I really have no idea. I've never heard about using black pepper with turmeric, but that doesn't mean anything, as I'm not nearly as familiar with herbals as I am with actual vitamins and minerals. I would like to learn more about herbals, but haven't gotten there yet.
If there's a health food store near you, you may want to ask the proprietor. They're usually pretty knowledgeable about the products they sell and how they work. In your research, did you see anything that indicated if black pepper is safe/not safe for dogs (short or long term)?
As I'm thinking about it . . . . you may want to skip the black pepper to start and see how things go. You can always then add it in (e.g. use a supplement that includes it) later if you think they need it. That way, if for some reason one of the boys has a problem with the supplement, you can already rule out black pepper as a problem. But that's really your call -- you know them, and what they can handle, better than I do. I tend to be a "keep it simple" type of person, esp. when it comes to our pets. Just my
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