Recruiting
Phase 2

N-acetylcysteine

Sponsor:

Stanford University

Code:

NCT04278898

Conditions

Autism Spectrum Disorder

Eligibility Criteria

Sex: All

Age: 3 - 12

Healthy Volunteers: Not accepted

Interventions

N-Acetylcysteine

Study Details

Brief summary:

The goal of this study is to target the neurobiology of restricted and repetitive behaviors in children with autism spectrum disorder using N-acetylcysteine (NAC), a well-tolerated nutritional supplement that has shown promise for reducing symptom severity in recent small-scale trials. The findings from this research will shed light on the mechanisms of action underlying the clinical benefits of NAC.

Conditions

Autism Spectrum Disorder

Study ID

NCT04278898

Start date

Feb 12, 2021

Status verified date

May, 2026

Completion date

Jan 31, 2029

Anticipated

Primary completion date

Jul 31, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 3 - 12

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • children between 3 years and 12 years 11 months at the time of consent
  • diagnosis of Autism Spectrum Disorder confirmed with the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule-2 (ADOS-2), or Brief Observation of Symptoms of Autism (BOSA), or Childhood Autism Rating Scale- Second Edition (CARS-2).
  • at least moderate Restricted and Repetitive Behaviors severity defined by a Children's Yale-Brown Obsessive Compulsive Scale for children with autism spectrum disorder score ≥ 11,
  • physical development indicative of prepubescence as defined by the criteria for Tanner Stage 1,
  • medically stable,
  • passes MR safety screening (e.g., no metal in the body).

Exclusion Criteria:

  • presence of known genetic abnormalities associated with Autism Spectrum Disorder (e.g. Fragile X),
  • current or life-time diagnosis of severe psychiatric disorder (e.g., schizophrenia),
  • presence of significant medical problems that would interfere with participation,
  • the inability of at least one caregiver to speak/read English to a sufficient level to complete study requirements and materials,
  • individuals taking antioxidant agents and glutathione prodrugs, or
  • the inability/unwillingness to swallow an agent during the screening visit.

Study Design

Enrollment

24 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: N-acetylcysteine then Placebo

experimental: Placebo then N-acetylcysteine

Interventions

N-Acetylcysteine

N-acetylcysteine Single Dose 2700 mg taken orally

Primary outcome measure

  • Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI) [ Time Frame: 1 hour after single dose ]

Central Contacts and Locations

Central contacts

Ramy Chebbo

(650) 723-7845autismresearch@stanford.edu

John Hegarty, PhD

(650) 723-7845hegartyj@stanford.edu

Locations

Stanford University School of Medicine

Recruiting

Stanford, California, United States, 94305

Contacts

Ramy Chebbo

(650) 723-7845autismresearch@stanford.edu

Hegarty, PhD

(650) 723-7845hegartyj@stanford.edu

More Information

Sponsor

Stanford University

Last update posted

May 15, 2026

Last verified

May, 2026

Keywords

  • Magnetic Resonance Imaging
  • N-acetylcysteine
  • Restricted and Repetitive Behaviors
  • electroencephalography

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Stanford University on 2026-05-15.