Glucosamine

Question

I would like to know if the supplement glucosamine is Kosher. Glucosamine has been shown to improve and keep your joints healthy. The label has a warning if you are allergic to shellfish. I asked my pharmicist about what the ingredients were. He said that it was made from the shells of crab and lobster. Would that be like the bones of an unkosher animal? As far as my pharmicist can see through research, the shells are the only way to get this supplement. Thanks, Steve with bad knees and neck!