Red Light Therapy for Bell's Palsy: Scientific Evidence

Across 4 randomized trials, a 2023 review from a dental school in Ribeirão Preto, Brazil, examined laser acupuncture for nerve problems arising in dentistry, including facial paralysis, altered sensation, and nerve pain. The recommended wavelengths ranged from 790 to 810 nm, applied at least twice a week. All 4 studies reported some degree of improvement in the sensory or motor recovery of the facial nerves. The review described laser acupuncture as a viable option in dentistry for treating altered sensation and facial paralysis.

This 2023 observational study followed 3 people whose facial paralysis had persisted despite standard treatment, at a university in Ljubljana, Slovenia. Near-infrared laser light at 1064 nm was applied to 11 trigger and affected points at 500 to 533 mW/cm², 30 to 32 J/cm², 192 J, and 10 Hz for 60 seconds per point, in 22 to 48 sessions across 120 to 180 days. 1 man, 30 years old, had lived with left-sided paralysis for 12 years, and after 9 weeks noticed changes in his cheek, with a marked turning point at 11 weeks when he could whistle and smile again and open his left eye wider. Electrical testing 6 months after treatment ended confirmed the improvement in his facial muscles, though his face remained less than fully symmetrical.

20 of the 60 patients had the whole affected area scanned with the laser, 20 were treated at fixed points, and 20 received a placebo device, in a 2022 randomized controlled trial in Makkah, Saudi Arabia. The trial was double-blind, and all 3 groups also had facial massage and exercises, with the active groups receiving 808 and 905 nm light at 10 J/cm² for 37 seconds per point or about 15 minutes of scanning, across 12 sessions over 42 days. Facial grading and both physical and social disability scores improved significantly in all 3 groups at 3 and 6 weeks. Comparing the groups, the scanning technique produced the greatest effect, followed by point application, with the placebo group improving least.

Researchers at the Ministry of Health in Cairo, Egypt, compared low-level laser against electrical stimulation in a 2022 randomized controlled trial of 45 people with Bell's palsy. Patients were divided into 3 equal groups, with 1 given 850 nm laser light, 1 given electrical stimulation, and 1 given neither, and all 3 also received medication, massage, and facial exercises. Nerve signal size and timing, signs of nerve regrowth, and scores on a standard facial grading system all differed significantly between the 3 groups in favor of the laser group. The trial concluded that laser was the more efficient of the 2 treatments for facial nerve regrowth over the short term.

According to a 2021 observational study from a dental faculty in Nice, France, a 15-year-old girl treated herself at home and recovered completely from Bell's palsy within 2 weeks. She had acute pain on the right side of her face, difficulty biting, and saliva dripping from the right side of her lips when she began. She applied 808 nm near-infrared laser light to the skin over the salivary gland twice a day for 15 minutes per session at 250 mW, 48 J/cm², 14.4 J, and 15000 Hz, across 14 days. No medicines were taken alongside it, and no side effects followed.

Recovery of movement was recorded by the middle of the course and again at the end, according to a 2020 observational study of light therapy for 1 patient with facial paralysis of 8 years' standing. The patient in São Paulo, Brazil, received 660 and 808 nm light on the affected side only at 200 mW, 2020 mW/cm², 40.65 and 60.97 J/cm², and 4 to 6 J for 20 to 30 seconds per point, 3 times a week across 56 days. Assessments were made before treatment, after the 12th session, and after the 24th, using a standard facial grading scale and electrical testing of the nerve and muscles. The study described the treatment as effective and non-invasive in this long-standing case.

30 people with poorly controlled diabetes and facial paralysis, 18 women and 12 men, were treated in a 2020 clinical trial at a medical center in Tabriz, Iran. Each received 830 and 980 nm light in contact with the skin at 334 mW, 16 J/cm², 5 J, and 100 Hz for 60 seconds at points across the affected side of the face, including behind the ear, across 12 sessions over 28 days. At the 3-month assessment, 18 patients had recovered completely, and 6 had recovered partially. The trial described the approach as a safe and suitable option where an underlying condition such as diabetes is present.

