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Ten most common questions we vets are asked about joint supplements

1. How do I know what’s actually in a joint supplement?

If you have ever tried to find out what is in a particular joint supplement you may have found it to be a bit of a minefield, as levels of ingredients are often not stated on product packaging and brand websites may disguise everything behind marketing spiel.  This is particularly true when trying to ascertain the quantities of those all-important Omega-3’s, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).

Many brands make it actively difficult to ascertain their ingredient profile and only provide quantification of the nutrition source rather than the composition. A good example of this includes green lipped mussel (GLM), which is often included in joint nutraceuticals as a source of Omega-3. It is important to note that 100mg of GLM does not equate to 100mg of Omega-3. In fact, as little as 1.8% of GLM is considered to contain Omega-3 fatty acids1. The same principle applies to fish oil and krill oil, as these can vary in their Omega-3 content. Given that the evidence for Omega-3 fatty acid supplementation is centred around EPA and DHA availability, it is important that we know if a product actually contains these ingredients and also how much it contains.

  1. Hielm-Björkman, A. (2007). Assessment of chronic pain and evaluation of three complementary therapies (gold implants, green lipped mussel, and a homeopathic combination preparation) for canine osteoarthritis, using randomized, controlled, double-blind study designs. Page 33, content of a 100% GLM product, typical analysis.


2. Why are specific types of Omega-3 fatty acids (EPA, DHA) important?

There are many types of Omega-3 fatty acids, of which EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the most important to joint health. EPA and DHA have been shown to reduce the expression and activity of inflammatory enzymes1,2. Their action is thought to be synergistic with non -steroidal anti-inflammatory drugs (NSAIDs)3,4. This makes them useful in conditions with inflammatory components, such as osteoarthritis.

  1. Massaro, M., Habib, A., Lubrano, L., Del Turco, S., Lazzerini, G., Bourcier, T., Weksler, B. B., & De Caterina, R. (2006). The omega-3 fatty acid docosahexaenoate attenuates endothelial cyclooxygenase-2 induction through both NADP(H) oxidase and PKC epsilon inhibition. Proceedings of the National Academy of Sciences of the United States of America, 103(41), 15184–15189.
  2. Li, X., Yu, Y. and Funk, C.D. (2013). Omega 3 polyunsaturated fatty acids modulate cyclooxygenase‐2 induction via interactions with GPR120. The FASEB Journal, 27: 813.7-813.7.
  3. Miranda-Lara, CA, Ortiz, MI, Rodríguez-Ramos, F, Chávez-Piña, AE. Synergistic interaction between docosahexaenoic acid and diclofenac on inflammation, nociception, and gastric security models in rats. Drug Dev Res. 2018; 79: 239– 246.
  4. Fritsch, D. A., Allen, T. A., Dodd, C. E., Jewell, D. E., Sixby, K. A., Leventhal, P. S., Brejda, J., & Hahn, K. A. (2010). A multicenter study of the effect of dietary supplementation with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis. Journal of the American Veterinary Medical Association, 236(5), 535–539.


3. Which source of Omega 3 is better – fish oil, krill oil or green lipped mussel?

There are three marine sources of Omega-3; fish oil, krill oil and green-lipped mussel (GLM). In a canine model of cartilage degradation, fish and krill oil demonstrated superior efficacy in comparison to GLM, for their protective effect against collagen and proteoglycan degradation1.

  1. Buddhachat, K., Siengdee, P., Chomdej, S., Soontornvipart, K., & Nganvongpanit, K. (2017). Effects of different omega-3 sources, fish oil, krill oil, and green-lipped mussel against cytokine-mediated canine cartilage degradation. In vitro cellular & developmental biology. Animal, 53(5), 448–457


4. What is the role of glucosamine and chondroitin?

Glucosamine and chondroitin sulfate work synergistically to support cartilage and synovial fluid health. They contribute to the synthesis of glycosaminoglycans and proteoglycans – the building blocks of cartilage.

Glucosamine regulates the synthesis of collagen in cartilage and chondroitin inhibits destructive enzymes in joint fluid and cartilage1,2,3. Glucosamine and chondroitin can be absorbed in as little as two hours2.

  1. Bali, J.P. et al. (2001). Biochemical basis of the pharmacological action of chondroitin sulfate on the osteoarticular system. Arthritis and Rheumatism, 31(1): 58-68.
  2. Beale, B. S. (2004). Use of nutraceuticals and chondroprotectants in osteoarthritic dogs and cats. The Veterinary clinics of North America. Small animal practice, 34(1), 271–viii.
  3. Chan, P. et al. (2005). Glucosamine and chondroitin sulfate regulate gene expression and synthesis of nitric oxide and prostaglandin E2 in articular cartilage explants.


