THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
Autism, or autism spectrum disorder (ASD), is a lifelong neurodevelopmental difference that affects how a person communicates, interacts, and experiences the world.
6 human studies have tested red light therapy in autism, enrolling 154 participants, and the evidence points to it being effective. The CURE Index assigns this condition 80 out of 100, indicating strong confidence.
Lower scores on standard autism rating scales were linked to red light therapy, in adults as well as children.
Half the studies, 3 of the 6, were randomized controlled trials, alongside 2 clinical trials and 1 observational study. No study in the set reported anything other than an effective outcome.
Courses ran from 28 to 180 days and from 2 to 16 sessions, with each session lasting 12 seconds to 60 minutes. Within a wavelength band of 635 to 1400 nm, 850 nm produced the strongest results.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTH
The wavelength appearing most often in studies that showed benefit for autism.
850 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across autism studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 635-1400 nm |
| Session Duration | 12 seconds-60 minutes |
| Session Frequency | 2-16 per week |
| Therapy Duration | 28-180 days |
6 Human Studies on Red Light Therapy for Autism
Young Children's ASD Scores Decreased 7 Points After Light Therapy
23 children aged 2 to 7 with an existing autism spectrum disorder (ASD) diagnosis took part in a 2025 clinical trial of transcranial photobiomodulation (tPBM). All participants received pulsed 850 nm light at 40 Hz and 150 mW for 2 to 12 minutes per session, directed at language and vision areas of the brain, the front of the brain, and a network active during rest, twice a week across 10 weeks. Average scores on a standard autism rating scale appeared to decrease by 7 points across the treatment period, in a trial that had no comparison group. Brain activity recordings were taken after each session from the children who tolerated wearing the recording cap, and the researchers suggested these might serve as a useful measure in future work.
- Study Type
- Clinical Trial
- Participants
- 23
- Treated Area
- Head
- Wavelength(s)
- 850 nm
- Session Duration
- 2-12 minutes
- Session Frequency
- 2 per week
- Therapy Duration
- 56 days
Study Title: Transcranial photobiomodulation for reducing symptoms of autism spectrum disorder and modulating brain electrophysiology in children aged 2-7: an open label study.
Autism Symptoms Eased More With Pulsed Light Than With Sham
A 2024 randomized controlled trial evaluated transcranial photobiomodulation (tPBM) for autism in children aged 2 to 6. 30 children with an existing autism diagnosis received pulsed near-infrared light at 850 nm and 40 Hz, delivered at 300 mW to selected areas of the brain for 5 to 6 minutes per session, twice a week across 56 days at a university in New Jersey, United States. The trial found that scores on a standard autism rating scale decreased by 7.23 points more in the treated group than in the sham group. The researchers described the approach as one that may be safe and effective, and called for larger studies.
- Study Type
- Randomized Controlled Trial
- Participants
- 30
- Treated Area
- Head
- Wavelength(s)
- 850 nm
- Distance
- Contact
- Session Duration
- 5-6 minutes
- Session Frequency
- 2 per week
- Therapy Duration
- 56 days
Study Title: Transcranial photobiomodulation in children aged 2-6 years: a randomized sham-controlled clinical trial assessing safety, efficacy, and impact on autism spectrum disorder symptoms and brain electrophysiology.
Laser Acupuncture Outperformed the Control Group on ASD Severity Scores
Comparing children who received laser acupuncture against children who did not, a 2023 randomized controlled trial in Egypt examined autism spectrum disorder (ASD) severity, language ability, and blood markers. 30 children were divided equally into the 2 groups, with 1 group receiving 850 nm light at 200 mW and 3 J/cm² for 12 seconds per session across 12 sessions over 42 days, and a separate group of 15 children without ASD taking part only as a comparison for one of the blood measures. According to the trial, severity scores decreased, and language performance rose in both groups, with the larger change in the group given laser acupuncture. A blood marker linked to nerve growth also fell in that group only, and the study described the approach as safe and promising.