By the 5th of 10 sessions, the patient's recovery was described as remarkable, in a 2020 observational study of laser light used on its own for facial paralysis in São Paulo, Brazil. Treatment used 808 nm low-level laser light at 100 mW, 120 J/cm², and 3.3 J for 10 seconds at each point, given once every 48 hours at first and twice weekly after the 5th session, across 47 days. No other treatment of any kind was given alongside it. By the end of the course, the patient scored the top grade on a standard facial function scale, and follow-up over the months afterward found no lasting effects and no recurrence.

After 12 years of severe left-sided facial paralysis following an injury, a 52-year-old man received 30 sessions of laser acupuncture in a 2019 observational study in Taichung, Taiwan. He could not fully close his left eye, had difficulty eating solid food, and had developed slurred speech. He was treated with 810 nm light at 200 mW, 200 mW/cm², 45 J/cm², and 3 to 6 J for 30 to 60 seconds at points on the affected side of his face and at points on his hands and feet, across 119 days. A change in how far his left eye would close was noticed at the 10th treatment, alongside stronger facial muscles. By the 22nd treatment, he could close the eye fully.

In 2018, an observational study in Alfenas, Brazil, described a 13-year-old girl who could not smile on the right side, close her right eye, or raise her right eyebrow, and who had severe pain, difficulty chewing and talking, and drooling. She was treated with 830 nm light at 100 mW, 100 J/cm², and 5.6 J for 28 seconds at each point over the chewing muscle on the affected side, across 3 sessions over 21 days. Her facial movement and her pain both improved after those 3 sessions. The study described the approach as effective and free of side effects, while noting that no settled protocol yet exists.

A 2-group design in a 2017 randomized controlled trial added low-level laser to facial exercises for 46 people with facial paralysis in Konya, Turkey. 40 women and 6 men with an average age of 41 took part, with 1 group receiving 830 nm light at 100 mW, 10 J/cm², 80 J, and 1000 Hz for 2 minutes per session, 3 times a week across 42 days alongside the exercises, and the other doing the exercises alone. Facial disability scores improved significantly in the laser group at both 3 and 6 weeks, while the exercise group improved significantly only at 6 weeks. The difference between the groups favored the laser group significantly at both time points.

Comparing high-intensity laser, low-level laser, and exercise alone, a 2014 randomized controlled trial examined recovery in 48 patients with Bell's palsy, average age 43, at a university in Cairo, Egypt. All 3 groups received facial massage and exercises, with the 2 laser groups additionally treated at 8 points on the affected side of the face 3 times a week across 42 days, using 1064 nm at up to 3000 W in 7-second bursts or 830 nm at 100 mW and 10 J/cm² for about 2 minutes. Both laser groups improved significantly on scales of facial disability and facial function, as did the exercise group. Comparing the groups at 3 weeks, the high-intensity laser group improved most, followed by the low-level laser group, with the exercise group improving least.

A 40-year-old man reported 70% to 80% better facial movement after a single treatment in a 2013 observational study from a clinic in Joliet, Illinois, United States. He had had left-sided facial paralysis for 10 days, could not close his left eye, and had trouble lifting his lip and controlling saliva, having already been given oral steroids. Treatment combined 910 nm low-level laser light with chiropractic manipulation, given twice over 4 days, with the light applied for 30 seconds at each point along the facial nerve and for 60 seconds behind the ear at 100 W and 20000 Hz. After the second treatment, he reported full control of his facial movements.

A 3-year-old boy with a sudden loss of movement on the right side of his face took part in a 2013 observational study in Araraquara, Brazil. He received 660 and 780 nm low-level laser light in contact with the skin at 40 to 60 mW and 12.5 J/cm², applied for 10 seconds at each of up to 80 points across the affected side, in sessions of 15 to 30 minutes given 4 times a week at first, across 21 days. No steroids or other medicines were given at any point. After 11 sessions, his facial movement and symmetry had returned completely to normal.

