This is a great article about artemisinin. While I understand that it may not work for everyone, I have seen good results from it.
Drs. Henry Lai and Narenda Singh told me that the product they most recommend is the following: Holley Pharamceuticals.
However, in the reference article above, they also recommend this: Allergy Research Group
The product I started using before contacting Drs. Lai and Narenda is this (which is suppsed to be pretty comparable to Alergy Research Group.
I had started taking this before connecting with them and got is from here: Nutricology
The Drs. inform me that artemisinin may not work for everyone, but it did for me and may be worth looking into as a complementary approach.