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An analysis of glucosamine and chondroitin sulfate content in oral joint supplement products☆

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Abstract

Oral supplements intended for the treatment and prevention of joint-related problems in horses may not contain ingredients at levels that meet label claims.

Introduction

Numerous dietary supplements containing glucosamine and/or chondroitin sulfate are marketed as a way to help support, improve or restore the health of their horse's joints. In humans, the glucosamine and chondroitin sulfate market has been estimated to be over 500 million dollars in retail sales between July 1998 and May 1999.1 While it is not clear that such products are actually effective in horses, the assessment of effectiveness might be skewed if the products did not contain content in amounts that matched label claims.

Since they are considered nutritional supplements, oral joint supplements are not subject to the same stringent requirements for quality manufacturing as are pharmaceutical products. The quality of dietary supplements becomes a question because of the lack of regulatory provisions regarding the actual content of active ingredients contained in the jar, bucket or bottle. In fact, there is no practical way for veterinarians or horse owners to judge the quality of the products that they are purchasing.

Independent analyses of a variety of supplement and herbal products designated for the human health market have shown that many products that have been tested, including calcium, St. Johns wort, ephedra and ginko biloba, have product content that fails to match label claims.2, 3, 4, 5, 6 Some even have zero active ingredients. Testingof glucosamine and chondroitin sulfate products intended for human use has also showed wide differences between published label amounts and the actual content of active ingredients.7

Even if oral joint supplement product were effective, the supplements would not be effective if the active ingredients were not included in the supplement product. This study analyzed 11 over-the-counter supplements intended for use in horses that contained chondroitin sulfate, glucosamine, or both.

Section snippets

Materials and methods

Three samples from 11 different products containing glucosamine, chondroitin sulfate, or both, were taken from off-the-shelf joint health products sold in a feed store. The samples were numbered but not otherwise identified so that the laboratories performing the testing would be blinded as to the origin of the samples and the identity of the manufacturers.

The samples were first sent for analysis of total sulfated glycosaminoglycan (GAG) content, keratin sulfate (KS) content and hyaluronan (HA)

Results

According to their labels, six products contained glucosamine, five of which contained glucosamine only (Figure 1).

. Glucosamine content of analyzed products

The average amount of glucosamine found in the product was different from that suggested by the label, with content ranging from as low as 63.6% to 112.2% of label claims.

According to their labels, six products contained CS, five of which contained CS only (Figure 2).

. Chondroitin sulfate content of analyzed products

The average amount of

Discussion

This study shows that in some instances, the amount of chondroitin sulfate or glucosamine found in over-the-counter oral joint supplement products may vary greatly from the amount reported on the label. The implications for this study are that veterinarians and horse owners may not be purchasing what they think that they are purchasing. In spite of terms such as “quality tested” appearing on labels, the fact is that there is no way to compare one product against another, or even to judge the

Acknowledgements

This project was funded by a grant from the Dolly Green Foundation.

References (12)

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Cited by (13)

  • Pharmacotherapy of joint and tendon disease

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  • Plasma Concentration of Glucosamine and Chondroitin Sulfate in Horses after an Oral Dose

    2012, Journal of Equine Veterinary Science
    Citation Excerpt :

    Degenerative joint disease and its associated joint pathology contribute significantly to musculoskeletal lameness and loss of function in performance and pleasure horses [1]. Numerous dietary supplements containing glucosamine (GlucN) and/or chondroitin sulfate (CS) are marketed as a way to help support, improve, or restore the health of horse’s joints [2]. The main goal of the medical therapy in treatment of degenerative joint disease is to restore and maintain normal joint function by alleviating pain, decreasing joint inflammation, and protecting the cartilage from further injury [3].

  • An Evidence-Based Approach to Selected Joint Therapies in Horses

    2007, Veterinary Clinics of North America - Equine Practice
    Citation Excerpt :

    Several authors have suggested that even if oral nutraceutic agents are indeed effective, it is difficult to evaluate and establish true evidence for this efficacy if the GS and CS contents of these products differ from what is claimed on their labels. A study done on 11 oral joint supplements containing GS, CS, or both analyzed the total sulfated GAG, keratin sulfate (KS), and HA contents of these products [21]. Results indicated that GS contents in 5 products containing GS only, according to their labels, ranged from 63.6% to 112.2% of label claims and that CS contents in 5 products containing CS only, according to their labels, ranged from 22.5% to 155.7% of label claims.

  • The use of nutraceuticals for osteoarthritis in horses

    2005, Veterinary Clinics of North America - Equine Practice
    Citation Excerpt :

    In testing conducted by an independent laboratory, only 50% of the products tested met the label claims [14], with many human over-the-counter products varying widely in composition [15] and more than 84% not meeting label claims [11]. In a study of five glucosamine (GLN), five chondroitin sulfate (CS), and one combination equine products [13], the actual composition of GLN was 63.6% to 112.2% of the label claim, whereas the concentration for CS ranged from 22.5% to 155.7%. In addition, the GLN content was 86% of the label claim, and the CS content was 83.3% of the label claim [13].

  • What are supplements? The importance of micronutrients in the horse's diet

    2023, Evidence Based Equine Nutrition: A Practical Approach For Professionals

  • Manual of equine lameness

    2021, Manual of Equine Lameness
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