A blinded placebo-controlled randomized trial on the use of astaxanthin as an adjunct to splinting in the treatment of carpal tunnel syndrome.

Background: Nutritional supplementation is a potential adjunct in the conservative management of carpal tunnel syndrome (CTS). This study investigated whether astaxanthin (a beta-carotenoid) increased the effectiveness of splinting in managing CTS.

Methods: This is a triple-blinded randomized controlled trial where 63 patients with electrodiagnostically confirmed CTS were randomly allocated into either the experimental group (n = 32) (astaxanthin-4-mg capsules + splinting) or the control group (n = 31) (placebo + splinting). Medications were taken for 9 weeks followed by a 3-week washout. The primary outcome measure was the Symptom Severity Scale (SSS). Secondary outcome measures in the study included physical impairments, disability, and health status measures. Electrodiagnostic testing was performed before entry into the study and again at 12 weeks. All other outcomes were measured at baseline, 6, and 12 weeks.

Results: There was a reduction in symptoms as measured by the SSS over the course of treatment in both groups (p = 0.002), but no differences between the groups (p = 0.18). The Disability of Arm, Shoulder and Hand questionnaire and the Short Form 36-item Health Survey showed no effects over time or between treatment groups. The baseline difference between the groups in the level of total cholesterol and low-density lipoproteins remained constant over the course of the study. Impairment measures demonstrated no significant changes in grip, dexterity, or sensation.

Conclusion: At present, the role for astaxanthin as an adjunct in conservative management of CTS has not been established.