THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
Mild cognitive impairment is a condition that causes mild but noticeable problems with memory and thinking skills, while daily independence is usually preserved.
A review of 5 human studies covering 178 participants found red light therapy to be effective for mild cognitive impairment. The CURE Index scored this condition 98 out of 100, indicating strong confidence.
Red light therapy was associated with improvements in memory, thinking skills, and blood flow to the brain across the studies reviewed for mild cognitive impairment.
The 5 studies included 3 randomized controlled trials, 1 clinical trial, and 1 observational study. All 5 studies reported effective outcomes for mild cognitive impairment.
810 nm was reported as the most cited wavelength, with studies using wavelengths ranging from 610 to 1400 nm. Session durations ranged from 10 to 30 minutes, session frequency ranged from 5 to 72 times per week, and therapy duration ranged from 5 to 84 days.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTH
The wavelength appearing most often in studies that showed benefit for mild cognitive impairment.
810 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across mild cognitive impairment studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 610-1400 nm |
| Session Duration | 10-30 minutes |
| Session Frequency | 5-72 per week |
| Therapy Duration | 5-84 days |
Note: We have excluded meta-analyses and reviews from scoring, but the list of human studies below contains them for your reference.
6 Human Studies on Red Light Therapy for Mild Cognitive Impairment (MCI)
MCI Due to Alzheimer's Showed Cognitive Improvement With Home tPBM
Cognitive scores improved significantly in the transcranial photobiomodulation (tPBM) group compared with the sham group in a 2025 randomized, sham-controlled trial for mild cognitive impairment (MCI) due to Alzheimer's disease. The trial enrolled 26 participants who were assigned to either the tPBM group or the sham group, with the tPBM group receiving 808 nm light to the front part of the brain behind the forehead for 11.12 minutes per session, six times per week over 12 weeks. Researchers also noted improvement on a second cognitive test called the Mini-Mental State Examination in the tPBM group, though this difference did not reach statistical significance. The study reported no serious adverse events during treatment.
- Study Type
- Randomized Controlled Trial
- Participants
- 26
- Treated Area
- Brain
- Wavelength(s)
- 808 nm
- Distance
- Contact
- Session Duration
- 11.12 minutes
- Session Frequency
- 72 per week
- Therapy Duration
- 84 days
Study Title: The Efficacy and Safety of Transcranial Photobiomodulation for Mild Cognitive Impairment Due to Alzheimer's Disease: A Randomized, Double-Blind, Sham-Controlled Study.
Photobiomodulation Outperformed Placebo for Cognition in Mild Cognitive Impairment
Researchers in 2024 tested transcranial photobiomodulation (t-PBM) against a placebo in older adults with mild cognitive impairment (MCI), in a randomized, double-blind, placebo-controlled trial, to see its effect on thinking skills and blood markers linked to brain health. The trial included 93 adults over 50 years old with MCI, randomly assigned to a t-PBM group of 47 participants or a placebo group of 46 participants, of whom 76 completed the study through follow-up. Participants received invisible near-infrared light between 780 and 1400 nm applied to the scalp, with checkups at the start, at 60 days, and at a 150 day follow-up. Researchers reported no differences between groups in mood, anxiety, resilience, or two blood markers of brain cell health. They found that the t-PBM group showed greater improvement in thinking skills on a memory and thinking test called the Montreal Cognitive Assessment, along with a greater increase in a blood marker linked to brain cell growth called BDNF, compared with the placebo group.
- Study Type
- Randomized Controlled Trial
- Participants
- 93
- Treated Area
- Head
- Wavelength(s)
- 780-1400 nm
Study Title: Transcranial photobiomodulation increases cognition and serum BDNF levels in adults over 50 years: A randomized, double-blind, placebo-controlled trial.
Cognitive Function Improved in Older Adults With MCI After Photobiomodulation
3 older adults with non-amnestic mild cognitive impairment showed improvements in frontal lobe cognitive function after receiving transcranial photobiomodulation (tPBM) in a 2022 observational study. The treatment targeted the frontal lobe with 810 nm light at a light intensity of 20 mW per cm2, delivering a light dose of 21 J per cm2 across 18 sessions of 17.5 minutes each over 9 weeks. Improvements in frontal lobe cognitive function and reductions in depressive and anxiety symptoms were reported among the three participants after treatment, though the very small sample size means these findings should be considered preliminary.
