Background and ObjectivesWhether acupuncture is effective for chronic tension-type headache (CTTH) is inconclusive. We aimed to examine the effectiveness of acupuncture with a follow-up period of 32 weeks.MethodsWe conducted a randomized controlled trial, and 218 participants who were diagnosed with CTTH were recruited from June 2017 to September 2020. The participants in the intervention group received 20 sessions of true acupuncture (TA) over 8 weeks. The acupuncture treatments were standardized across participants, and each acupuncture site was needled to achieve deqi sensation. Each treatment session lasted 30 minutes. The participants in the control group received the same sessions and treatment frequency as those in the superficial acupuncture (SA) group—defined as a type of sham control by avoiding deqi sensation at each acupuncture site. The main outcome was the responder rate at 16 weeks after randomization (week 16) and was followed up at week 32. A responder was defined as a participant who reported at least a 50% reduction in the monthly number of headache days (MHDs).ResultsOur study included 218 participants (mean age: 43.1 years, mean disease duration: 130 months, MHDs: 21.5 days). The responder rate was 68.2% in the TA group (n = 110) vs 48.1% in the SA group (n = 108) at week 16 (OR, 2.65; 95% CI, 1.5 to 4.77; p < 0.001); and it was 68.2% in the TA group vs 50% in the SA group at week 32 (OR, 2.4; 95%CI, 1.36 to 4.3; p < 0.001). The reduction in MHDs was 13.1 ± 9.8 days in the TA group vs 8.8 ± 9.6 days in the SA group at week 16 (mean difference, 4.3 days; 95%CI, 2.0 to 6.5; p < 0.001), and the reduction was 14 ± 10.5 days in the TA group vs 9.5 ± 9.3 days in the SA group at week 32 (mean difference, 4.5 days; 95%CI, 2.1 to 6.8; p < 0.001). Four mild adverse events were reported; 3 in the TA group vs 1in the SA group.DiscussionThe 8-week TA treatment was effective for the prophylaxis of CTTH. Further studies might focus on the cost-effectiveness of the treatment.Trial Registration InformationClinicalTrials.gov: NCT03133884 (clinicaltrials.gov/ct2/show/NCT03133884).Classification of EvidenceThis study provides Class I evidence that acupuncture (achieving deqi sensation) reduces the mean headache days (per month) in patients with CTTH.