I can give an update on my experience. First a review of the different products out there. Chaparral is the raw herb from the desert plant that Native Americans used for quite a while for many different purposes. It works great with killing EBV and other similar viruses. Since there isn't anything else out there for us to take, it's the only thing that seems to help. BUT, the raw Chaparral contains terpenes, which are bad for your liver, so you can't take Chaparral long-term without liver damage. Larrea RX is the form of Chaparral where the terpenes have been removed, and the Chaparral is concentrated. Taking Larrea long-term is not a problem.
The lone company that makes Larrea RX doesn't do a good job of keeping it in stock, so if you don't order enough, you will run out. This is exactly what happened to me. In my experience, I started taking the Larrea RX, one pill twice a day on an empty stomach, and I started to feel worse, then better, then functional again. I have CFS as my EBV symptom, so my brain is impacted the most. I tried to order more Larrea in November, but they were out of stock until the beginning of April (last week). I stretched out my supply by using 1/2 Larrea RX and half Chaparral for a month, then only Chaparral (2 pills in PM with a meal) for 2 months (I took my chances with my liver, so far no problems). I could feel my health sliding downhill slowly. I was sleeping all the time, unable to focus, unable to wake up in the morning, falling asleep in the afternoon at my desk, etc.
I started taking the Larrea RX last week when it finally came in, using 1 pill twice a day like before. Then this week I switched to 2 pills in AM and 1 pill in PM. I may increase that to 2 pills, twice a day. My exhaustion continued to slide downhill until just today. I think maybe my health has finally turned the corner. I hope so anyway, since I was able to pull myself out of bed easier than the past 3 weeks. But, I am still sleeping 9-10 hours per night and still feeling exhausted during the day, just not as much as before. We'll see if the increased dose of Larrea will help more, and I will probably start the new dose next week.
That has been my experience with the stuff. I'm happy to answer any questions that I didn't answer here, so please feel free to ask. Good luck everyone.