Background: Omega-3 fatty acids have anti-inflammatory and neuroprotective effects. However, there is no clinical trial to evaluate the efficacy of omega-3 fatty acids in the treatment of carpal tunnel syndrome (CTS).

Objective: To study the efficacy of omega-3 fatty acids (1,200 and 3,000 mg) administration compared with conventional treatment for three months in patients with mild to moderate CTS.

Materials and Methods: A randomized double-blind controlled trial was conducted in Thammasat University Hospital, Thailand between March 2017 and December 2018. Patients with mild to moderate CTS were randomly assigned into three treatments: 1) oral fish oil, EPA/DHA 1,200 mg per day, 2) fish oil 3,000 mg per day, and 3) placebo. All patients received vitamin B as a conventional treatment. Patients and research assistant who gave a concealed container were blinded to the group assignment. The primary outcomes were numbness and pain scores, which were measured monthly in numeric rating scale (NRS 0 to 10) for three months. Linear mixed models were used to analyze correlated data.

Results: Twenty-eight patients with 42 CTS hands were analyzed: 1) fish oil 1,200 mg group (n = 9, hand = 13), 2) fish oil 3,000 mg group (n = 10, hand = 16), and 3) control group (n=9, hand=13). A duration of symptoms was the only different variable between the three groups in univariable analysis. After adjustment for duration of symptoms, the mean differences of numbness and pain score were monthly reduced 0.6 points (95% CI –1.2 to –0.1, p=0.017) and 0.8 points (95% CI –1.3 to –0.2, p = 0.005), respectively, in the fish oil 3,000 mg group compared with the control group. However, there was no statistically significant difference in any score between the fish oil 1,200 mg group and the control group. Heartburn and abdominal discomfort were found similarly in the three groups. There were no serious side effects in the present study.

Conclusion: Omega-3 fatty acids (EPA/DHA 3,000 mg per day) reduce numbness and pain with statistical significant difference in treatment of mild to moderate CTS. However, clinical significance was still in doubt and need further research to explore.