- Study Type
- Observational Study
- Participants
- 3
- Treated Area
- Brain
- Wavelength(s)
- 810 nm
- Session Duration
- 17.5 minutes
- Therapy Duration
- 63, 126 days
Study Title: Photobiomodulation improves frontal lobe cognitive functions and mental health of older adults with non-amnestic mild cognitive impairment: Case studies.
TPBM Improved Attention and Cognition in Older Women With MCI
A randomized controlled trial published in 2022 evaluated the effect of transcranial photobiomodulation (tPBM) on cognitive function and attention in older women with mild cognitive impairment (MCI). The study included 42 older women with MCI who were randomly assigned to a real tPBM group or a sham group, with the real group receiving light between 850 and 870 nm to the forehead for 10 minutes per session, 5 sessions per week over 5 days, at an irradiance of 285 mW per cm2 and a fluence of 42.75 J per cm2. Researchers reported that the real tPBM group showed improved scores on a standard memory and thinking test called the Mini-Mental State Examination (MMSE) and performed better on an attention test called the Go/No-Go task, compared with the sham group, suggesting tPBM may support cognitive and attentional function in older adults with MCI.
- Study Type
- Randomized Controlled Trial
- Participants
- 42
- Treated Area
- Head
- Wavelength(s)
- 850-870 nm
- Session Duration
- 10 minutes
- Session Frequency
- 5 per week
- Therapy Duration
- 5 days
Study Title: The effect of transcranial photobiomodulation on cognitive function and attentional performance of older women with mild cognitive impairment: a randomized controlled trial.
Mild Cognitive Impairment Patients Reported Better Memory After Photobiomodulation
When researchers examined photobiomodulation (PBM) for mild cognitive impairment in a 2021 uncontrolled pilot clinical trial, they measured its effect on blood flow to the brain and thinking skills. Fourteen patients received PBM to the neck over the arteries that carry blood to the brain, using 610 nm light at a light intensity of 3 mW per cm2 and an output power of 2.5 W, applied for 30 minutes per session. Researchers found that this treatment was associated with improvements in blood flow to several brain regions involved in thinking, along with gains in overall cognitive function, memory, and planning and decision making skills, though the findings come from a small trial without a comparison group and need confirmation in larger studies.
- Study Type
- Clinical Trial
- Participants
- 14
- Treated Area
- Neck
- Wavelength(s)
- 610 nm
- Session Duration
- 30 minutes
- Therapy Duration
- 56, 280 days
Study Title: Effects of Photobiomodulation on Changes in Cognitive Function and Regional Cerebral Blood Flow in Patients with Mild Cognitive Impairment: A Pilot Uncontrolled Trial.
Combined Photobiomodulation Reversed Cognitive Decline in MCI Case Report
A 2020 narrative review described a case in which combined photobiomodulation therapy (PBMT), applied to the scalp and inside the nose, was associated with a rapid reversal of cognitive decline in a patient with mild cognitive impairment (MCI). The patient received a nasal LED device delivering 810 nm light into the left nostril, combined with a light emitting helmet worn on the head, twice daily for 1 month, at a light dose of 10.65 J per cm2 delivered at a pulse rate of 10 times per second. The review reported that this combination therapy was associated with improved cognitive performance and a reversal of smell related impairment in the patient, though the findings are based on a single case and need confirmation in larger studies.
- Study Type
- Review
- Treated Area
- Nose
- Wavelength(s)
- 400-540, 420, 532, 632.8, 633, 650, 658, 670, 671, 808, 810, 830, 1064 nm
- Distance
- Contact
- Session Duration
- 15 minutes, 30 minutes, 60 minutes
- Session Frequency
- 10, 20 per week
- Therapy Duration
- 10, 14, 84, 365 days
Study Title: Therapeutic potential of intranasal photobiomodulation therapy for neurological and neuropsychiatric disorders: a narrative review.
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: Jul 20, 2026