Strongest EPA approved animal repellent rating is 2.0% Capsaicinoid
I had some that was 10%. To be fair, it was LE grade, but it did have something about repelling some "common animals, such as" and then listed some animals including dogs, bears, and apes. I thought it was hilarious that apes were common around the spray factory.
I once tried it on a dog. It was a very aggressive dog that went after anybody riding a bike on the street in front of his house. I spritzed it at the dog while trying to keep my feet up from his snapping jaws. He ran off, but not yelping in great pain like I had hoped. I turned my bike around to see what the affect had been. I then rode through the invisible left-over cloud. It stopped me. Perhaps I was the ape it referred to.