Evidence Level
Reishi is a well-researched supplement known for its immune-modulating properties. A systematic review by Jin et al. (2016) analyzed five randomized controlled trials (RCTs) involving cancer patients and found that Reishi, when combined with chemotherapy or radiotherapy, improved immune cell counts compared to treatment alone. However, the evidence for tumor regression remains inconclusive due to insufficient data. Another notable study by Cui et al. (2012) demonstrated that Reishi extract significantly improved sleep duration and reduced fatigue in patients with neurasthenia.
Recent research has expanded on Reishi's potential benefits beyond immune modulation. A systematic review by Narayanan et al. (2023) evaluated 39 clinical studies involving mushroom preparations, including Reishi, and found that they may improve survival rates, immune responses, and quality of life in cancer patients. However, the authors noted that the evidence is limited by small sample sizes and a lack of large-scale randomized trials.
In terms of product quality, concerns have been raised about the composition of Reishi supplements. Many products contain mycelium grown on grain rather than the fruiting body, which may result in lower triterpene content—a key bioactive component. To address this, dual-extraction methods (combining hot water and alcohol) are recommended to ensure a comprehensive extraction of bioactive compounds.
Overall, Reishi shows promise as an adjunct therapy for immune support and symptom management in cancer patients, though further large-scale studies are needed to confirm its efficacy and optimize its use in clinical settings.