A 60-day trial of quercetin in 52 adults with ASD showed within-group improvements in social responsiveness scores and physical quality of life, but between-group differences versus placebo were not statistically significant. Evidence is preliminary; larger trials are needed before drawing clinical conclusions.
Researchers conducted a randomized, triple-blind, placebo-controlled trial examining whether quercetin, a polyphenolic compound found in plants, could improve symptoms and quality of life in adults with autism spectrum disorder. The trial enrolled 52 adults with confirmed ASD diagnoses, randomly assigning them to receive either quercetin or placebo for 60 days. This design represents a rigorous approach to assessing a supplement's effects, as the triple-blind structure (participants, researchers, and analysts all masked to group assignment) reduces bias.
The primary outcome was the Social Responsiveness Scale (SRS), a validated 65-item measure of social impairment across five domains. The quercetin group showed a statistically significant reduction in SRS scores over the 60-day period (p = 0.010), interpreted as improvement in social responsiveness. The placebo group showed no significant within-group change (p = 0.655). However, this distinction is important: within-group changes do not necessarily indicate that quercetin caused the improvement. When the researchers directly compared how much each group improved relative to the other (the between-group analysis), the difference was not statistically significant. This pattern often emerges when both groups improve somewhat, but one group shows more improvement that happens to reach statistical significance by chance or other factors.
Secondary outcomes measured quality of life using the WHO Quality of Life (WHOQOL) instrument, which assesses physical health, psychological well-being, social relationships, and environmental domains. At week 8, the quercetin group showed greater improvement in the physical health domain at the unadjusted statistical level (p = 0.044), but this advantage disappeared after adjustment for multiple comparisons (p = 0.082). The environmental health domain showed a borderline difference favoring quercetin (adjusted p = 0.053), which also falls short of conventional statistical significance. No serious adverse events were reported in either group, suggesting quercetin was well-tolerated at the dose and duration tested.
The trial's key limitation is that between-group differences in the primary outcome (SRS change) were not significant. When interpreting RCTs, the between-group comparison is the gold standard for establishing whether a treatment works, because it controls for placebo effects, natural symptom fluctuation, and regression to the mean. Within-group improvements can occur for many reasons unrelated to the intervention itself. The authors acknowledge this constraint, stating that "larger, well-designed trials are needed to confirm its clinical effectiveness."
This study identifies a potential signal worth further investigation, but does not establish that quercetin improves ASD symptoms in adults. If you or someone you know has ASD, this trial alone does not provide sufficient evidence to justify starting quercetin supplementation specifically for social or behavioral symptoms. The between-group analysis, which is the appropriate test of efficacy, did not reach significance.
The broader context matters here: quercetin is a flavonoid present in many foods (onions, apples, tea, berries) and has been studied for various conditions, though evidence of clinical benefit remains mixed for most indications. If you are considering any supplement for ASD-related concerns, consulting with a healthcare provider familiar with your specific presentation is essential. ASD presents heterogeneously, and interventions that might help one person may not help another.
The study provides reassurance about safety at the dose tested (60 days of supplementation produced no serious adverse events), but safety in a short trial does not necessarily predict safety with long-term use. The 52-person sample is modest for detecting true treatment effects; larger, adequately powered trials would be needed to either confirm or refute quercetin's utility.
| Parameter | Details |
|---|---|
| Study Type | Randomized, triple-blind, placebo-controlled trial |
| Sample Size | 52 adults with ASD |
| Intervention | Quercetin supplementation for 60 days |
| Control | Placebo for 60 days |
| Primary Outcome | Social Responsiveness Scale (SRS) scores |
| Secondary Outcomes | WHO Quality of Life domains (physical health, psychological, social, environmental) |
| Key Finding (Primary) | Within-group SRS improvement in quercetin group (p = 0.010); between-group difference not significant |
| Key Finding (Secondary) | Physical health domain favored quercetin at unadjusted level (p = 0.044), not significant after adjustment (p = 0.082); environmental domain borderline (adjusted p = 0.053) |
| Safety | No serious adverse events reported |
| Journal | Human Psychopharmacology |
| Registration | IRCT20241214064050N1 |
Quercetin and Autism Spectrum Disorder - PubMed: https://pubmed.ncbi.nlm.nih.gov/42438230/
ProtocolEngine provides general health information based on published research. This is not medical advice. Consult a healthcare professional before starting any supplement or health protocol.