A new method for estimating biological age (BA) on the Bio-age scale, which reflects the degree of its correspondence with respect to calendar age (CA), is presented. Anthropometric (body weight, systolic blood pressure, vital capacity, dynamometry of the right hand), biochemical (glucose and sugar levels in the blood) parameters were analyzed; body composition (percentage of active cell mass (ACM%), body fat mass (BFM%), total water (TW%), basal metabolism) in 972 people (427 men and 545 women) aged 18–70 years. An increase with age in the number of surveyed (especially among men) with BA CA was revealed. It was determined that an increase in the values of BFM%, a decrease in ACM% and TW% leads to an acceleration of the aging of the body. Dynamics of indicators of body components at the age stage of 18–70 years is characterized by a decrease in the values of ACM%, TW% and an increase in BFM%, and in the groups BA CA the negative dynamics is 2–3 times more intense. It is likely that the imbalance in the ratio of body components causes the development of numerous morphofunctional disorders. Therefore, in order to slow down the rate of aging of the organism, it is necessary to normalize the component composition of the body.