Yes, it works for her. You know Boxer's are known for their tempermental digestive systems
We have fed the Missing Link product in the past, but switched over to the Flax Oil and I think she prefers it. Neither approach is exactly cost effective, but that's not my primary goal.
Do you use a particular ratio of the garlic powder, or just a sprinkle or two? I was disappointed that the brewers yeast and garlic tabs I used last Summer did not deter a significant flea infestation.
It was our first ever problem with fleas. Based on her overall health and beautiful coat condition, I am pretty well convinced that the assertions that parasites such as fleas and ticks are drawn only to animals in poor health is some hooey. She is an inside dog venturing outside only into my yard which has been organic since our taking over 10 years ago. Oddly enough I had allowed several fire ant beds to exist in the lawn as they are allegedly predators of fleas/ticks.