Pet Health
Glucosamine & Chondroitin
Treatments in Dogs
Veterinary & Aquatic Services Department, Drs. Foster & Smith, Inc.

The history of glucosamine and chondroitin

Glucosamine and Chondroitin have been used to treat osteoarthritis in Europe for over
twenty years. Recently, physicians and veterinarians in the United States have begun to
prescribe this product for their patients and have been extremely happy with the results.
These products are proving to be one of the safest and best treatments for the crippling
effects of osteoarthritis that affects millions of aging dogs throughout the United States.

Despite the fact that the benefits of these glucosamine and chondroitin products have
been known for over twenty years, many people question why these products are just
now being used in the United States. The answer lies in the fact that glucosamine and
chondroitin are not products that can be patented, and therefore, offer little incentive to
the large pharmaceutical companies to develop a product. Pharmaceutical companies spend
millions in research and development and need a patented product to guarantee sales and
to recoup their investment.

Another issue is that glucosamine and chondroitin are considered nutraceuticals and are not
strictly controlled by the
FDA. They are naturally occurring substances in many food
products and fall in the same class as vitamins. Despite the overwhelmingly positive studies
done in Europe, American researchers still refused to perform controlled studies. In fact,
literature searches show that there are hardly any North American studies done on these
products. But all this is quickly changing. Because of the huge number of humans and pets
suffering from osteoarthritis and the tremendous success in the treatment of this disease
when using glucosamine and chondroitin, many companies are now producing a product line
and several broad research studies are underway.

Uses of glucosamine and chondroitin

Glucosamine products have been studied and used for the healing of skin wounds, stomach
ailments, and joint problems. Their use in the relief and healing of the symptoms of joint
disease is currently their biggest use. Glucosamine and chondroitin have been successfully
used in humans, horses, dogs, and cats. This article deals only with glucosamine and
chondroitin and their therapeutic use for osteoarthritis in the dog and cat.

There are many different joints that can be affected by osteoarthritis in the dog, but by
far, the most common is the hip joints.
Hip Dysplasia is very common in many of the larger
breeds of dogs. This condition greatly exacerbates the normal wear on the smooth cartilage
protecting the bony surface of the joint. When this cartilage wears away there is a bone to
bone contact, which creates the pain seen with arthritis. Even dogs that do not have hip
dysplasia may have a decrease in this cartilage as they age, and will show signs of arthritis.
In addition, aging dogs may also have arthritis in their knees, elbows, and shoulders and
cartilage loss or damage that respond to glucosamine and chondroitin.

Glucosamine and chondroitin are also often used as an aid in the treatment of spinal disc
injuries or post operatively in dogs that have undergone joint surgery.

The typical patient that is placed on and responds
to glucosamine and chondroitin therapy is a middle
aged to older medium to large breed dog. Dogs may
show symptoms of limping or stiffness especially in
the morning and during cold weather. They usually
loosen up as they move around and exercise. Some
dogs have difficulty climbing stairs or getting into or
out of a vehicle. Many dogs respond to treatment with buffered aspirin (
Do NOT give your
cat aspirin unless prescribed by your veterinarian
) or carprofen (Rimadyl), but when
the product is discontinued the pain and symptoms return. Osteoarthritis also affects small
dogs and cats and glucosamine and chondroitin have been used very effectively in relieving
their symptoms.

Most older dogs suffer from some level of osteoarthritis. Many owners attribute the loss of
activity to old age and may not even identify it as a problem. And they never appreciate
how much their dog’s activity level was being reduced by the arthritis until they place their
dog on glucosamine and chondroitin therapy and see the return of normal function.

Where are glucosamine and chondroitin found?

Glucosamine and chondroitin are normal substances found in the body of living animals.
They are at their highest concentration in cartilage. Unfortunately, through degradation
during digestion and processing, almost all of the glucosamine in an animal's diet is
unavailable for use. The body, therefore, synthesizes most of its own glucosamine through
a biochemical reaction utilizing glucose. In normal healthy animals the body is able to
synthesize enough glucosamine to keep the existing cartilage healthy, but when the animal
ages or there is damage to joint cartilage it cannot produce enough to keep up with the
body's needs. This is where a supplemental form of glucosamine is needed.

Supplemental glucosamine: Glucosamine is a 2-amino derivative of glucose which is
obtained through the hydrolysis of chitin, a polysaccharide found in the shell of crustaceans.
Crustaceans have a very high concentration of chitin and because the shells are often
discarded, provide a reliable and cost effective source of glucosamine.

Chondroitin: Chondroitin is a naturally occurring product found in animal cartilage.
Supplemental chondroitin is derived primarily from bovine (cow) cartilage, particularly the
cartilage rings of the trachea. It is also derived from shark and whale cartilage. The source
does not appear to have any impact on its effect. Though for ecological reasons, many
consumers prefer bovine sources.

How do glucosamine and chondroitin work?

The way that glucosamine works is a very complicated process. In a nutshell, cartilage
consists of several different cells, one of which is chondrocytes. Chondrocytes are
responsible for synthesizing new cartilage. Through normal wear, cartilage is constantly
being broken down and replaced. When a dog has hip dysplasia or ages, the chondrocytes
do not have the building blocks available to them to build enough new cartilage to keep up
with the breakdown of the old cartilage. Glucosamine provides the building blocks to
synthesize new cartilage. Glucosamine is the building block necessary for the production of
the substances called glycosaminoglycans. The glycosaminoglycans are combined with
hyaluronic acid to make the substance proteoglycans. The proteoglycans and collagen are
the main structures of cartilage.

