PSK, PSP and Lentinan: Mushroom-Derived Medicines vs Supplements
PSK, PSP and lentinan are mushroom-derived compounds used as regulated medicines in parts of Asia. Here is how they differ from supplements, what trials found, and cautions.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
What each one is
| Name | Source mushroom | What it is | Where it is used as a medicine |
|---|---|---|---|
| PSK (polysaccharide-K, krestin) | Turkey tail, Trametes versicolor (L.) Lloyd[2] (older name Coriolus versicolor)[3] | A proprietary protein-bound polysaccharide; NCI says a purified hot water extract of cultivated mycelium has been used in Japan.[1] | NCI says PSK is an approved product for cancer treatment in Japan and has been used as an adjunct in thousands of patients since the mid-1970s.[1] |
| PSP (polysaccharopeptide) | Turkey tail, a different strain | NCI calls PSP a very similar substance produced in China.[1] A 2019 review says it is about 60% polysaccharide and 10 to 30% peptide.[4] | The review says PSP was approved and used clinically in Japan and China since the 1970s. We did not read an official regulator record, and NCI describes PSK as the approved Japanese product. |
| Lentinan | Shiitake, Lentinula edodes (Berk.) Pegler[5] | A beta-glucan polysaccharide extracted from shiitake. | A 2019 review says it has been approved as an adjuvant cancer drug in China and Japan since the 1980s.[6] |
Memorial Sloan Kettering adds that other turkey tail extracts such as PSP are sold as dietary supplements, that many over-the-counter products are not standardized, and that it is unclear if PSK, PSP and other extracts have comparable effects.[3]
What research shows
These findings concern cancer treatment given alongside standard care. No supplement is a cancer treatment.
| Question | What the source found | Evidence label | Form and population |
|---|---|---|---|
| PSK with chemotherapy, gastrointestinal cancers | A 2017 network meta-analysis of 23 trials (10,684 patients) found PSK increased 1- to 5-year overall survival and disease-free survival, with no increase in side effects. The authors favored PSK plus chemotherapy.[7] | Promising | PSK; gastrointestinal cancers |
| PSK in colorectal cancer, a Cochrane review | Seven trials (1,569 participants; PSK extract in all). Low-certainty evidence of a small survival benefit at five years; very low certainty on adverse events. The chemotherapy used does not reflect current practice.[8] | Mixed; low certainty | Extract; stage II to IV |
| PSK in one later rectal cancer trial | A Japanese trial in stage II rectal cancer closed early after 20% of its target. Disease-free survival was slightly worse with UFT plus PSK than with surgery alone, not significantly.[9] | No benefit shown | PSK plus UFT, small |
| Lentinan injection, gastric cancer | A 2024 meta-analysis of 31 trials (2,729 patients) found better treatment response with injected lentinan plus chemotherapy than chemotherapy alone. The authors graded evidence quality 'high' or 'moderate' and called for more trials.[10] | Promising; applies to the injection only | Injected medicine, with chemotherapy |
| Lentinan from eating shiitake | Memorial Sloan Kettering says most lentinan studies used intravenous or intramuscular injections and it is uncertain whether eating shiitake has similar effects.[11] | Insufficient evidence | Food |
| PSP | A 2019 review summarizes studies from Chinese databases and says PSP is helpful for survival and quality of life; the authors say further chemical and pharmacological studies are needed.[4] | Promising but limited | PSP, review of Chinese reports |
The PSP and 2019 lentinan reviews gather reports from Chinese databases, and their abstracts do not mention a certainty grading. We did not find a Cochrane review of lentinan or PSP in the searches we ran (Proper evidence not found).
Frequently asked questions
Is PSK the same as a turkey tail supplement?
No. PSK is a specific proprietary extract used as a medicine in Japan, while other extracts are sold as supplements, and it is unclear if they have comparable effects.[1][3]
Is lentinan the same as shiitake?
No. Lentinan is a purified polysaccharide, and most lentinan studies used injections.[11]
Does PSK work?
