There are many natural treatment options for thyroid, including nutritional therapy with amino acids such as L-tyrosine, however to ensure effectiveness and long-term success, it is important to engage in treatment under the supervision of a naturopathic doctor.
Here is another similar question: http://www.wyldeabouthealth.com/questions/view/515
And here is some further info about L-tyrosine: http://www.wyldeabouthealth.com/healthnotes/us/assets/nutritional-supplement/l-tyrosine/uses
A naturopathic doctor will look at your unique case and determine the root causes contributing to thyroid imbalance. It is by addressing these factors as well as supporting the inherent healing ability of the body that you will see the best long-term results. You may be able to reduce or eliminate thyroid medication as well as improve your overall health and prevent future illness.
In my practice, I treat a lot of thyroid issues and I offer a program called Thyroid Therapy to guide treatment: http://www.wavelengthwellness.com/programs/thyroid.html
Kate Whimster, BCom, MIFHI, ND