I have a 10 year old who was slowing down dramatically due to arthritis. I have a thread about him that has many good suggestions you should read here:
Adequan worked wonders
for him, but it took about 3 weeks into the loading dose (2X per week for four weeks) to see an improvement. Then we scaled back to 1X per week for a 2 weeks, then down to every other week, which is where we are now. I wish I had known about it long ago.
He also gets supplements that are similar to what you are giving, plus a few more you might want to consider:
1. natural eggshell membrane supplement (FastJoint+ brand, available at Drugstore.com)--see the thread linked above for the recommendation about this,
2. Type II cartilage supplement (available at Whole Foods, or online)--again, see the prior thread about this, as you can potentially make this yourself with chicken bone broth
3. Ester-C (there is some research on it is that is promising
5. 4000 mg of fish oil (natural anti-inflammatory)---I think the key is to give a big enough dose, so that it's a therapeutic dose, instead of just nutritional support. We worked our way up from 2000 mg. to 3000 and now 4000 (too much too fast can upset the stomach).
6. vitamin e (mixed tocopherol), due to the large fish oil dose
7. Prozyme (digestive enzyme, with Bromelain, a natural anti-inflammatory)
We've been so successful that we've faded the Carprofen/Rimadyl nearly away (though he does still get some Gabipentin, as the vet wants to avoid a pain-recurrence syndrome, and Gabipentin is much safer than the NSAIDs). I also keep the Carprofen on hand in case my guy has a bad day, but he's doing very, very well.
After a couple of months of this, he is asking to jog again when we go on our walks. His gait is so much faster than it was, it's almost unbelievable. He no longer moves like an old guy. At the socialization field, he is playing "chase" again with the other dogs. Last week, he ranpretty hard with the other dogs, and it made my heart smile to see him doing that again. He wasn't doing any of this 6 months ago--he was slowly walking around the field, staying very close to me and not running at all. He's feeling good
I hope you see the same Adequan results. I can't say how much of my results are Adequan, and how much are supplements. My vet thinks it's all intertwined. All I know is it's working, and it's totally worth the expense.