Hi! I have also experienced brain fog in the past. It is awful. I take the Miracle Neutralizer daily and it has really helped me overall and to bring my PH into better balance.
I haven't used Intestinew, but I do regularly take Renew Life's CleanseMore, OilSmart and FiberSmart. I have also done their CleanseSmart, ParaGone and LiverCleanse cleanses. As I have taken so many of their products, I also purchased Brenda Watson's book Renew Your Life. It is loaded with great information on liver, parasite, candida, digestion, leaky gut, etc. That woman really knows her stuff and has healed herself from many of these problems.
I have tried a great many products, some not very successfully, and Renew Life's are the ones that have consistently worked very well for MY system.