The intervention durations ranged 1 to 36 months, and the isoflavone supplement dosages were 2 to 600 milligrams per day.

Isoflavone changed markers of bone turnover as follows:

Decreased (improved) 2 of 6 bone resorption markers
- β-cross-linked C-telopeptide of type 1 collagen (−0.094 ng/mL)
- Pyridinoline (large effect size)
Altered bone mineral concentrations
- Blood calcium levels (+0.34 mg/dL)
- Blood phosphorus levels (−0.065 mg/dL)
Increased 1 of 4 bone metabolism–regulating hormones
- IGF-1 (+9.8 ng/mL)

There were no changes in 4 markers of bone formation or 3 markers of osteoclast differentiation regulators.

The risk of bias was high in 35 studies, unclear in 28 studies, and low in 10 studies.

Isoflavones for bone turnover in postmenopausal women Original paper