in the past I took Arthro-5 for about a year and a half, with satisfactory results. This is indeed why when recently, after about two years without Glucosamine I felt *** in the knee again, I ordered Arthro-5 again. I feel the *** in the knee less frequently but of course it remains difficult to estimate to what degree the glucosamine contributed because the period is indeed rather short (about 3 weeks). When during an appointment with my GP I showed him the Arthro-5 bottle he approved of the correct composition and advised me to keep using the product.