PURPOSEIt is unclear whether traditional Chinese patent medicines can resist premature aging. This prospective study investigated the effects of Bazi Bushen Capsule (BZBS) which is a traditional Chinese patent medicine for tonifying the kidney essence on premature senility symptoms and quality of life, telomerase activity and telomere length.STUDY DESIGN AND METHODSIt was a parallel, multicenter, double-blind, randomized, and placebo-controlled trial. Subjects (n = 530) aged 30-78 years were randomized to receive BZBS or placebo capsules 12 weeks. The primary outcome was the clinical feature of change in kidney deficiency for aging evaluation scale (CFCKD-AES) and tilburg frailty indicator (TFI). The secondary outcomes were SF-36, serum sex hormone level, five times sit-to-stand time (FTSST), 6MWT, motor function test-grip strength, balance test, walking speed, muscle mass measurement, telomerase and telomere length.RESULTSAfter 12 weeks of treatment, the CFCKD-AES and TFI scores in the BZBS group decreased by 13.79 and 1.50 respectively (6.42 and 0.58 in the placebo group, respectively); The SF-36 in the BZBS group increased by 98.38 (23.79 in the placebo group). The FTSST, motor function test grip strength, balance test, walking speed, and muscle mass in the elderly subgroup were all improved in the BZBS group. The telomerase content in the BZBS group increased by 150.04 ng/ml compared to the placebo group. The fever led one patient in the placebo group to discontinue the trial. One patient in the placebo group withdrew from the trial due to pregnancy. None of the serious AEs led to treatment discontinuation, and 3 AEs (1.14%) were assessed as related to BZBS by the primary investigator.CONCLUSIONSBZBS can improve premature aging symptoms, frailty scores, and quality of life, as well as improve FTSST, motor function: grip strength, balance test, walking speed, and muscle mass in elderly subgroups of patients, and enhance telomerase activity, but it is not significantly associated with increasing telomere length which is important for healthy aging.TRIAL REGISTRYhttps://www.chictr.org.cn/showproj.html?proj=166181.