The cleaved part of collagen during collagen formation was secreted into the circulation. The present study used this remnant part of collagen called procollagen type 1 propeptide at carboxyl terminal (PICP) as a bone formation marker. Clinical study of efficacy of hydroxyapatite tablet(800 mg) in 47 menopausal women with bone resorption marker, (CTx) below 0.330 ng/ml.and their general condition is healthy. All cases were free of medication at least one month before the present study. After one month, the mean of PICP was 1452.28 ng/ml SD=625.58 which is significantly higher than the mean of baseline control, 930.98 ng/ml SD=477.44 (p=0.0001)

Keywords: Procollagen type 1 propeptide, PICP, Hydroxyapatite