I use Dr. Andreas Kalcker as a resource and he recommends chanca piedra (aka Stone Breaker) as a means of breaking up the biofilm that the parasites reside in.
So you have found an effective remedy. Destroy the biofilm with the chanca piedra and then kill them off with the garlic and chili powder.
I used bromelain for the same purpose and it worked really well. My kill rate increased dramatically.
Do you take the chanca piedra with water? On an empty stomach? All at once or through out the day?