What are the substantive risks of T3 therapy (c22)? T3 is a molecule that is present from birth in every human’s body, and is absolutely necessary for good health. There is nothing inherently bad about the molecule-our lives depend on it. It can’t and hasn’t directly damaged the tissue of your heart, brain, or other tissues. There is not a shred of evidence that suggests that thyroid hormones, when used properly, can damage the body in any way. But T3 is not candy, and T3 therapy is not completely without risk, as nothing is. The major consideration in terms of risk is cardiovascular. Cardiovascular disease is a major problem in our country. Every day many people who are not on thyroid medicine have heart attacks, strokes, and develop arrhythmias. The whole trick to T3 therapy is keeping the T3 levels steady. Unsteady T3 levels can increase a patient’s chances of increased heart rate, and palpitations. And if a patient is already on the verge of having a heart attack or a stroke, these cardiovascular side effects could aggravate the situation (p142). In some cases it is difficult to avoid unsteady T3 levels, and so it might not be advisable to implement T3 therapy in those patients who may not have the cardiovascular reserve to tolerate unsteady T3 levels very well (for example, certain elderly patients) (Q17). T3 therapy is not addictive, and does not necessarily need to be taken for life. With proper T3 therapy, one does not expect drastic problems, because one does not make drastic changes, and any side effects are addressed early. The T3 should be taken as well on time as possible to minimize the chance of side effects (See Chapter 11).