The effectiveness of Multiwave Locked System (MLS) laser therapy was evaluated in a total of 30 patients, aged more than 20 years old with mild to moderate carpal tunnel syndrome (CTS) with a single-blinded randomized controlled study. 
The patients were randomly assigned into intervention and control groups. The intervention group received 12 sessions of MLS laser treatment at a dosage of 15.01 J/cm² per session over the carpal tunnel area and thenar area innervated from median nerve and conventional rehabilitation treatment. The control group received placebo laser therapy that consisted of red light from flashlights covered with red cellophane without laser power output shined over the region, duration and frequency same as 
the intervention group. The patients were evaluated with the following parameters: (1) clinical parameters which consisted of symptom severity scale (SSS), functional status scale (FSS), visual analog scale (VAS) and EQ-5D-5L before treatment and follow-ups at 4 and 12 weeks, (2) electrophysiological parameters which were evaluated before treatment and follow-up at 12 weeks and (3) assessment for satisfaction of the service at 4 and 12 weeks. Thirty patients (52 hands: unilateral CTS=8 hands and bilateral CTS=44 hands) completed the study. Both groups had n=15 patients. The improvements were significantly more pronounced in the intervention group than control group (p<0.05) especially for VAS and Compound muscle action potential (CMAP) amplitude of the median nerve at 12 weeks follow-up. MLS laser therapy coupled with conventional rehabilitation treatments is an effective treatment option in mild to moderate degree CTS before proceeding to surgery. It can clinically improve especially for VAS and electrophysiological parameter with a carry-over effect up to 3 months.