The agency claimed supporting science, provided by Merck, was "weak."
EFSA (Parma, Italy) has rejected an article 13.5 health claim for glucosamine and “the maintenance of normal joint cartilage,” following an application from Merck Consumer Healthcare. The agency’s Panel on Dietetic Products, Nutrition, and Allergies (NDA) found evidence provided to be “weak.”
Merck submitted 61 references for the health claim, including studies on healthy humans, osteoarthritis patients, and animals, and in vitro studies.
The NDA Panel concluded that the only human studies to demonstrate a beneficial effect with glucosamine were those conducted on osteoarthritis patients. Merck proposed that results from these studies could translate to healthy human subjects, but the Panel disagreed, further noting that the evidence provided for proposed mechanisms to explain glucosamine’s effect on joint cartilage was “weak.”
Merck also provided studies on glucosamine bioavailability in human and animal blood and synovial fluid. Based on these results, the Panel concluded that uptake of dietary glucosamine into cartilage cells would be very limited in humans.