There can be many underlying reasons for chornic fatigue syndrome but the gut is a fundamental place to start. Not only is a healthy gut the foundation of a good immune system but if nutrient absorption is not optimum from there, the body would find it hard to correct any deficiencies.
If you have a history of digestive issues I would recommend some repair by taking microbz Revive first, for 1 or 2 months depending on how it is, and then moving onto microbz Sustain for regular maintenance. If there are no digestive issues then you could start with microbz Sustain.