My doctor switched my thyroid medicine from Nature throid grain and half to Synthroid 150 mcg.

[rjerome812]

My t3 was high and I was starting to gain weight. The doctor thought my I should try Synthoid. Anyone have experience switching and how did you feel about synthroid?

[shaws Administrator]

Did you allow a gap of 24 hours between your last dose of thyroid hormones and the test? If not your results could be skewed.

As you were taking NDT (Naturethroid) it contains all of the hormones a healthy thyroid gland would do i.e. T4, T3, T2, T1 and calcitonin. Therefore blood test results (only introduced for T4 = levothyroxine) wont correlate. It should be how the patient 'feels' on a particular dose.

A high T3 wouldn't cause weight gain. (I also think (and am not medically qualified) that the T3 would be higher as it would be converted from T4 into T3 plus the T3 in NDT. Hypothyroidism can raise our weight because we're not on a sufficient dose to enable our metabolism to rise.

Synthroid is also known as T4. T4 is an inactive hormone and has to convert to T3 (the active hormone required by the millions of T3 receptor cells in our bodies). Synthroid can work well for many who're hypothyroid.

Liothyronine also known as T3 is the Active Thyroid Hormone and it is T3 which drives our metabolism and brain and heart have the most T3 receptor cells. All T3 receptor cells need T3 for us to function as normal.

[shaws Administrator]

This is the method we advise (and am not medically qualified) is to have a the very earliest blood draw, fasting (you can drink water) and allow a gap of 24 hours between last dose and test and take afterwards. Always get a print-out of your results, with the ranges for your own records and post if you have a query.