Historically, most of what has been available in terms of hormone replacement (including most common form of birth control) is synthetic. More specifically, Synthetic hormones are constructed in a laboratory and not derived from nature. unfortunately, many synthetic hormones can be toxic because some cannot be broken down by the body effectively. When the body is unable to break down synthetic hormones, the “build-up” effect can lead to adverse effect. Bioidentical Hormones are plant-derived and are structurally identical to the hormones the body produces naturally.