5. What is the difference between crystalline glucosamine sulphate and glucosamine hydrochloride and which is better?

Crystalline glucosamine sulfate consists of glucosamine, sulfate, sodium and chloride ions in a specific stoichiometric ratio1. Another salt form of glucosamine, is glucosamine hydrochloride. Crystalline glucosamine sulfate has demonstrated improved bioavailability (absorption)1,2 compared to glucosamine hydrochloride (the form often found in joint supplements). Crystalline glucosamine sulfate is available both systemically3 and within joints4 and has demonstrated a reduction in arthritic symptoms5.

  1. Bhathal, A., Spryszak, M., Louizos, C., & Frankel, G. (2017). Glucosamine and chondroitin use in canines for osteoarthritis: A review. Open veterinary journal, 7(1), 36–49.
  2. Meulyzer, M., Vachon, P., Beaudry, F., Vinardell, T., Richard, H., Beauchamp, G., & Laverty, S. (2008). Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulphate or glucosamine hydrochloride. Osteoarthritis and cartilage, 16(9), 973–979.
  3. Persiani, S., Roda, E., Rovati, L.C., Locatelli, M., Giacovelli, G. and Roda, A. (2005). Glucosamine oral bioavailability and plasma pharmacokinetics after increasing doses of crystalline glucosamine sulfate in man. Osteoarthritis Cartilage, 13(12), 1041-1049.
  4. Persiani S, Rotini R, Trisolino G, Rovati LC, Locatelli M, Paganini D, Antonioli D, Roda A. (2007). Synovial and plasma glucosamine concentrations in osteoarthritic patients following oral crystalline glucosamine sulphate at therapeutic dose. Osteoarthritis Cartilage. Jul;15(7):764-72. Epub 2007 Mar 13. PMID: 17353133.
  5. Herrero‐Beaumont, G., Ivorra, J.A.R., del Carmen Trabado, M., Blanco, F.J., Benito, P., Martín‐Mola, E., Paulino, J., Marenco, J.L., Porto, A., Laffon, A., Araújo, D., Figueroa, M. and Branco, J. (2007), Glucosamine sulfate in the treatment of knee osteoarthritis symptoms: A randomized, double‐blind, placebo‐controlled study using acetaminophen as a side comparator. Arthritis & Rheumatism, 56: 555-567.


6. Why do some products use loading phases and others don’t?

Traditional joint supplements often recommend administering twice the amount for the first 4-6 weeks. For some products, this may require owners to administer as many as 8 tabs a day to their dog during this period! This can increase the cost to the pet owner and create compliance concerns, particularly as joint nutraceuticals are often used in conjunction with medical therapies.

The concept behind ‘loading’ is to achieve higher uptake of the ingredients (in particular glucosamine and chondroitin), however there is a paucity of evidence to support this concept1. It may be that some manufacturers recommend loading in an attempt to mitigate the poorer bioavailability of glucosamine in its hydrochloride form1 or because there are lower levels of other active ingredients. Glucosamine in a crystalline glucosamine sulfate is considered to have better bioavailability1,2.

  1. Bhathal, A., Spryszak, M., Louizos, C., & Frankel, G. (2017). Glucosamine and chondroitin use in canines for osteoarthritis: A review. Open veterinary journal, 7(1), 36–49.
  2. Meulyzer, M., Vachon, P., Beaudry, F., Vinardell, T., Richard, H., Beauchamp, G., & Laverty, S. (2008). Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulphate or glucosamine hydrochloride. Osteoarthritis and cartilage, 16(9), 973–979.


7. Why are anti-oxidants important in a joint supplement?

Metabolic processes (e.g., inflammation) produce harmful reactive oxygen species (ROS). Inadequate control of ROS contributes to the pathophysiology of OA1. A major enzyme in the body’s anti-oxidant defence system is superoxide dismutase (SOD)2; levels of this enzyme decline with age and in patients with osteoarthritis3. Furthermore, exogenous supplementation with SOD can be beneficial in joint disease, as it has been associated with anti-oxidant activity and down regulation of inflammatory processes4,5,6,7. In addition, anti-oxidants such as SOD can help protect delicate ingredients, such as Omega-3 fatty acids from lipid peroxidation8 (i.e. going off!).

