Synthroid is a stereo synthetic molecule that mimics the real thyroid
molecule. Because it is similar in the type of bonds but not the true thyroid
molecule (like Armour) the body is initially fooled into believing (metabolically) that it is getting a new, adequate dose of what it needs. The body, however, doesn't accommodate the stereo mimicry (being "fooled" by a look-alike molecule) very long and responds with symptoms similar to chemical poisoning (e.g.