Turkey Tail

What is turkey tail?

Turkey tail is a common woody bracket fungus named for its fan of striped, multicolored bands. It is too tough to eat as food, so it is used as a tea or extract. Two purified protein-bound polysaccharide extracts, PSK (polysaccharide-K) and PSP, have been studied most. The National Cancer Institute notes that PSK has been used as an adjunct to cancer treatment in Japan for decades (NCI PDQ).

What the research says

Cancer care

A 2022 Cochrane review of seven randomized trials with 1,569 people with colorectal cancer looked at turkey tail extract added to chemotherapy. The authors were uncertain whether it reduced side effects such as nausea, diarrhea or fatigue (very low-certainty evidence) and found low-certainty evidence of a small improvement in five-year survival. Almost all trials were done in Japan with PSK (Pilkington et al., 2022). This is the strongest body of research for any of the mushrooms in this category, yet it applies to a specific purified extract in people with cancer.

Antioxidants and general wellness

Turkey tail contains phenolic compounds with antioxidant activity in laboratory tests. Antioxidant capacity in a test tube does not show that a supplement improves health in people, and we found no human trials of turkey tail for cholesterol, blood pressure or heart health. When a product lists turkey tail for antioxidant or heart support, it is extrapolating well beyond the research.

What the cancer research does and does not mean

The PSK trials involved people already receiving surgery and chemotherapy, used a standardized pharmaceutical-grade extract, and measured outcomes such as survival. Those results cannot be applied to healthy adults taking a few dozen milligrams of turkey tail powder in a mixed formula. The NCI summary also stresses that more rigorous trials are needed before firm conclusions can be drawn.

Safety

In the cancer trials, turkey tail extracts were generally well tolerated. Because it is studied for effects on the immune system, people on immune-suppressing drugs should be careful.

How it’s used in supplements

Turkey tail is sold as capsules, powders and teas, and it is a staple of multi-mushroom blends. Products vary in whether they use fruiting body, mycelium grown on grain, or a hot-water extract, and few state their beta-glucan content. Small amounts inside a proprietary blend are unlikely to resemble the gram-level doses of PSK used in clinical studies. Anyone being treated for cancer should discuss turkey tail with their oncology team rather than self-prescribing, and people who are pregnant or breastfeeding should avoid it given the lack of safety data.