Condition
Autism Spectrum Disorder (ASD)
Can supplements help autism? No supplement has been shown to change autism's core features, the differences in social communication and the repetitive behaviors or focused interests. A 2022 review of drug and supplement trials, 125 of them in 7,450 children and teens, found only imprecise hints for omega-3s, folinic acid, probiotics and sulforaphane, with low or very low confidence. Vitamin D results are mixed. Melatonin has the clearest benefit, for sleep: in 5 trials, autistic children and teens slept about 44 minutes longer than on placebo. Behavioral therapies come first, and some medicines ease irritability. Ask the child's clinician before any supplement, because melatonin labels are often inaccurate.
Sources: PMID 35246237; PMID 32893747; PMID 37119216; PMID 32112261; PMID 36625807; PMID 27855744
- Supplements studied
- 8
- Graded outcomes
- 5
- Trials
- 9
- People studied
- 1,925
What the evidence says
- No supplement has been shown to change core autism features. A 2022 network review pooled trials of 41 medicines and 17 supplements: 125 trials with 7,450 children and teens, and 18 with 1,104 adults. Folinic acid, omega-3s, probiotics and sulforaphane showed some hints of benefit, but the estimates were imprecise and not robust, and confidence was low or very low. Most trials had 20 to 80 people and lasted 8 to 13 weeks.
- Omega-3s and vitamin D: mixed results. A 2017 review of 5 trials with 183 children found mostly no difference from placebo, and parents rated some behaviors worse on omega-3s. A 2026 review of 12 trials found small gains in irritability and speech, which its authors called clinically modest. For vitamin D, one review (5 trials, 349 children) found a small drop in hyperactivity but no change in core features, and another (8 trials, 266 children) found less stereotyped behavior and no other differences.
- Sulforaphane, from broccoli sprouts, looked promising first and less so later. In an 18-week trial in young men aged 13 to 27 (29 on sulforaphane, 15 on placebo), behavior scores improved 34% and social scores 17%, against under 3.3% change on placebo, and scores drifted back after stopping. In 57 children aged 3 to 12, there was no significant difference on the main measure, though caregiver behavior ratings improved. In 40 children aged 3 to 7 there was no significant difference from placebo, and in 108 children, clinician ratings improved but caregiver ratings did not.
- Folinic acid (leucovorin, a form of folate, vitamin B9): small trials only. In 48 children with autism and language impairment, 12 weeks of folinic acid improved verbal communication more than placebo, most clearly in children with folate receptor autoantibodies. A pilot trial in 19 children also reported gains on an autism rating. A 2024 trial of folinic acid in children was retracted in 2026, and a 2026 review says larger confirmatory studies are needed.
- Probiotics and N-acetylcysteine (NAC): weak evidence. One review of 12 trials with 630 young people under 20 found a borderline benefit of probiotics on core features, but 9 trials had a high risk of bias and the authors found no high-quality support; another review of 8 trials with 318 people found better behavior scores. For NAC, 5 trials of 8 to 12 weeks found less irritability and hyperactivity in children, and the authors asked for more evidence before any general recommendation. Our database grades NAC and sulforaphane B; later sulforaphane trials in children were weaker than the first.
- Melatonin for sleep has the clearest benefit. Sleep difficulties affect 13% of autistic people against 5% of others. In a 13-week trial of 125 children and teens whose sleep had not improved with behavioral steps alone, those on prolonged-release melatonin slept 57.5 minutes longer a night on average, against 9.14 minutes on placebo, and fell asleep faster; sleepiness was more common with melatonin. A review of 5 trials found 44 minutes more sleep and 39 minutes faster sleep onset than placebo.
Safety and when to see a clinician
- Talk to the child's clinician before starting any supplement, and bring a list of everything the child already takes, including prescribed medicines. Behavioral interventions are the first-line therapy, and risperidone or aripiprazole, prescribed by a clinician, can ease irritability and aggression; their most common side effects are changes in appetite, weight and sleep.
- Melatonin products vary. In a lab test of 31 melatonin supplements, the melatonin content ranged from 83% below to 478% above the label, and 8 contained serotonin. Ask the child's clinician which product and amount to use, and try a steady bedtime routine first.
- Autistic people have higher rates of depression, anxiety and sleep problems, and of epilepsy when they also have an intellectual disability. See a clinician promptly for seizures, loss of words or skills the child had gained, or a sudden change in sleep, eating or behavior that could signal pain or illness.
