestrian Central: Mycosorb Alltech