Updated
Button mushroom
The mushroom nearly everyone has actually eaten, and about a third of all mushrooms grown in the world. White, cremini and portobello are one species at three ages. Left under ultraviolet light its ergosterol turns into vitamin D, which is the one thing about it that has been tested in people repeatedly.
A first trial

Where it stands: 6 registered trials in people, none of which has reported a result; 15 randomised trials published since 1999.
What it is taken for
One tile per use. The line under each is how far the evidence for that use actually got, counted rather than argued.
What it has been tried for, and how far that has got
One row per use. The label is counted rather than argued — it is set by how many randomised trials and posted results exist for that use, and nothing else. How that is worked out.
| Use | How far it has got | Trials | With a result | Randomised, published | Reviews | Commonly taken for it |
|---|---|---|---|---|---|---|
| Viral infection | A first trial | 1 | 0 | 1 | 0 | — |
| Inflammation | A first trial | 1 | 0 | 1 | 0 | — |
| Nutrition | A first trial | 1 | 0 | 1 | 0 | yes |
| Cholesterol and lipids | A first trial | 0 | 0 | 1 | 0 | yes |
| Skin | A first trial | 0 | 0 | 1 | 0 | — |
| Cancer, supportive and adjuvant | Being tested now | 4 | 0 | 0 | 0 | — |
| Blood sugar | Laboratory work | 0 | 0 | 0 | 0 | yes |
| Immune function | Laboratory work | 0 | 0 | 0 | 0 | yes |
Commonly taken for immune function, blood sugar. The work there is still laboratory and animal work — often a great deal of it — and the step into a trial in people has not been taken yet.
The doses the protocols actually specify
Taken verbatim from the intervention description each trial filed. These are not recommendations and they are not comparable to each other: some are a whole-mushroom powder, some a purified fraction.
Every registered study that names it
From ClinicalTrials.gov, filtered to studies that name Agaricus bisporus or a synonym in the title, summary or intervention. Studies that have posted results come first.
| Register | Study | Condition | People | Status | Result posted | Dose in the protocol |
|---|---|---|---|---|---|---|
| NCT04519879 | White Button Mushroom Sup for the Reduction of PSA in Pts With Biochemically Rec or Therapy Naive Fav Risk Pro | Prostate Adenocarcinoma, PSA Failure | 133 | Suspended | — | — |
| NCT06041867 | Agaricus Bisporus and Influenza Vaccination Response | Immune Response | 88 | Completed | — | 10 capsule, 500 mg |
| NCT04913064 | Effects of White Button Mushroom on Inflammation in Obese Postmenopausal Women at High Risk of Breast Cancer | Breast Carcinoma | 26 | Recruiting | — | — |
| NCT00709020 | White Button Mushroom Extract in Preventing the Recurrence of Breast Cancer in Postmenopausal Breast Cancer Su | Breast Cancer, Cancer Survivor | 16 | Completed | — | 5 g/day, 8 g/day |
| NCT05214807 | Long-term Safety and Performance of KiOmedine CM-Chitosan Supplementation in Advanced Symptomatic Knee Osteoar one ingredient in a multi-herb preparation | Osteoarthritis, Knee | 104 | Unknown | — | 8.0 mg, 2.0 mg |
| NCT00779168 | White Button Mushroom Extract in Treating Patients With Recurrent Prostate Cancer After Local Therapy | Prostate Cancer | 36 | Completed | — | 4 g, 6 g |
| NCT01825616 | Vitamin D2, Muscle Damage, NASCAR Pitcrew | Muscle Function, Muscle Soreness | 33 | Completed | — | — |
The compounds the research names
Formula and mass from PubChem. Naming a compound is not a claim that it does anything in a person.
C9H15N3O2S
C28H44O
C28H44O
In the kitchen
Mild and familiar raw; properly savoury once browned. Cremini and portobello are the same species left to grow on and darken.
The one mushroom most people have actually cooked. Browned hard in a dry pan before any fat goes in, it is a different ingredient from the watery sliced version.
Where it has been recorded, and when it fruits
2,816 verified occurrence records with coordinates, from GBIF. This is where people have recorded it, which follows where recorders live as much as where the fungus grows — read the shape, not the ranking.
| United Kingdom | 581 | |
| United States | 497 | |
| Finland | 249 | |
| MA | 204 | |
| France | 151 | |
| Sweden | 146 | |
| Netherlands | 125 | |
| Spain | 108 | |
| Denmark | 96 | |
| Austria | 83 | |
| Ukraine | 69 | |
| Estonia | 66 |
Most records fall in Sep. Northern-hemisphere recorders dominate the dataset, so a southern population would not show here.
iNaturalist separately holds 173 research-grade observations of it.
What has been reported going wrong
No voluntary adverse-event report to the US Food and Drug Administration names a product by this name. That is an absence of reports, not a demonstration of safety: these are the products least likely to be reported on, because nobody is required to.
The newest randomised trials and reviews
Indexed in Europe PMC. Titles and journals only — follow the link to read the paper where the publisher allows it.