- Study Type
- Randomized Controlled Trial
- Participants
- 30
- Treated Area
- Not Specified
- Wavelength(s)
- 850 nm
- Session Duration
- 12 seconds
- Session Frequency
- 12 per week
- Therapy Duration
- 42 days
Study Title: Efficacy of Laser Acupuncture for Children With Autism Spectrum Disorder: Clinical, Molecular, and Biochemical Study.
6 Months of At-Home Light Therapy Lowered Autism Rating Scores
In 2022, an observational study reviewed 6 months of at-home transcranial photobiomodulation (tPBM) in children with autism. 21 children averaging 9 years of age, 13 boys and 8 girls, received 810 nm light at 25 to 100 mW and 15 to 60 J/cm² for 20 minutes per session, applied to areas at the front and middle of the brain and inside the nose, using 2 protocols pulsed at 10 and 40 Hz, across 180 days in Italy. Scores on a standard autism rating scale appeared to decrease at 3 months and again at 6 months, with the decrease continuing between those 2 points. Parent-rated measures of non-compliant behavior, parenting stress, behavioral and mental rigidity, attention, and sleep quality all shifted in the same direction.
- Study Type
- Observational Study
- Participants
- 21
- Treated Area
- Head
- Wavelength(s)
- 810 nm
- Session Duration
- 20 minutes
- Session Frequency
- 10 per week
- Therapy Duration
- 180 days
Study Title: Transcranial Photobiomodulation for the Treatment of Children with Autism Spectrum Disorder (ASD): A Retrospective Study.
Adults With Autism Spectrum Disorder Responded Well to Light Through the Skull
5 of the 10 adults who completed a 2022 clinical trial met the study's criteria for responding to transcranial photobiomodulation (tPBM) for autism spectrum disorder. Participants aged 18 to 59 received 830 nm light at 1 to 2 W and 33.2 mW/cm², delivering 60 J/cm² to the forehead and the front of the head in sessions of 20 to 30 minutes, twice a week across 56 days at a hospital in Boston, United States. The trial found reductions in scores measuring social awareness, social communication, social motivation, and repetitive behavior, alongside higher scores on measures of general functioning and quality of life. 3 participants had mild and short-lived side effects, namely difficulty sleeping, headache, and warmth where the light was applied, and none required any change to the treatment.
- Study Type
- Clinical Trial
- Participants
- 10
- Treated Area
- Head
- Wavelength(s)
- 830 nm
- Session Duration
- 20 minutes, 25 minutes, 30 minutes
- Session Frequency
- 16 per week
- Therapy Duration
- 56 days
Study Title: Transcranial Photobiomodulation in Adults with High-Functioning Autism Spectrum Disorder: Positive Findings from a Proof-of-Concept Study.
Behavior Scores Improved With Laser but Not Placebo in Autism
Irritability scores on a standard behavior checklist decreased 15.17 points further in the treated group than in the placebo group in a 2018 randomized controlled trial of low-level laser therapy (LLLT) for autism. 40 children and adolescents aged 5 to 17 took part, with 21 receiving 8 sessions of 635 nm light at 15 mW for 5 minutes each, applied to the base of the skull and the sides of the head across 28 days, and 19 receiving a placebo procedure. Scores on the checklist's global scale and all 5 of its subscales appeared to decrease steadily across the study, and the gap between the groups was statistically significant. The decrease continued through a 4-week follow-up period during which no further LLLT was given.
- Study Type
- Randomized Controlled Trial
- Participants
- 40
- Treated Area
- Head
- Wavelength(s)
- 635 nm
- Session Duration
- 5 minutes
- Session Frequency
- 8 per week
- Therapy Duration
- 28 days
Study Title: Effects of Low-Level Laser Therapy in Autism Spectrum Disorder.
The CURE Index (Clinical Understanding of Red-light Evidence) by Helio Cure is a 0-100 evidence score based on published human clinical trials. Higher scores mean stronger evidence. Read full methodology →
Data is powered by AI and reviewed by the Helio Cure team.
This page is for educational purposes only. Not medical advice. Consult a healthcare provider before starting red light therapy. Helio Cure does not diagnose, treat, or cure any medical condition.
Last updated: Sep 30, 2026