i've been taking glucosamine chondroitin for about 8 months now ... i used to be able to make a clicking sound just by going from an open hand to a fist ... i could do this 1,000 times in a row ... now, i can't make the sound even once ... i attribute this to increased lubrication in my joints ... i also used to have very stiff knees ... i now can crouch down without any problem at all ... so, i guess that's a recommendation to take the supplements ... fwiw, i take 1500 mg of glucomsamine and 1200 mg of chondroitin every day ... until recently, i was using a brand called: Arth-X ... i just switched to Walgreen's because it is cheaper ...
the guy who started the glucosamine craze and wrote the bestseller book called "The Arthritis Cure" is named Dr. Theodosakis ... i would highly recommend reading a little of his website:
http://www.drtheo.com/ ... the site provides lists of recommended brands and brands to stay away from ...
as to your sore knees, however, that's another matter ... the supplements may help but one has to wonder why you're having soreness ... are you just plain overdoing it? i know someone who's now had 5 major knee surgeries because of overdoing it on a StairMaster ... too much of good thing can do real damage to your knees ... it might be worth getting some diagnosis to determine what's causing the soreness ...
one thing that's very important is to ensure that you have the bike setup correctly ... at the bottom of the pedal stroke, your leg should have a very slight bend at the knee ... if your leg is totally straight or if it's very bent at the knee, you can cause serious knee problems ... check that out the next time you're on the bike ...
if i had sore knees, i would use ice to reduce inflammation ... i would also use some type of anti-inflammatory (like Aleve or Advil) and i would rest for several days or more ...
probably the best thing you could do would be to cross-train ... too much intensity with a single activity often leads to injury ... so, ride the bike one day; swim the next; do weights the next and then return to the bike ... maybe even mix in a little jogging when your knees feel better ... variety is the best way to get into shape ...
aerobic activity is a great way to lose weight and being lighter puts less strain on your knees ... but all that will be lost if you become injured or it becomes so uncomfortable that you don't want to continue ... let yourself heal ... fitness is a marathon; not a sprint ...
hope this helps ...