A mushroom supplement called Agaricus bisporus strain MES01706 did not significantly improve flu vaccine responses in older adults, according to a 2026 randomized controlled trial of 85 people aged 60 and older. While the mushroom group showed a slight trend toward better antibody production, the difference was not statistically significant, and antibody levels were nearly identical between the mushroom and placebo groups.
Researchers tested whether a special mushroom powder could help older people’s immune systems respond better to flu vaccines. According to Gram Research analysis, 85 adults over 60 took either mushroom powder or a placebo for 8 weeks around their flu shot. While the mushroom supplement was safe and people took it consistently, it didn’t significantly improve how well their bodies made antibodies to fight the flu. The findings suggest that while this mushroom strain has interesting properties in lab studies, it may not translate to real-world immune benefits for older adults receiving vaccines.
Key Statistics
A 2026 randomized controlled trial of 85 adults aged 60 and older found that daily consumption of 5 grams of Agaricus bisporus mushroom powder for 8 weeks did not significantly improve antibody responses to the influenza vaccine compared to placebo (p = 0.65 for IgG concentrations).
In a double-blind study of 85 older adults published in 2026, the mushroom supplement group showed only a non-significant trend toward higher antibody responses (p = 0.09), meaning the difference could easily have occurred by chance.
Research reviewed by Gram found that despite excellent compliance and safety in a 2026 trial of 85 participants, the mushroom supplement showed no significant differences in white blood cell counts, metabolic markers, quality of life, or flu-like illness rates during the 2023-2024 flu season.
The Quick Take
- What they studied: Whether taking a mushroom powder supplement could help older adults’ immune systems respond better to their annual flu vaccine
- Who participated: 85 people aged 60 and older (42 took mushroom powder, 43 took placebo) during the 2023-2024 flu season
- Key finding: The mushroom supplement group showed a trend toward better antibody responses (p = 0.09), but this difference was not statistically significant, and IgG antibody levels were nearly identical between groups (p = 0.65)
- What it means for you: If you’re over 60, this mushroom supplement probably won’t improve your flu shot effectiveness. Focus on proven strategies like getting vaccinated on time and maintaining overall health. Talk to your doctor before starting any new supplements.
The Research Details
This was a double-blind, randomized controlled trial, which is one of the strongest types of research studies. Neither the participants nor the researchers knew who was getting the real mushroom powder versus the placebo until the study ended. This prevents bias from affecting the results.
Participants were divided into two groups: one received 5 grams of Agaricus bisporus mushroom powder daily for 8 weeks (4 weeks before and 4 weeks after their flu vaccine), while the other group received an identical-looking placebo. The researchers measured antibody levels (the immune system’s defense proteins) and checked various blood markers to see if the mushroom made a difference.
The study was well-designed with excellent compliance—participants took their capsules consistently, which the researchers confirmed by measuring ergothioneine, a compound found in mushrooms that builds up in the body with regular consumption.
This research design is important because it moves beyond lab studies to test whether the mushroom actually works in real people. The double-blind approach eliminates placebo effects and researcher bias. Testing during actual flu season with real vaccines provides practical, real-world evidence rather than artificial laboratory conditions.
Strengths: This was a well-conducted randomized controlled trial with good participant compliance and proper blinding. The sample size was reasonable for this type of study. Limitations: The study only included 85 people, which is relatively small. It only tested one specific mushroom strain at one dose level. The study lasted only 8 weeks total, which may not be long enough to see immune benefits. Results were published in 2026, so long-term effects remain unknown.
What the Results Show
The main finding was that the mushroom supplement did not significantly improve flu vaccine responses in older adults. While the mushroom group showed a slight trend toward higher antibody responses compared to placebo (p = 0.09), this difference was not statistically significant—meaning it could easily have happened by chance.
When researchers looked at IgG antibodies specifically (the main type of antibody that protects against flu), there was virtually no difference between the mushroom and placebo groups (p = 0.65). This means the two groups had nearly identical immune responses to the vaccine.
The mushroom supplement was safe and well-tolerated. Participants had no serious side effects, and compliance was excellent, with people taking their capsules consistently throughout the study. This confirms that the supplement itself wasn’t harmful, just ineffective for this purpose.