  1. Regan, E., Flannelly, J., Bowler, R., Tran, K., Nicks, M., Carbone, B. D., Glueck, D., Heijnen, H., Mason, R., & Crapo, J. (2005). Extracellular superoxide dismutase and oxidant damage in osteoarthritis. Arthritis and rheumatism, 52(11), 3479–3491.
  2. Muth, C.M., Glenz, Y., Klaus, M., Radermacher, P., Speit, G., Leverve, X. (2004). Influence of an orally effective SOD on hyperbaric oxygen-related cell damage. Free Radic Res. Sep;38(9):927-32.
  3. Scott, J.L., Gabrielides, C., Davidson, R.K., Swingler, T.E., Clark, I.M., Wallis, G.A., Boot-Handford, R.P., Kirkwood, T.B., Taylor, R.W., Young, D.A. (2010). Superoxide dismutase downregulation in osteoarthritis progression and end-stage disease. Ann Rheum Dis. Aug;69(8):1502-10
  4. Kick, J., Hauser, B., Bracht, H. et al. (2007). Effects of a cantaloupe melon extract/wheat gliadin biopolymer during aortic cross-clamping. Intensive Care Med. 33, 694–702.
  5. Vouldoukis, I., Lacan, D., Kamate C, Coste P, Calenda A, Mazier D, Conti M, Dugas B. (2004a). Antioxidant and anti-inflammatory properties of a Cucumis melo LC. extract rich in superoxide dismutase activity. J Ethnopharmacol. Sep;94(1):67-75.
  6. Vouldoukis, I., Conti, M., Krauss, P., Kamaté, C., Blazquez, S., Tefit, M., Mazier, D., Calenda, A., Dugas, B. (2004b). Supplementation with gliadin-combined plant superoxide dismutase extract promotes antioxidant defences and protects against oxidative stress. Phytother Res. Dec;18(12):957-62.
  7. Notin, C., Vallon, L., Desbordes, F., & Leleu, C. (2010). Oral supplementation with superoxide dismutase in Standardbred trotters in training: a double-blind placebo-controlled study. Equine veterinary journal. Supplement, (38), 375–381.
  8. Roginsky, V. and Barsukova, T. (2001) Superoxide Dismutase Inhibits Lipid Peroxidation in Micelles. Chemistry and Physics of Lipids, 111, 87-91


8. Are joint supplements only for older pets?

Whilst osteoarthritis is typically associated with older pets, it doesn’t exclusively affect this patient cohort. It is estimated that 1 in 5 dogs aged 1 year or older and 1 in 3 cats (aged between 2 months and 6 years) have signs of joint disease1,2.

Furthermore, supplementation with a joint nutraceutical can be considered at any age if there is a suspicion of joint disease. This may be a particularly beneficial consideration in at-risk breeds (Golden retrievers, Labradors, Rottweilers, German shepherds and other large breed dogs)3. Dogs that perform daily high-impact exercise (such as ball chasing) may also benefit from early introduction of joint supplements.

  1. Johnston S. A. (1997). Osteoarthritis. Joint anatomy, physiology, and pathobiology. The Veterinary clinics of North America. Small animal practice, 27(4), 699–723​
  2. Maniaki, E., ET AL (2021). Associations between early neutering, obesity, outdoor access, trauma and feline degenerative joint disease. Journal of Feline Medicine and Surgery. ​
  3. Anderson, K. L., O’Neill, D. G., Brodbelt, D. C., Church, D. B., Meeson, R. L., Sargan, D., Summers, J. F., Zulch, H., & Collins, L. M. (2018). Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care. Scientific reports, 8(1), 5641.


9. Can joint supplements do any harm?

Joint nutraceuticals are not typically associated with adverse effects; however, consideration should be given to the ingredient profile on nutraceuticals in patients with pre-existing conditions. This is particularly critical in conditions where nutrition is an important component in the disease management and prevention strategy.

One example of this includes the avoidance of ascorbic acid (vitamin C) in patients with a history of calcium oxalate urolithiasis (bladder stones). Ascorbic acid can cause acidification of urine, which should be avoided in these patients1 and is considered a risk factor for oxalates2.

  1. Lulich, J. P., Berent, A. C., Adams, L. G., Westropp, J. L., Bartges, J. W., & Osborne, C. A. (2016). ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats. Journal of veterinary internal medicine, 30(5), 1564–1574.
  2. Knight, J., Madduma-Liyanage, K., Mobley, J. A., Assimos, D. G., & Holmes, R. P. (2016). Ascorbic acid intake and oxalate synthesis. Urolithiasis, 44(4), 289–297.


10. Can the manufacturing process or packaging conditions damage active ingredients?

Many commercial manufacturing processes (e.g., extrusion) utilize moisture, heat and high pressures, which can have detrimental effects on delicate ingredients, such as Omega-3 fatty acids and fat-soluble vitamins (A, D, E and K). This is because these ingredients are susceptible to lipid peroxidation, which makes them less effective, rancid and therefore unpalatable. This can also occur if they are exposed to air (e.g., packaging is not resealable or airtight). Therefore, it is important to find a nutraceutical that is provided in resealable packaging and that is manufactured using methods (such as low heat, low pressure, no humidity) to ensure that these delicate active ingredients are preserved.