Have used NOW Joint Support since 1992 and still walking
In 1992, from knee injuries sustained in a helicopter crash in Vietnam, my knees began clicking when walking. Although still an active soldier but not running, I was at risk of being medically boarded out of the military. I asked my orthopedic doctors what they thought about glucosamine, and they said humans cannot grow new cartilage. Well, I had read summaries of the studies and went for it. Six-weeks later there was no more clicking or since; deployed to Somalia a year later and could do light running again. Retired in 2002 still in the Infantry after deploying to Kuwait, Bosnia, and Kosovo. No limits other than regular running.