Good to hear. I put in some pretty good research into that stack when both my wife and I were suffering injuries ...
Upon cessation of glucosamine and chondroitin, symptoms may gradually come back in some folks after about the 6-month mark. However, with the addition of the niacinamide and collagen, she may be off the hook ... It's not a regimen that you really have to stop taking if they get bad again though, so that's a positive. It just takes about 6 or so weeks to really get it loaded well.
Ultimately, if she was going to be on long-term, and if she could drop glucoasmine after she loaded it for awhile and had reached a comfort level, she might be able to cruise with just the chondroitin, niacinamide and collagen as glucosamine increases insulin resistance in some folks to a degeree.
I'm glad that it worked for her ... hearing that people actually benefit from something makes doing the work of researching and posting it up worth it.