Benefits
Viral test results over 6 months in a placebo-controlled trial
In a double-blind trial in 50 women over 30 with high-risk HPV lasting over 2 years (41 completed), 14 of 22 on AHCC 3 g a day tested negative after 6 months. Placebo was reported only at 12 months (2 of 19 negative), with no between-group test, so the trial does not show an effect. NIH funded it, and the maker gave product and placebo.
Dendritic cell counts and function, immune markers
In a double-blind trial in 21 healthy volunteers, 3 g a day for 4 weeks raised the number of circulating dendritic cells (immune cells that present antigens) and a lab test of their function compared with placebo. Natural killer cell activity and T-cell responses did not differ between groups. These are marker changes, not a health outcome.
Vaccine antibody response and immune cell markers in healthy adults
In 30 healthy adults, 3 g a day for 3 weeks after a flu shot raised CD8 T cells versus controls, while the rise in influenza B antibody titers was significant within the AHCC group only. In 34 healthy adults, 1 g a day for 4 weeks in early winter kept natural killer cell numbers steady while they fell on placebo; maker staff ran that trial. Both are marker results.
Inflammatory cytokines and liver enzymes over 12 weeks
In a double-blind trial in 69 adults with fatty liver and raised liver enzymes linked to heavy drinking (62 completed), percentage changes in TNF-alpha and IL-1 beta were lower, and adiponectin higher, on 1 or 3 g a day than placebo over 12 weeks. IL-1 beta was higher in the AHCC groups at baseline. Of the liver enzymes, only the ALT change differed. The maker funded it.
T-cell interferon-gamma markers in adults over 50
In healthy adults aged 50 or older, the share of CD4 and CD8 T cells making interferon-gamma or TNF-alpha rose during AHCC intake compared with each person's baseline and stayed higher 30 days after stopping. There was no placebo group, so the change cannot be separated from time or season.
Mechanism of action
An alpha-glucan rich mushroom mycelia extract
A 2025 analysis of three AHCC lots measured alpha-glucan at about 26% of dry matter and quantified two isomaltol sugar compounds. The HPV trial authors describe AHCC as mainly alpha-glucan, in contrast with most mushroom extracts, which are made up of beta-glucans.
Dendritic cell and T-cell markers in human trials
In healthy volunteers, AHCC raised dendritic cell numbers versus placebo in one trial, and T cells making interferon-gamma rose versus baseline in an uncontrolled study. In a 40-man trial, AHCC alone did not change T-cell cytokine output versus placebo, and a dendritic cell shift was seen only with a probiotic combination. These trials did not measure health outcomes.
Natural killer cells: human results differ
NK cell activity did not differ from placebo at 3 g a day for 4 weeks, rose in both groups in a 1 g a day winter trial, and changed by less than 10% (not significant) in the HPV trial. These trials do not support the common claim that AHCC raises NK activity in people.
Interferon-beta in the viral infection trial
In the HPV trial, women on AHCC whose interferon-beta fell below 20 pg/ml were the ones whose results stayed negative, alongside rises in T lymphocytes and interferon-gamma. This is a correlation within the AHCC group, not a tested mechanism.
Clinical trials
Randomized, double-blind, placebo-controlled phase 2 trial (NCT02405533); AHCC 3 g once daily on an empty stomach for 6 months then placebo for 6 months, versus placebo for 12 months; primary outcome clearance confirmed by both HPV RNA and HPV DNA tests; funded by an NIH-NCI small grant; Amino Up supplied AHCC and matching placebo; the lead author received unrestricted Amino Up grants for preclinical AHCC work before 2014 (Smith et al. 2022, Front Oncol)
50 women over 30 with high-risk HPV infection confirmed for more than 2 years; 41 completed (22 AHCC, 19 placebo).
14 of 22 (63.6%) on AHCC were negative on both HPV RNA and DNA tests after 6 months, and 9 of 22 (40.9%) stayed negative after stopping (the paper gives that interval as 6 months in its definition and 12 months in its results text). On placebo, 2 of 19 (10.5%) were negative at 12 months. No placebo count is given at 6 months, and no between-group statistical test of clearance is reported (the methods name a Mann-Whitney test, but no result is given, and ClinicalTrials.gov lists no posted results). Of 12 placebo patients who then took AHCC unblinded, 6 were negative after 6 months. No adverse event above grade 1 occurred in either arm.
