Women experience between 50 and 75 percent more adverse drug reactions than men do. In a new study published in the journal Nature Communications, researchers looked for the specific reasons that women are more likely to suffer the negative side effects of many medications. They found a number of different factors, more than just the differences in body weight between men and women. Some of the factors that made women more susceptible included body temperature, iron levels, lean body mass, fat levels, and heart rate variability. Rather than just adjusting the doses of medications by body weight, the researchers argue that each drug should be studied individually in women to determine the potential side effects and whether they can be taken safely.