The goal of this clinical trial is to learn if Ning Shen Dan Xiang paste combined with Ejiao (donkey-hide gelatin) works better than Ning Shen Dan Xiang paste combined with agar (placebo substitute) to treat chronic insomnia of the heart-kidney disharmony type in adults. It will also assess safety. The main question is:
\- Does Ning Shen Dan Xiang + Ejiao improve sleep quality more than the placebo version, as shown by the change in Pittsburgh Sleep Quality Index (PSQI) score after 8 weeks?
Researchers will compare the two pastes (identical in appearance and taste except for Ejiao) and use published literature data as an additional external control.
Participants will:
Take 20 g of the assigned paste twice daily (morning and evening) for 8 weeks. Attend clinic visits at baseline, week 4, week 8, and 1 week after stopping (week 9 follow-up).
Complete PSQI and ISI questionnaires, keep a daily electronic sleep diary, provide blood/stool samples, and undergo safety monitoring (blood/urine tests, ECG, vital signs, and side effect checks).