Randomized, double-blind, placebo-controlled trial; 3 g/day for 4 weeks; Kansai Medical University, Japan; the abstract does not state funding (Terakawa et al. 2008, Nutr Cancer)
21 healthy volunteers (10 AHCC, 11 placebo).
Total dendritic cells rose versus baseline and versus placebo, and an allogeneic lymphocyte reaction (a test of dendritic cell function) rose versus placebo. Natural killer cell activity, T-cell proliferation and stimulated signaling protein output did not differ between groups. Immune-marker results only.
Randomized, placebo-controlled trial; 1 g/day for 4 weeks in early winter; all authors are Amino Up Chemical staff, and the abstract gives no between-group statistics (Takanari et al. 2015, J Evid Based Complementary Altern Med)
34 healthy adults.
NK cell activity rose in both groups. NK cell numbers did not change on AHCC but fell markedly on placebo, and an immunological vigor score (an index of overall immune competence) held steady on AHCC but fell on placebo. Marker results from a maker-run study.
Randomized controlled trial; AHCC 3 g/day started right after the 2009 to 2010 seasonal flu vaccine, with blood drawn before and 3 weeks after vaccination; Michigan State University; the abstract does not describe a placebo or state funding (Roman et al. 2013, Nutr Res)
30 healthy adults.
CD8 T cells rose versus controls (P < .05) and NKT cells showed a trend (P < .1). Protective antibody titers to influenza B improved significantly within the AHCC group but not within the control group, a within-group comparison. Marker results only.
Randomized, double-blind, placebo-controlled trial at Chung-Ang University, Seoul, in 2010; 1 g or 3 g/day in capsules for 12 weeks; primary outcomes AST, ALT and GGT; baseline IL-1 beta differed among groups (p = 0.02, higher in the AHCC groups); between-group tests were three-group ANOVA or Kruskal-Wallis; the sponsor generated the randomization sequence; Amino Up Chemical supplied the capsules and financially supported the study; the authors declared no conflict of interest (Kim et al. 2014, J Nutr Sci Vitaminol (Tokyo))
69 adults aged 18 to 75 with fatty liver on ultrasound, raised liver enzymes and regular heavy alcohol intake; 62 completed.
Liver enzyme levels at 12 weeks did not differ between groups, but the percentage change in ALT did (p = 0.04); AST and GGT changes did not. Percentage changes in TNF-alpha (p < 0.05) and IL-1 beta (p < 0.01) were lower, and adiponectin higher (p < 0.05), in the AHCC groups than placebo. At 12 weeks, IL-1 beta and adiponectin levels differed among groups but TNF-alpha levels did not (p = 0.12). Fatigue and stress questionnaire scores did not differ. No adverse events were reported on AHCC.
Phase I multiple-dose safety study with no control group described; 9 g/day of liquid AHCC (150 mL) by mouth for 14 days; laboratory tests at baseline and day 14 (Spierings et al. 2007, J Nutr Sci Vitaminol (Tokyo))
26 healthy men and women aged 18 to 61.
2 (7%) dropped out because of nausea and intolerance of the liquid. Nausea, diarrhea, bloating, headache, fatigue and foot cramps occurred in 6 (20%), described as mild and transient. No laboratory abnormalities were found.
Non-randomized prospective cohort from 1992 to 2001 at Kansai Medical University; patients were not randomized to AHCC and there was no placebo; results from Cox multivariate analysis (Matsui et al. 2002, J Hepatol)
269 consecutive adults after surgery for hepatocellular carcinoma, 113 of whom took AHCC by mouth.
AHCC users had a longer recurrence-free period (HR 0.639, 95% CI 0.429 to 0.952) and longer overall survival (HR 0.421, 95% CI 0.253 to 0.701) than non-users. Because treatment was not randomized, this cannot show that AHCC caused the difference. Context only, not evidence that AHCC treats cancer.