- If an autistic teen or adult talks about suicide or self-harm, call or text 988 in the US, or your local emergency number.
Evidence by supplement
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 56 people | |||
| Irritability | Improves (the measure goes down) | 2 studies | 56 people | |||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Behavioral Symptoms (ABC) 34% improvement in Aberrant Behavior Checklist scores | Improves (the measure goes down) | Moderate effect | 150 people | |||
| Social Responsiveness (SRS) 17% improvement in Social Responsiveness Scale | Improves (the measure goes up) | Small effect | 120 people | |||
| Cognitive Function Small Improvement in cognitive measures | Improves (the measure goes up) | Small effect | 90 people |
Coenzyme Q10
- Anti-Oxidant Enzyme Profile: improves
- Oxidative Stress Biomarkers: improves
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anti-Oxidant Enzyme Profile Small Increase | Improves (the measure goes up) | Small effect | 2 studies | 78 people | ||
Studies that measured anti-oxidant enzyme profile | ||||||
| Oxidative Stress Biomarkers | Improves (the measure goes down) | 9 studies | 78 people | |||
Studies that measured oxidative stress biomarkers
| ||||||
| Autism Symptoms | Improves (the measure goes down) | 78 people | ||||
Probiotics
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms | Improves (the measure goes down) | 3 studies | 480 people | |||
Studies that measured autism symptoms
| ||||||
Ginkgo Biloba
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms | Improves (the measure goes down) | 2 studies | 50 people | |||
Fish Oil
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms | Improves (the measure goes down) | 1 study | 54 people | |||
Studies that measured autism symptoms | ||||||
L-Carnitine
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms | Improves (the measure goes down) | 1 study | 30 people | |||
Studies that measured autism symptoms | ||||||
Inositol
- Autism Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Autism Symptoms | Improves (the measure goes down) | 1 study | 9 people | |||
Studies that measured autism symptoms | ||||||
Key findings
- Autism SymptomsImproves (the measure goes down)
- Behavioral Symptoms (ABC)Improves (the measure goes down)
- Social Responsiveness (SRS)Improves (the measure goes up)
The Autism Spectrum Disorder (ASD) Nutritional Support protocol
2 primary supplements · 6 supporting supplements
- Omega-3 Fatty Acids500–1,000 mg EPA+DHA daily for children (weight-based)
- ProbioticsMulti-strain formula, 5–10 billion CFU daily
Studies cited
20 studies from PubMed
- Pharmacological and dietary-supplement treatments for autism spectrum disorder: a systematic review and network meta-analysis.
- Autism Spectrum Disorder: A Review.
- ω-3 Fatty Acid Supplementation Does Not Affect Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis.
- Does Omega-3 Help After All in Autism Spectrum Disorder? An Update Systematic Review and Meta-Analysis of Randomized Trials.
- The effect of vitamin D supplementation in treatment of children with autism spectrum disorder: a systematic review and meta-analysis of randomized controlled trials.
- Effects of Vitamin D Supplementation on Children with Autism Spectrum Disorder: A Systematic Review and Meta-analysis.
- Sulforaphane treatment of autism spectrum disorder (ASD).
- Randomized controlled trial of sulforaphane and metabolite discovery in children with Autism Spectrum Disorder.
- Sulforaphane Treatment in Children with Autism: A Prospective Randomized Double-Blind Study.
- Efficacy of Sulforaphane in Treatment of Children with Autism Spectrum Disorder: A Randomized Double-Blind Placebo-Controlled Multi-center Trial.
- Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial.
- Folinic acid improves the score of Autism in the EFFET placebo-controlled randomized trial.
- Retraction Note: Efficacy of oral folinic acid supplementation in children with autism spectrum disorder: a randomized double-blind, placebo-controlled trial.
- Folate in autism neurodevelopment.
- The impact of probiotics on core autism symptoms - A systematic review and meta-analysis of randomized clinical trials.
- Probiotics for autism spectrum disorder: An updated systematic review and meta-analysis of effects on symptoms.
- Effectiveness of N-acetylcysteine in autism spectrum disorders: A meta-analysis of randomized controlled trials.
- Efficacy and Safety of Pediatric Prolonged-Release Melatonin for Insomnia in Children With Autism Spectrum Disorder.
- Sleep Disorders in Children and Adolescents with Autism Spectrum Disorder: Diagnosis, Epidemiology, and Management.
- Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content.