Wachtel-Galor S., Tomlinson B., Benzie I.F.F. Ganoderma lucidum ('Lingzhi'), a Chinese medicinal mushroom: biomarker responses in a controlled human supplementation study. Br J Nutr. 2004;91(2):263–269.
Rationale
The group's acute study showed antioxidant absorption; the obvious next question — does daily intake change anything durable? This 4-week crossover asked it directly.
Methods
A double-blind placebo-controlled crossover: 18 healthy adults took 1.44 g/day of a commercial encapsulated reishi preparation (≈13.2 g fresh-mushroom equivalent) or placebo for 4 weeks per phase, measuring antioxidant status, lipids, DNA damage, immune and inflammatory markers.
Results
No biomarker — antioxidant status, lipids, DNA damage, immunity, inflammation — changed significantly versus placebo. Tolerability was clean throughout.
Conclusions
Four weeks of reishi at this dose changed nothing measurable — an honest null that directly contradicts the acute absorption signal's implied promise.
Worth noting
This is the kind of negative replication the supplement literature needs and rarely publishes. The contrast is instructive: acute antioxidant capacity demonstrably rises after a dose; nothing persists or accumulates over a month. The later 6-month enriched-preparation RCT found the positive this study missed — dose enrichment and duration are the candidate explanations.