Glucosamine – Should you supplement?


There is little evidence that glucosamine can accomplish some of its claimed benefits in patients, particularly in terms of restoring joint cartilage or slowing the progression of arthropathies.28 There is no histological study to support this claim. Only a few randomised double-blind trials of glucosamine treatment have assessed outcomes.

 The hexose sugar structure of glucosamine might exacerbate diabetes. In animal models of diabetes, glucosamine increased insulin resistance through an unknown mechanism.

 Glucosamine is subject to a high degree of first pass metabolism, such that oral bioavailability is poor.

The half-life has been reported to vary from 28 to 58 hours.  The small percentage that survives firstpass entry into the circulation is transported by an unknown carrier in the vessels to reach the synovial joint. Any glucosamine molecules that reach the joint need to enter the cartilage. However, there are few or no blood vessels in cartilage. Therefore glucosamine molecules need to either diffuse across synovial fluid or enter via the dense bone-cartilage interface in order to arrive at the hyaline cartilage. Once there, the monosaccharide or sulphated monosaccharide needs to be reassembled into a much larger proteoglycan and GAG macromolecules, but the enzyme that performs this task is unknown.

 It is recommended that glucosamine be taken for 6 to 8 weeks before any symptom relief can be expected, but there is no evidence to support this belief. We consider that it is likely to be no more effective than a placebo.

 According to the Cochrane review, there was significant difference between glucosamine and placebo with respect to effects on pain, function, and range of movement.27 Histological analysis of the alleged benefits of glucosamine is lacking.



In short.

  • Glucosamine is not a proven science.
  • Taken orally it has low bioavailability.
  • The hyaline cartilage (the part where glusosamine supposedly helps – not all cartilage) have very little or no blood vessels hence its effects questionable. It needs to transverse via the synovial or the dense bone cartilage in order to reach the hyaline cartilage which is highly improbably
  • It has a short half-life 28-58 which means need constant usage
  • Studies suggest that it increases insulin resistance– hence you may  need to take the product in “cycles” so that you re-sensitise your insulin receptors.
  • Stabilizer for glucosamine is typically salt – especially in Sulphate form



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