Evidence Level
Moderate
Reishi has moderate clinical evidence primarily for immune modulation. The most rigorous evidence comes from Jin et al. (2016) Cochrane review, which analyzed 5 RCTs of reishi in cancer patients and found improved immune cell counts but insufficient evidence for tumor regression. Cui et al. (2012) published a notable RCT showing sleep and fatigue improvements in neurasthenia patients. A key quality concern: many reishi supplements contain mycelium grown on grain rather than fruiting body, which may have lower triterpene content. Dual-extraction (hot water + alcohol) products are considered superior for capturing the full spectrum of bioactive compounds.