Positives

• Roughly 4 in 10 Long COVID patients who tried reishi rate it helpful, and one patient reported a slight increase in energy after roughly 2 months of reishi extract powder Phoenix Rising.
• Patients on reishi commonly describe better sleep quality and reduced cortisol-adjacent symptoms after 3-4 weeks, with WebMD citing stress and mood benefit in patient surveys WebMD.

Negatives

• Multiple WebMD reviewers reported stomach pain severe enough to discontinue, plus dizziness, dry mouth and rash; one patient described the stomach effects as “so terribly bad” they stopped within days WebMD.
• One patient took cordyceps and reishi regularly and noticed neither benefit nor harm, and several others reported a paradoxical stimulant effect that interfered with sleep at evening doses Phoenix Rising.

Hurdles & Side Effects

• Reishi has anticoagulant activity and should be paused before surgery and used cautiously alongside warfarin, apixaban, or aspirin — relevant for the Long COVID patients on anticoagulation for microclot management Rupa Health.
  
  
• Effective doses (1-3 g/day of standardized hot-water extract, or 1500-3000 mg of dual-extracted powder) require expensive, well-sourced products; cheaper mycelium-on-grain products contain mostly starch with minimal active triterpenes Longevity Botanicals.