Uni has grade 2 LP now. She was originally diagnosed with grade 3. We put her on Cosequin (you can get it at entirely pets
Cosequin Regular Strength (90 capsules) )There is also a 180 caps size that is a bit better for the money. A bit later I took her to my new vet, and after being on Cosequin for about 1 1/2 years, she was rediagnosed at gr2. The new vet also suggested Missing Link with Glucosamine, but I found it didn't work for itching or joints, so back we went to Cosequin, and her knees seem to be popping less.
Keep in mind though, that putting your pup on glucosamine does NOT heal or treat LP, it just helps their joints be more "juicy". LP is a bone condition, where the groove in the leg is not deep enough to keep the knee cap in place. No supplement will deepen the groove in the leg. The only thing that will is surgery, but if it can be avoided, then that's what we do. Uni has been doing well, and there are a lot of pups who have grade 2 or worse that have never had surgery. Good luck!