how many percent of water in human body
1 On average, body water can account for 50% of the total human body weight and it is significantly higher in newborns. Obesity decreases the percentage of water in the body.  Body water is regulated by hormones, including anti-diuretic hormone (ADH), aldosterone and a trial natriuretic peptide.
In a newborn infant, this may be as high as 79 percent of the body weight, but it progressively decreases from birth to old age, most of the decrease occurring during the first 10 years of life. Also, obesity decreases the percentage of water in the body, sometimes to as low as 45 percent.