The researchers also measured white blood cell counts, metabolic markers, and quality of life measures. None of these showed significant differences between groups. Importantly, there were no differences in how many people got flu-like illness during the 2023-2024 flu season, suggesting the supplement didn’t provide any practical protection benefit either.
Previous laboratory studies and animal studies had shown that this specific mushroom strain had interesting immune-boosting properties in controlled settings. However, this human study suggests those lab findings don’t automatically translate to real-world benefits in older adults. This is a common pattern in nutrition research—what works in a test tube or in mice doesn’t always work in people.
The study had several limitations worth considering. First, only 85 people participated, which is a relatively small sample size. Second, researchers only tested one specific dose (5 grams) of one specific mushroom strain, so different amounts or strains might work differently. Third, the study only lasted 8 weeks total, which may not be long enough for immune benefits to develop. Finally, all participants were 60 or older, so results may not apply to younger people.
The Bottom Line
Based on this research, taking this mushroom supplement is unlikely to improve your flu vaccine response. Instead, focus on proven strategies: get your flu vaccine every year, maintain a healthy diet rich in fruits and vegetables, exercise regularly, get adequate sleep, and manage stress. If you’re interested in immune-supporting supplements, discuss options with your doctor. Confidence level: Moderate—this is one well-designed study, but more research with larger groups would strengthen these conclusions.
This research is most relevant to adults over 60 considering mushroom supplements to boost vaccine effectiveness. It’s also important for healthcare providers advising older patients about immune support. People with compromised immune systems should definitely consult their doctor before starting supplements. Younger adults may want to wait for research specific to their age group.
If you were already taking this mushroom supplement, you wouldn’t expect to see changes in your flu vaccine response. The study measured effects over 8 weeks, and no benefits appeared during that timeframe. If you’re considering starting it, the research suggests waiting for more evidence before investing time and money.
Frequently Asked Questions
Does mushroom powder help your immune system fight the flu?
A 2026 study of 85 older adults found that Agaricus bisporus mushroom powder did not significantly improve flu vaccine responses. While safe and well-tolerated, it showed no meaningful immune benefits compared to placebo for flu protection.
Should I take mushroom supplements before getting my flu shot?
Current research doesn’t support taking this mushroom supplement to boost flu vaccine effectiveness. Focus instead on proven strategies: get vaccinated annually, eat a healthy diet, exercise regularly, sleep well, and manage stress. Consult your doctor before starting any supplements.
What supplements actually improve flu vaccine response in older adults?
Research shows mixed results for most supplements. Vitamin D and zinc have some evidence, but results vary. The most proven approaches are vaccination itself, good nutrition, regular exercise, adequate sleep, and stress management. Talk to your healthcare provider about what’s best for you.
Why did the mushroom supplement not work if lab studies showed promise?
Lab studies and animal studies don’t always translate to human benefits. This mushroom showed immune properties in test tubes and mice, but those controlled conditions differ greatly from how the human body actually works. More research is needed to understand why.
Is the Agaricus bisporus mushroom supplement safe to take?
Yes, the 2026 study found the supplement was safe and well-tolerated with no serious side effects in older adults. However, safety doesn’t mean it’s effective. Always discuss new supplements with your doctor, especially if you take medications.
Want to Apply This Research?
- Track your annual flu vaccine date and any flu-like symptoms during the season. Note whether you took any supplements and monitor how many days you experienced illness symptoms compared to previous years.
- Rather than adding an unproven supplement, use the app to track proven immune-supporting habits: daily vegetable servings, exercise minutes, sleep hours, and stress management activities. These have stronger evidence for supporting immune health.
- Set a reminder for your annual flu vaccine. After vaccination, log any mild symptoms (arm soreness, low fever) and track illness during flu season. Compare your health outcomes year-to-year to see what habits correlate with staying healthy, rather than relying on supplements without proven benefits.
This research summary is for educational purposes only and should not replace professional medical advice. The study found that this mushroom supplement did not improve flu vaccine responses in older adults. Before starting any new supplement, especially if you’re over 60, have a compromised immune system, take medications, or have health conditions, consult with your healthcare provider. This article discusses one study; individual results may vary, and more research may change current understanding. Always get your annual flu vaccine as recommended by health authorities, regardless of supplement use.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.