Chondroitin also is one of the products necessary for the
synthesis of glycosaminoglycans. But it probably plays a
more important role by combating and neutralizing
destructive enzymes in the joint. There is always a low level
of destructive enzymes found in the joint, but when injury or
abnormal wear occurs, the destructive
enzymes and agents increase accelerating cartilage
destruction. When chondroitin is added to the diet it helps to reduce the level of these
destructive enzymes.

What are the side effects?

There are very few side effects.  Glucosamine and chondroitin have been used for over 20
years in Europe without any complication or listing of side effects. Occasionally, a dog will
vomit or get diarrhea with this product. If the dose is reduced or given with food, the
symptoms are usually alleviated. Once a dog begins using the product, they must stay on it
for the rest of their lives or the degeneration of the joint cartilage will return. Once the
product has promoted healing for 8 weeks, the dose is often reduced. The safety of this
product is well suited for long term use. It can also be used with most other drugs and
vitamins without any complication. The owner of any animal that is taking a medication
should always seek veterinary advice before adding any new product or drug.

Where can I get glucosamine and chondroitin?

Glucosamine and chondroitin can be found in many different forms. Glucosamine in a pure
form, or combined with chondroitin, can be purchased in health food stores, at veterinary
clinics, and in pet supply catalogs.

Not all glucosamine and chondroitin products are created equal, however. The difference in
various products lies in the dosing, carriers, vitamins, minerals, and purity of the ingredients.
Products that contain human grade glucosamine and chondroitin are much more likely to be
of high quality and in a purer form. In addition to ingredients, the concentration of actual
glucosamine and chondroitin vary from product to product. Products designed for dogs
often have ascorbic acid or manganese to help aid in the uptake of glucosamine in the
canine. Canine products may be flavored or fortified with other minerals. The most
expensive product is not always the best. Compare the ingredients between products to
ensure that you are getting what you pay for. Some of the most popular products for
canines include Drs. Foster and Smith's Joint Care, Cosequin made by Nutramax, and


Why did my vet not recommend glucosamine/chondroitin for my pet?

Many veterinarians are just becoming aware of the benefits of glucosamine and chondroitin.
Most veterinarians gain their information about new products through major pharmaceutical
companies. Because the large pharmaceutical companies are not promoting this product it
has taken longer to be introduced to veterinarians. Veterinarians that specialize in
orthopedics or who keep current on all new products are usually very aware of the benefits
of glucosamine and chondroitin and have used these products for years.

Do glucosamine/chondroitin really work?

There have been many studies done in Europe showing the benefits of these products.
There is a complete absence of completed studies on these products in the United States,
although, many are currently underway and initial reports confirm the results seen in Europe.

Can I use glucosamine/chondroitin with painkillers or other drugs?

Many animals are on aspirin or carprofen (Rimadyl) before they begin
glucosamine/chondroitin therapy. I usually encourage owners to wean their pets off of
painkillers over a period of six weeks while the glucosamine and chondroitin are taking
effect. Some animals with severe arthritis may need to be on a low dose of buffered aspirin
to maintain their comfort even with the benefits of glucosamine and chondroitin. Other
supplements such as multivitamins and fatty acids are often given to animals on glucosamine
supplements without any problems. It is always best to check with your veterinarian before
putting your pet on any medication or supplement. This information should be a part of
your pet's medical record.

What is the difference between glucosamine (HCl) and glucosamine sulfate?

Glucosamine hydrochloride (HCl) and glucosamine sulfate both work equally well in dogs.
The sulfate form was originally used in Europe. The HCl form has recently become more
popular because it is purer and provides more available glucosamine per unit weight and
contains much less residual ash.

How long can I keep my dog on it?

Most pets need to be on the replacement therapy for the rest of their lives. Studies have
shown that cartilage degeneration will reoccur about four to six months after the product is
discontinued. The exception to this would be young animals that were on it for 3 months
or so following a joint surgery or injury.

Can I use it to prevent hip dysplasia?

There is no indication that this product slows the progression of hip dysplasia. It does not
prevent the development of hip dysplasia. Many animals that have hip dysplasia benefit from
being on glucosamine and chondroitin because it helps heal the cartilage and reduce the
pain involved with this disease.

Can I give my dog the kind that I take?

Pharmaceutical grade glucosamine and chondroitin are used for humans and are found in
some veterinary products. It is perfectly safe to use human glucosamine in your pet.
Hhowever, products made for animals contain ascorbic acid to help in the uptake, in
canines. In addition, animal products are dosed in the correct size for animals and are often
flavored to make them more palatable to pets.

Can glucosamine and chondroitin be used in cats?

It is safe to use in cats and appears to work very well in
reducing the signs of feline osteoarthritis.  

Copyright © 1997-2004, Drs. Foster & Smith, Inc. All Rights Reserved.
          Reprinted from
Chondroitin blocks         
destructive enzymes
that break down            
cartilage in the joint.
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