I give my old boy CBD paste. He has both arthritis and sundowners . I am in the Facebook group Herbal Health Pets. They are very knowledgeable. There is a recipe for home made golden paste on there. I think there is a lot of CBD oil on the market now that isn't the best quality, eg Holland and Barrett.
There are two kinds of CBD, sativa and indica. I get mine from The Original Alternative. The green oil or paste (sativa) is the best for arthritis pain relief as it's also got good anti inflammatory properties. I give my dog purple paste which is a mix of the two as it helps with his anxiety in the evening.
Another thing to consider is CBD should be introduced gradually, it doesn't work like a conventional drug and can take about three weeks to notice a difference.
Hope this is helpful for you.
Val