Post-COVID ME/CFS

The goal of this clinical trial is to test if a Lingzhi supplement (CP003) helps people with chronic fatigue or post-COVID fatigue feel better. It will also check if the supplement is safe to use. The main questions it aims to answer are: Does the Lingzhi supplement reduce fatigue symptoms? Is it safe to take? How does it affect the body's immune system and inflammation? The investigators will compare people taking the Lingzhi supplement to those who do not receive any treatment (waitlist group) to see if it works. Participants will: * Take 5 capsules once daily for 6 weeks (or wait to start treatment if in waitlist group) * Visit the clinic 2 times for blood tests (before and after taking the supplement) * Complete questionnaires 3 times about their fatigue and quality of life (4 times participants in the waitlist group)