Fig. 2From: Dynamic alteration of serum testosterone with aging: a cross-sectional study from Shanghai, ChinaFree testosterone index (FTI) and testosterone secretion index (TSI) with aging. FTI and TSI were calculated as described in the method and presented in Panel a and Panel b, respectively. Vertical axes: mean and 95Â % CI; horizontal axis: age groups by 5-year apartBack to article page