Glucosamine hydrochloride

About Glucosamine hydrochloride

The hydrochloride salt of glucosamine, containing more glucosamine per milligram than the sulfate salt and no stabilising sodium or potassium. It is the form used in most US products and in the large GAIT trial.

Glucosamine hydrochloride is the cheaper and, on the face of it, more concentrated form — a 1,500 mg dose delivers more glucosamine than 1,500 mg of the sulfate salt, most of which is salt. It has also performed worse in trials. The GAIT trial, the largest independent study, used the hydrochloride and found no benefit over placebo, and reviews that separate the forms consistently report weaker results for hydrochloride. Two explanations compete: either the sulfate moiety matters biologically, which some cartilage biochemistry supports, or the difference is an artefact of who funded which trials. Nobody has run the trial that would settle it.

Sold as

Tablet, Capsule, Fermentation-derived vegetarian capsule, Combination with chondroitin and MSM

Standardised to

Milligrams of glucosamine hydrochloride, roughly 83% glucosamine by weight — a product without this marker may not resemble what was studied.

Also known as

Glucosamine HCl, Vegetarian glucosamine (fermentation-derived)

Regulation: Sold as a dietary supplement in the US with no pre-market efficacy review. It is the form most commonly found on US shelves, while European prescription products use the sulfate.

What the research used

The amounts, forms and durations published trials of Glucosamine hydrochloride actually administered.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.