This multicenter, randomized, sham-controlled clinical trial will evaluate the efficacy and safety of acupuncture for patients with subjective idiopathic tinnitus. A total of 226 eligible participants will be randomly assigned to receive either acupuncture or sham acupuncture. Both groups will receive treatment for 5 weeks. The primary outcome is the change in Tinnitus Handicap Inventory score from baseline to Week 5. Secondary outcomes include tinnitus loudness, tinnitus severity, sleep quality, anxiety, depression, audiological assessments, and adverse events. Exploratory neuroimaging outcomes include functional magnetic resonance imaging and magnetoencephalography measures.

Subjective idiopathic tinnitus is a common otologic condition that may be associated with sleep disturbance, anxiety, depression, and reduced quality of life. Current treatment options often provide limited symptom relief, and high-quality evidence for acupuncture in tinnitus remains insufficient.

This study is designed as a multicenter, randomized, sham-controlled clinical trial to compare acupuncture with non-penetrating sham acupuncture in patients with chronic subjective idiopathic tinnitus. Eligible participants will be adults aged 18 to 80 years with tinnitus as the primary complaint, tinnitus duration of at least 6 months, and a baseline Tinnitus Handicap Inventory score of 38 or higher.

Participants will be randomly assigned in a 1:1 ratio to the acupuncture group or the sham acupuncture group. The acupuncture group will receive standardized acupuncture treatment based on the therapeutic principle of invigorating the spleen, tonifying the kidney, and opening the orifices. The sham acupuncture group will receive non-penetrating sham acupuncture at the same acupoints. Both groups will receive treatment for 5 weeks and tinnitus-related health education.

Participants will be assessed at baseline, during treatment, at the end of treatment, and during post-treatment follow-up. The primary endpoint is the change in Tinnitus Handicap Inventory score from baseline to Week 5. Secondary outcomes include tinnitus-related visual analog scale scores, Pittsburgh Sleep Quality Index, Self-Rating Anxiety Scale, Self-Rating Depression Scale, pure tone audiometry, tinnitus matching, distortion product otoacoustic emissions, and adverse events. Exploratory outcomes include changes in brain functional connectivity measured by functional magnetic resonance imaging and brain power spectral density measured by magnetoencephalography.

Inclusion Criteria:

1. Tinnitus as the primary complaint, meeting the diagnostic criteria for subjective idiopathic tinnitus.
2. Tinnitus duration of at least 6 months.
3. Patent external auditory canal and intact tympanic membrane.
4. Bilateral pure tone average no greater than 80 decibels hearing level (dB HL).
5. No contraindications to MRI or MEG scanning, such as claustrophobia or metallic implants.
6. Age 18 to 80 years.
7. Right-handed.
8. Baseline Tinnitus Handicap Inventory score of 38 or higher.
9. Able to understand and complete examinations, assessments, and treatment procedures under physician guidance.
10. Willing to participate and able to provide written informed consent before treatment.

Exclusion Criteria:

1. Inner ear or auditory nerve disorders, including sudden sensorineural hearing loss, Meniere disease, otosclerosis, or acoustic neuroma.
2. External or middle ear diseases, including otitis externa, foreign body in the external auditory canal, eczema of the external auditory canal, cerumen impaction, acute or chronic otitis media with effusion, or acute or chronic suppurative otitis media.
3. Non-otogenic tinnitus caused by acute or chronic systemic diseases involving hematologic, endocrine, renal, or other major organ systems.
4. Objective tinnitus, including myogenic, vascular, or patulous eustachian tube-related tinnitus.
5. Cognitive impairment or tinnitus caused by other neurological diseases, including stroke, epilepsy, traumatic brain injury, severe headache history, severe central ischemia, brain tumor, neurasthenia, or post-neurosurgical tinnitus.
6. Severe cardiovascular or cerebrovascular disease, intracranial space-occupying disease, tumor, or severe pulmonary, hepatic, renal, or hematopoietic disease.
7. Pregnancy or lactation.
8. Psychiatric disease, impaired consciousness, or inability to cooperate with examinations or treatment.
9. Participation in another conflicting clinical trial within 6 months before enrollment or currently participating in another conflicting clinical trial.

Individual participant data will not be shared because the current ethics approval and informed consent do not include a plan for external sharing of de-identified individual participant data. Aggregate study results may be disseminated through academic publications.

Participants and outcome assessors will be masked to group allocation. Acupuncturists cannot be masked due to the nature of the intervention. Randomization personnel will not participate in treatment, outcome assessment, or statistical analysis. Data analysts will remain blinded until the primary analysis is completed.