Reviews are mixed. A network meta-analysis favored PSK with chemotherapy, a Cochrane review found low-certainty evidence of a small survival benefit, and one rectal cancer trial found no benefit.[7][8][9]
Can I buy PSK or lentinan as a supplement?
The sources we read do not describe PSK or lentinan as supplements. They describe them as medicines in Asian countries. Ask a pharmacist.
Should I take a mushroom product during cancer treatment?
Talk to the oncology team first. NCI states the FDA has not approved medicinal mushrooms to treat cancer.[1]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety first: these are not supplements, and cancer care needs the care team
PSK, PSP and lentinan are named compounds, and in some countries they are used as prescribed medicines alongside cancer treatment. A capsule, powder or tea from the same mushroom is a different product. Results for one do not transfer to the other. The US Food and Drug Administration (FDA) has not approved medicinal mushrooms as a treatment for cancer or any other medical condition, according to the National Cancer Institute (NCI, updated 2024).[1] If you are in cancer care, tell the oncology team about every product, including mushroom products. See what to tell your care team and how interactions are classed. Do not stop or change prescribed treatment; ask the prescriber or pharmacist.
Safety and who should ask first
- Side effects: NCI says few adverse events have been reported in patients treated with PSK, and its safety record is well established in Japan.[1] The Cochrane review could not say whether adverse events were due to chemotherapy or to the extract.[8] The 2024 lentinan meta-analysis reported no serious adverse effects.[10]
- Pregnancy and breastfeeding: Memorial Sloan Kettering advises avoiding Coriolus until safety data become available.[3] For lentinan, Proper evidence not found.
- Children, liver and kidney disease, surgery: Proper evidence not found in the sources we read. Ask a clinician.
- Medicines: the sources we read give no specific interaction list for PSK or lentinan. That is not proof of safety.
- Quality: supplements are not reviewed the way medicines are, and NCI says ingredients may vary lot to lot.[1] See are mushroom supplements regulated?.
Related: turkey tail, PSK and cancer care and shiitake, lentinan and immune research. A clinician decides what is right for an individual; this page gives no amounts to take.
References
- National Cancer Institute, Medicinal Mushrooms (PDQ) health professional version, updated November 6, 2024. Read 2026-10-23.
- GBIF Secretariat, GBIF Backbone Taxonomy record for Trametes versicolor (L.) Lloyd (accepted name, family Polyporaceae). Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center, Integrative Medicine, Coriolus versicolor (About Herbs, Botanicals & Other Products). Read 2026-10-23.
- Coriolus versicolor polysaccharopeptide as an immunotherapeutic in China. Progress in molecular biology and translational science. 2019. PubMed 31030754. Read 2026-10-23.
- GBIF Secretariat, GBIF Backbone Taxonomy record for Lentinula edodes (Berk.) Pegler (accepted name, family Omphalotaceae). Read 2026-10-23.
- Mushroom polysaccharide lentinan for treating different types of cancers: A review of 12 years clinical studies in China. Progress in molecular biology and translational science. 2019. PubMed 31030752. Read 2026-10-23.
- Can polysaccharide K improve therapeutic efficacy and safety in gastrointestinal cancer? a systematic review and network meta-analysis. Oncotarget. 2017. PubMed 29179503. Read 2026-10-23.
- Coriolus (Trametes) versicolor mushroom to reduce adverse effects from chemotherapy or radiotherapy in people with colorectal cancer. The Cochrane database of systematic reviews. 2022. PubMed 36445793. Read 2026-10-23.
- Randomized phase III trial comparing surgery alone to UFT + PSK for stage II rectal cancer (JFMC38 trial). Cancer chemotherapy and pharmacology. 2018. PubMed 29094178. Read 2026-10-23.
- Systematic review and meta-analysis on the efficacy and safety of Injectable Lentinan combined with chemotherapy in the treatment of gastric cancer. Phytomedicine : international journal of phytotherapy and phytopharmacology. 2024. PubMed 38100922. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center, Integrative Medicine, Shiitake Mushroom (About Herbs, Botanicals & Other Products). Read 2026-10-23.