I prefer the Dasuquin because it has avocado added to the traditional mix of glucosamine and chondroiten.  I buy the formula that also has MSM.  Some studies have shown that the addition of avocado makes the other elements work better.  I doubt that there is shellfish in it because there is no mention of green-lipped mussel but you could call the Nutramax company to make sure (1-800-925-5187).  This product is guaranteed to have at least 99% active glucosamine.  Many over-the-counter products are cheaper because they do not test actual levels.  Consumer Reports has shown that many glucosamine products contain only up to 20% of active drug.

It wouldn't hurt to start anytime. I know that Trouble has allergies and the tabs I use do have liver flavor but I think they also make an unflavored capsule.  You could also consider adding Adequan injections. The bottle is labelled for IM injections but you can also do SQ and get the same benefits (your vet can show you how).  The typical regimen is 1 injection twice weekly for 4 weeks then reduce to once monthly.  I have Loki on both Dasuquin and Adequan for his shoulders and that keeps him comfortable.

Pam

Interesting about the shellfish; I'm glad that you called them.  I wasn't sure if Loki would handle it okay since he has pretty bad food allergies but he has done well with it.  I hope that it helps Trouble feels better!

Pam