A 2000 observational study treated 103 patients with facial nerve damage using infrared laser acupuncture alongside homeopathy. Light at 890 nm and 15 mW/cm² was applied to acupuncture points, and the homeopathic preparations were chosen to address each patient's constitution and symptoms. All 103 patients appeared to benefit from the treatment. Electrical tests of nerve function and acupuncture-based assessment were used to confirm that finding, and both parts of the treatment were given together throughout.

Researchers treated 87 patients with facial nerve inflammation using infrared laser acupuncture as part of a broader treatment program, in a 1997 observational study. Light at 890 nm and 20 mW was applied to 10 to 15 acupuncture points per session for 1 to 3 minutes each, with the points chosen according to traditional Chinese medicine and a course running to 12 to 16 sessions. The study reported a good clinical effect across the group. Electrical tests of nerve function were used to confirm it.

In 2024, a meta-analysis from a dental school in Tokyo, Japan, drew together 7 studies from 519 articles identified, covering 306 patients with recent Bell's palsy. The included studies used wavelengths from 600 to 1600 nm at 60 mW to 10 W and 1 to 14 J/cm², given as 15 to 30 sessions over 15 to 42 days. Pooled scores on 1 standard facial grading system favored laser therapy significantly, with an average difference of 17.42 points. Scores on a standard questionnaire measuring how much facial palsy limits daily and social activity did not differ significantly between laser and control, and 2 of the 7 studies could not be pooled at all for lack of the necessary figures.

Across 6 months of follow-up, a 2023 clinical trial in Beijing, China, tested light therapy added to standard care for Bell's palsy that had already lasted more than 8 weeks. 54 patients were divided into 27 given the added light and 27 not, with the comparison group recruited during 2020 and the treated group during 2021 and 2022, using 808 nm at 1 W continuously and 905 nm at 200 mW in pulses to deliver 8.35 J/cm² 3 times a week across 72 sessions over 180 days. Scores on 2 standard facial grading systems differed significantly between the groups after 6 months. A patient-rated quality of life scale did not reach significance, and 1 of the nerve timing measures did not either, though most of the electrical tests did.

Disability scores showed no significant change from the start to 6 weeks in a 2021 randomized controlled trial of laser acupuncture for people whose Bell's palsy had not fully resolved. 17 patients in Taichung, Taiwan, received 810 nm light at 150 mW/cm², 3 and 6 J, and 584 and 4672 Hz for 40 or 80 seconds at points on the face, arms, and legs, in 18 sessions over 42 days, against a sham procedure. Scores on a standard facial grading scale did improve significantly between the start and week 3. Scores on a second facial grading system and on a stiffness scale came close to significance at 6 weeks without reaching it.

Searching 3 research databases without limiting by language, a 2020 review assessed low-level laser therapy for Bell's palsy at a university in Tehran, Iran. 4 studies of 259 met the criteria, covering 171 patients all treated within a week of onset, using 660 to 830 nm light at 100 mW and 1 to 100 J/cm². Both the laser and control groups improved significantly in every trial. 2 of the 4 reported a significant difference between the groups after 6 weeks at 830 nm and 100 mW, while the other 2 found no difference after 4 weeks and after 15 days, and no adverse effects were reported in any of them.

95% improvement was reported by 1 patient and 50% by the other in a 2014 observational study of infrared light at a chiropractic clinic in Hong Kong, China. A 32-year-old man treated 1 day after onset received 19 sessions across 6 weeks, while a 46-year-old woman who had already had 18 months of corticosteroid and electro-acupuncture treatment received 45 sessions across 9 months. Both were treated with 890 nm light for 30 minutes per session, applied in front of and behind the ear and to the temple and jaw on the affected side. The study noted that 71% of people with Bell's palsy recover without any treatment at all, and concluded that it could describe the course of care but could not confirm that the light was responsible.