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Does Glucosamine for Horses Have Side Effects?

Frederic Bousquet

Glucosamine is a popular choice for horse owners looking to maintain their horse’s bone health or treat joint pain, but many owners wonder whether or not this supplement has side effects. We reveal what you need to know about this sugar compound.

Why Supplement with Glucosamine?

As a horse ages, the rate at which its body produces glucosamine slows down. When the body no longer produces the amount of glucosamine needed for the building of cartilage, existing cartilage starts to break down.

Without cartilage to cushion the joints, pain and stiffness are the result. Glucosamine supplements for horses provide the protection and nutrients that horses’ joints need.

A Different Kind of Sugar

You may be familiar with fructose, glucose, and other pure sugars, but glucosamine isn’t any of these. Unlike other sugars, glucosamine is naturally occurring. Combined with amine, it is a nitrogen compound. Therefore, glucosamine is referred to as an amino sugar.1

What Can Occur with Glucosamine Supplementation

Shortly after starting supplementation with glucosamine, horse owners should expect the following to occur.

Joint Tissue Turnover

Equine joint tissues undergo continual rebuilding, which is called joint turnover. In healthy joint turnover, there is a consistent balance between the degradation and rebuilding of joint tissues.

beautiful brown horses in the field

In order to form the protein bonds necessary for tissue strength and repair, an essential molecule called glycosaminoglycans, or GAG, is needed. Glucosamine helps to create these GAGs, resulting in increased joint tissue turnover.

Reduced Osteoarthritis Risk

Osteoarthritis is a debilitating disease characterized by the degradation of joint cartilage. The condition causes inflammation in the joints, as well as reduced performance and decreased mobility.

Osteoarthritis is considered to be irreversible once clinical signs like the following are detected:

  • Pain in the form of lameness
  • Swollen joints
  • Stiffness at the beginning of exercise that progresses to mobility
  • Reluctance to jump or perform other painful activities
  • A decrease of range of motion in the joint
  • Lameness or stiffness in cold and damp conditions 2

Glucosamine can help in the recovery of lost cartilage and joint tissue in osteoarthritis, as well as prevent the condition from developing.


Many owners wonder whether supplementing with high doses of glucosamine will be toxic to their horse.

Young beautiful girl hugs horse at nature.

Studies in dogs and cows revealed toxic effects when glucosamine was administered in high doses. These effects included decreased joint tissue turnover and decreased cell viability.

However, it’s important to note that the glucosamine levels in these studies were far above the levels a horse would receive via supplements or even from their vet. In fact, studies have shown that glucosamine supplementation in horses showed no toxicity, even when administered at twice the recommended amount for 30 days.3


There are many glucosamine combinations available on the market. Where these are concerned, it’s important to ensure that they contain a therapeutic dose of each active ingredient. Otherwise, they will have no beneficial effects.

Another important consideration is that, although several ingredients can be beneficial to horse joint health, either by building tissue or for their anti-inflammatory properties, this may only apply when given in certain doses. Should the dosage level be exceeded, these ingredients can become harmful.

Glucosamine can help relieve your horse of joint pain, swelling, and reduced mobility. Before starting supplementation with any natural substance, it’s important to consult your vet to ensure your horse will get the maximum benefit.

Premium Quality Equine Supplements

glucosamine hci equine supplements

If you’re looking to support your horse’s joint health, glucosamine can be a great choice. Equi-Herbs loves horses as much as you do; that’s why you’ll find nothing but 100% natural ingredients in our Glucosamine HCI.

All of our products contain ingredients that we’ve hand-picked from the best sources around the world. Visit our website or call to learn more about our performance, metabolic and aid series, as well as our individual natural products: 1-800-786-0708.