Melatonin dominates the natural sleep aid market. Americans spent more than $1.8 billion on it in 2024, and it is the supplement most likely to be recommended by pharmacists for occasional sleeplessness. But a late-breaking abstract presented at the SLEEP 2026 Annual Meeting in Baltimore suggests that a far less mainstream option — reishi mushroom extract — may be substantially more effective for chronic insomnia.
In an 8-week randomized, parallel-group trial of 218 adults with chronic insomnia, participants receiving reishi mushroom extract showed a mean reduction of 8.7 points on the Insomnia Severity Index (ISI), compared with 5.6 points for those taking melatonin. The between-group difference of 3.1 points was statistically significant and clinically meaningful — the accepted threshold for a meaningful change on the ISI is 6 points, and the reishi group cleared it while the melatonin group did not.
Study Design
The trial randomly assigned 218 adults with chronic insomnia — defined as difficulty sleeping at least three nights per week for three or more months — to receive either melatonin 5 mg nightly or reishi mushroom extract 980 mg nightly, standardized to 6% triterpenes.
The primary outcome was the change in ISI score from baseline to week 8. The ISI is a validated 7-item self-report measure scored from 0 to 28, with higher scores indicating more severe insomnia. A score of 15 or above corresponds to moderate-to-severe clinical insomnia.
Of 218 randomized participants, 209 completed the study — a retention rate of 95.9%. No serious adverse events were reported in either group during the trial period.
Why Reishi Might Work
Reishi (Ganoderma lucidum) has been used in traditional Chinese and Japanese medicine for centuries, primarily as an adaptogen and immune modulator. Its potential as a sleep aid is attributed to bioactive triterpenes — specifically ganoderic acids — that appear to modulate GABAergic neurotransmission.
GABA is the brain's primary inhibitory neurotransmitter. Reduced GABAergic tone is a hallmark of the hyperarousal state that characterizes chronic insomnia. Benzodiazepines and the "Z-drugs" (zolpidem, eszopiclone) work by enhancing GABA receptor activity. If reishi triterpenes modulate the same system through a gentler mechanism, that would explain both the sleep benefits and the favorable safety profile observed in the trial.
This mechanism is distinct from melatonin's. Melatonin signals the suprachiasmatic nucleus that it is time to sleep — essentially adjusting the circadian clock — but does not directly reduce the cortical hyperarousal that keeps people with chronic insomnia awake. That mismatch may explain why melatonin performs modestly in chronic insomnia trials despite being effective for circadian rhythm disorders and jet lag.
Limitations and Open Questions
The trial, while well-designed, has important limitations. Eight weeks is relatively short for a chronic insomnia intervention; the durability of the reishi benefit beyond the treatment period is unknown. The study did not include a placebo arm, so both groups' improvements include placebo effects — the relevant finding is the between-group difference, not the absolute change in either arm.
Supplement standardization is also a concern. The trial used reishi extract standardized to 6% triterpenes, but commercially available reishi products vary widely in triterpene content and may use different extraction methods. Consumers cannot assume that any reishi supplement will reproduce the trial results.
Additionally, this is a single trial. Replicating the findings in a larger, multi-center study with a placebo arm and longer follow-up is essential before reishi can be recommended as a first-line treatment for chronic insomnia.
Context Within the Supplement Landscape
The trial arrives at a moment of growing scrutiny around melatonin. A 2022 study in JAMA found that some melatonin supplements contained up to 347% of the labeled dose, and the American Academy of Sleep Medicine issued a health advisory about melatonin use in children. Meanwhile, the U.S. supplement market has expanded to include dozens of "sleep stacks" combining melatonin with magnesium, L-theanine, ashwagandha, and other ingredients — none of which have been tested head-to-head against each other in rigorous trials.
The SLEEP 2026 reishi trial is notable precisely because such head-to-head comparisons are rare in the supplement space. Most natural sleep aids are tested only against placebo, making it impossible for consumers or clinicians to compare options.
What This Means for Patients
If you have chronic insomnia, the most effective treatment remains cognitive behavioral therapy for insomnia (CBT-I), which every major sleep medicine society recommends as first-line. Supplements — whether melatonin, reishi, or anything else — are not substitutes for addressing the behavioral and cognitive patterns that perpetuate insomnia.
That said, this trial suggests that reishi mushroom extract deserves serious investigation as a natural sleep aid. If you are considering trying it, look for products standardized to triterpene content and discuss the option with your doctor, particularly if you take blood thinners or immunosuppressive medications, as reishi may interact with both.
The broader lesson is that melatonin's dominance of the natural sleep aid market may reflect marketing momentum more than clinical evidence — and that the field is overdue for rigorous comparisons among the alternatives.
