What is the difference between the various forms of glucosamine?

    Written by:
    Giulia Guerrini

    Fact-checked

    by:

    Nick Milazzo
    Last Updated: May 16, 2025

    Glucosamine hydrochloride is the most common supplement form, but it may be less effective than glucosamine sulfate, which is more bioavailable and has slower clearance from the body. Additionally, a patented glucosamine sulfate/sodium chloride complex exists, but its efficacy compared to that of glucosamine sulfate remains uncertain and requires further research.

    Glucosamine hydrochloride (glucosamine HCl) is the most common form of glucosamine found in supplements. However, studies using glucosamine HCL have reported mostly nonsignificant results, suggesting that this form may not be as effective as other forms, particularly glucosamine sulfate.[1][2]

    In comparison, glucosamine sulfate is thought to be more bioavailable when taken orally and has a reduced clearance from the body compared to glucosamine HCL.[3]

    There is also a form of glucosamine available as a glucosamine sulfate-sodium chloride complex, with a 2:1:1:2 ratio of glucosamine:sulfate:chlorine:sodium. This formulation, patented by Rottafarma in Germany, is designed to be taken once a day; it is sometimes referred to as the “Rotta formulation”.[4] One study compared the pharmacokinetics of the Rotta formulation and glucosamine sulfate, and found no significant difference.[5] In terms of its efficacy, it’s still unclear whether this glucosamine sulfate salt complex is any more effective than glucosamine sulfate, and further research is needed to determine their comparative efficacy.