Red Light Therapy for Herniated Disc: Scientific Evidence

In 2025, a single-blind randomized controlled trial in China tested high-intensity laser therapy added to an injection that dissolves part of a slipped disc. 60 patients, average age 57 and about half of them men, were randomly assigned in equal numbers, with 1 group receiving 890 and 910 nm light at 15 W and 10 J/cm² for 4 to 6 minutes a session across 5 days after the injection, and the other receiving the injection with a switched-off laser. The trial concluded that adding the laser improved pain and daily function in the early period after the procedure. That advantage had diminished by 3 months, which the trial read as the combination speeding up early recovery rather than changing the longer-term outcome.

A 2018 randomized controlled trial evaluated high-intensity laser therapy added to a spine-stretching machine for a bulging disc in the lower back. 63 patients in China were divided into 2 groups, with 32 receiving 1064 nm light at 12 W, 150 J/cm², and 7500 J for 10 minutes per session across 10 sessions over 14 days alongside the machine, and 31 receiving the machine alone. Daily function, forward bending, and straight-leg raising appeared to improve more in the group given the added laser. Pain scores improved in both groups, but the difference between them did not reach statistical significance.

A 3-group design compared laser light, LED light, and a placebo device in a 2016 randomized controlled trial of a slipped disc in the lower back. 49 people in Brazil, 25 men and 24 women, completed the trial, with 18 receiving 904 nm laser light, 18 receiving 945 nm LED light, and 13 receiving the placebo, each delivering 4 J to 12 points along the lower spine and 8 points on the affected thigh, for 13.33 and 34.67 minutes per session across 15 daily sessions over 21 days. Every group performed the same leg-flexion exercises after each session, and the trial found that all 3 improved significantly in back pain, leg pain, hip movement, and daily function. The difference between groups reached statistical significance for leg pain, walking difficulty, and daily function, with the LED group ahead and the 904 nm laser showing no advantage.

26 outpatients with long-standing neck pain caused by a herniated disc in the neck took part in a 2012 observational study of low-level laser therapy (LLLT). Each received 830 nm light from a 1000 mW device delivering 20.1 J/cm² per point, with 3 points treated per session for 2 to 3 minutes, twice a week across 28 days, applied to the muscles alongside the neck. Pain scores on a standard rating scale improved significantly by the end of the course, while neck movement showed no meaningful change. The report noted that maintaining the benefit depended on patients learning to avoid the postures that brought on the pain.

No advantage over a placebo device followed treatment in a 2010 double-blind randomized controlled trial of low level laser therapy (LLLT) for back pain caused by a herniated disc in the lower back. 80 patients in Turkey, 46 women and 34 men, were divided into 4 groups of 20, split by whether their pain was recent or long-standing and by whether they received real or placebo laser, with all 4 groups also receiving a hot pack. The active groups received 850 nm light at 100 mW and 40 J/cm² for 4 minutes per session across 15 sessions over 21 days. The trial found significant improvement in pain, movement, and daily function in all 4 groups, with no significant difference between any of them.