Inclusion Criteria:
1. Subjects meeting the clinical diagnostic criteria for chronic insomnia disorder.
2. Subjects meeting the TCM differentiation criteria for syndrome of yin deficiency with effulgent fire and disharmony between heart and kidney.
3. Aged from 18 to 65 years old (both endpoints included).
4. Disease duration ≥ 3 months, with insomnia occurring ≥3 days per week. The habitual time in bed (time spent sleeping or attempting to fall asleep) ranges from 7 to 9 hours, accompanied by subjectively perceived sleep distress (complaints of dissatisfaction with nighttime sleep, manifested as difficulty falling asleep, difficulty maintaining sleep, and/or waking up earlier than expected in the morning).
5. At least one daytime symptom associated with nighttime sleep disturbance (fatigue, depressed mood or irritability, physical discomfort, cognitive impairment, anxiety, etc.).
6. Insomnia Severity Index (ISI) score ≥ 8 at the end of the placebo run-in period.
7. During the consecutive 7-day sleep diary recording at the end of placebo run-in period, there are at least 3 days meeting: subjective sleep onset latency (sSOL) ≥30 minutes, subjective wake after sleep onset (sWASO) ≥30 minutes, and subjective total sleep time (sTST) \<6.5 hours.
8. Able to cooperate and independently complete scale assessments and recordings.
9. Able to understand and voluntarily sign the informed consent form.
Exclusion Criteria:
1. History of sleep-related breathing disorders including chronic obstructive pulmonary disease, obstructive sleep apnea (with or without continuous positive airway pressure \[CPAP\] treatment), periodic limb movement disorder, myasthenia gravis, restless legs syndrome, circadian rhythm sleep-wake disorders, narcolepsy or other sleep disorders. Subjects with cured diseases mentioned above can be enrolled.
2. Insomnia caused by other conditions such as chronic pain, headache, psychiatric disorders, malignant tumors, eczema, neurodermatitis, allergic rhinitis, severe dermatitis (sleep difficulty due to physical conditions or medical causes).
3. Nocturia induced or aggravated by urinary tract infection, trauma, prostate diseases and other conditions.
4. Previous complex sleep behaviors, such as sleep driving, sleep-related eating disorder, sleep calling and other behaviors.
5. Daily excessive intake of tea or caffeinated beverages (defined as more than 4 cups of caffeinated drinks per day or caffeine intake\>400 mg per day), or habitual consumption of caffeinated food or beverages after 18:00. If assessed as the main contributing factor for insomnia and expected to maintain such intake after enrollment.
6. More than 10 cigarettes per day within 6 months before screening, or uncontrollable smoking before bedtime, and expected to smoke more than 10 cigarettes daily after enrollment.
7. Any lifestyle that interferes with trial progress or sleep assessment: cross-timezone travel across ≥3 time zones (Chinese mainland counts as one time zone) or shift work (alternating day and night shifts) within the recent two weeks or during the trial period.
8. Depression: Hamilton Depression Scale (HAMD) score ≥18; Anxiety: Hamilton Anxiety Scale (HAMA) score ≥14; or subjects with suicidal ideation or behaviors.
9. Subjects with severe endocrine diseases, hematological diseases, cardiovascular and cerebrovascular diseases, gastrointestinal diseases, liver and kidney diseases, autoimmune diseases, neuropsychiatric diseases, impaired respiratory function, or other medical histories considered by researchers that may affect subject safety or interfere with study evaluation.
10. Plan to receive surgical operations during the study period.
11. History of drug abuse, or positive result in any item of urine drug screening; history of drug addiction, drug use, alcohol dependence or abuse.
12. Allergy to the investigational product or its ingredients.
13. Participation in other drug clinical trials and receiving investigational products within 1 month or 5 half-lives (whichever is longer) before screening, or concurrent participation in other research trials during this trial.
14. Pregnant or lactating women.
15. Other conditions judged by researchers making the subject inappropriate to participate in this clinical trial.
