比較含等量異黃酮（daidzein和genistein）之複方草藥「左歸丸」與單方草藥，及雌激素助孕酮療法對骨頭新陳代謝的作用。共100位婦女完成實驗，其中33位在A組，為服用單方草藥，另30位在B組，服用左歸丸，以及其他37位在c組，為使用雌激素助孕酮療法。在服用草藥的兩組，其血清中daidzein濃度在治療之後6個月顯著增加（在A組上升224%和B組上升234%，兩者p均< 0.01）。不過，血清中genistein濃度改變則不顯著。在c組，兩種異黃酮均沒有增加。骨形成指標（血清中骨特異鹼性磷酸酶[BSAP]）在B組治療6個月後顯著增加，但在A組則是稍微增加（分別為上升25.4%與15.9%，其p為< 0.01和=0.09），且此與血清中daidzein和genistein增加有關（其相關係數ß = 0.498和0.248，p分別為< 0.01和= 0.03）。骨吸收指標（尿中deoxypyridinolines/creatinine [Dpd/cr]）在服用草藥的兩組，在起始和治療之後是差不多相同。相反地，BSAP和Dpd/cr在c組治療3和6個月後則顯著減少（BSAP：降低了10.4%和30.3%；Dpd/cr：降低了21.7%和43.8%，全部p在配對t-試驗裡均< 0.01）。因此我們認為左歸丸可刺激骨頭形成，和主要抑制骨質吸收的雌激素助孕酮療法作用不同。這種作用看起來和在草藥裡的異黃酮數量有關。且與服用包含等量異黃酮的單方草藥相比較，在服用左歸丸的婦女身上此作用較強，這表示左歸丸中其他非異黃酮組成部分有協同或加成的效應。

The effects of the mixed herbal preparation “Tzuo-Kuai-Wuan” (TKW) on bone metabolism were compared with a single herb containing equivalent amounts of isoflavones, daidzein and genistein, and a combined estrogen-progesterone therapy (EPT). One hundred women completed the trial, 33 in group A, consuming a single herb, 30 in group B, consuming TKW, and 37 in group C , receiving EPT. In both herbal groups, the serum levels of daidzein significantly increased after treatment for 6 months (224% in group A and 234% in group B, both p < 0.01), though the serum levels of genistein did not change significantly. In group C , serum levels of either isoflavone changed only slightly. After 6 months of treatment, the bone formation marker (bone specific alkaline phosphatase [BSAP]) significantly increased in group B, but not in group A (25.4% vs. 15.9%, p < 0.01 and p = 0.09, respectively). The elevation of BSAP was related to increased serum daidzein and genistein (ß = 0.498 and 0.248, p < 0.01 and p = 0.03, respectively). The bone resorption marker (urinary deoxypyridinolines/creatinine [Dpd/Cr]) was nearly the same at beginning of the study and after treatment in both herbal groups. In contrast, BSAP and Dpd/Cr significantly decreased after 3 and 6 months of treatment in group C (BSAP: 10.4% and 30.3%; Dpd/Cr: 21.7% and 43.8%, all p < 0.01 in paired t-tests). Thus, we conclude that TKW stimulates bone formation, in contrast to EPT which primarily inhibits resorption This effect appears to be related to the amount of isoflavones. Further, the stronger effect in women consuming TKW than consuming a single herb that contains equivalent amounts of isoflavones suggests higher synergistic or additive effect of other components thanisoflavones in TKW.