Immune support

Tolypocladium

Tolypocladium inflatum

Ciclosporin is a prescription immunosuppressant used with other medicines to prevent rejection of kidney, liver and heart transplants. It binds cyclophilin, and the complex blocks calcineurin and so the T-cell signals (NF-AT, interleukin-2) that drive rejection.

African potato

Hypoxis hemerocallidea

Used mainly as an immune stimulant, including by people with HIV. In the mid-1990s Albrecht gave a methanolic extract to HIV patients for two years and reported stable CD4 counts and falling p24 antigen, but without a control group. A 2020 systematic review found the mechanisms unknown and the claims unsubstantiated.

Astragalus

Astragalus mongholicus

A 2023 review of 19 human studies (1,094 participants) found raised immune-response markers and lower pro-inflammatory cytokines, but the studies were small and varied. The WHO monograph lists 'uses supported by clinical data' as none; immune effects rest mainly on lab and animal work with the root polysaccharides.

Balloon flower

Platycodon grandiflorus

In an 8-week Korean double-blind trial in 100 healthy adults, a 'red' balloon-flower root extract (1.5 g a day) raised natural-killer-cell activity and interferon-gamma compared with placebo, with no serious adverse events. Whether this changes infection rates was not tested.

Lingzhi (reishi)

Ganoderma lingzhi

The same review found small rises in CD3, CD4 and CD8 lymphocyte percentages (2–4 percentage points) in cancer patients; the clinical meaning is uncertain.

Longan

Dimocarpus longan

Polysaccharides from the fruit pulp enhanced immune responses (delayed-type hypersensitivity, macrophage activity) in mice and cell studies; no human trials.

Maitake (hen-of-the-woods)

Grifola frondosa

Laboratory and early clinical work only; there were no completed phase III studies as of 2019.

Prince ginseng

Pseudostellaria heterophylla

Root powder and polysaccharides raised immune markers (IL-2, interferon-γ, NK-cell activity, lymphocyte proliferation) in mice and altered gut bacteria. There are no clinical studies.

Sanghuang

Sanghuangporus sanghuang

In a randomised, placebo-controlled trial in 98 Korean adults, 1000 mg a day of a fermented Phellinus linteus mycelium extract for 8 weeks raised natural-killer-cell activity, but did not significantly change the secondary immune markers (cytokines, antibodies). Whether better lab numbers mean fewer infections was not tested.

Shiitake

Lentinula edodes

Shiitake extracts are promoted for immune support; the evidence is laboratory work and small studies.

Sika deer

Cervus nippon

In an 8-week randomised trial in 120 healthy adults aged 40–70, an enzyme-digested red-deer (C. elaphus) velvet extract raised natural-killer-cell activity compared with placebo, an immune marker rather than a clinical outcome.

Sorghum

Sorghum bicolor

Extracts of West African sorghum leaf sheaths (sold as Jobelyn) showed anti-inflammatory and immune-modulating effects on human blood cells in the test tube and in animal models; no controlled human trials were found.

Turkey tail

Trametes versicolor

A phase 1 trial in 9 women after breast-cancer radiotherapy found up to 9 g a day of a turkey-tail preparation was well tolerated, with dose-related rises in some lymphocyte counts; clinical outcomes were not measured.

Cat's claw

Uncaria tomentosa

Indigenous Amazonian peoples have used it for centuries 'to ward off disease' (NCCIH); laboratory work shows effects of its oxindole alkaloids on immune cells, but NCCIH finds no conclusive human evidence for any use, including COVID-19.

Guduchi (Giloy)

Tinospora cordifolia

Promoted in India as an immune booster to prevent COVID-19, with no clinical evidence that it does; the campaign was followed by a wave of liver-injury cases.

Noni

Morinda citrifolia

Marketed for immune health, energy and many other conditions, but NCCIH states noni has not been shown to have beneficial effects on any health condition in human studies; laboratory antioxidant, immune and anti-tumour findings have not translated into clinical evidence.