During the past 5 years, ABL investigates guanidinoacetic acid (GAA) role in energy metabolism. GAA is a fundamental intermediate in creatine byosynthesis, with circulating levels of GAA often reflects disturbances in its conversion due to many intrinsic and extrinsic factors in both health and disease. In our new paper, published in journal Physiological Research few days ago, we evaluated changes in serum GAA among healthy women aged 18 to 65 years. It appears that age significantly predicts serum GAA concentrations, thus perhaps nominating serum GAA as a novel gender-specific proxy of impaired bioenergetics with aging. The full text of this interesting paper is available here.