A common criticism from some physicians is that natural desiccated thyroid (NDT) is "less stable than levothyroxine drugs." This criticism has been countered by the clinical experience of hundreds of thousands of thyroid patients taking NDT and their practitioners.
Now, a study published in the September 2020 issue of the Annals of Family Medicine adds to the evidence that busts this common myth about NDT. The researchers compared patients taking levothyroxine and natural desiccated thyroid drugs, over a three-year period. Matching patients for age, gender, and race/ethnicity, the researchers' findings were surprising to mainstream physicians: there was NO difference in the patients' TSH stability, whether taking NDT or synthetic levothyroxine.
A few other interesting findings:
The patients taking natural desiccated thyroid had a lower body mass index on average. This is consistent with previous studies that have found that patients who take natural desiccated thyroid lose more weight than patients on levothyroxine.
The patients taking natural desiccated thyroid a lower hemoglobin A1c level -- a measurement of average blood sugar levels. Elevated hemoglobin A1c levels are associated with increased risk of type 2 diabetes, a condition that more common in people with hypothyroidism.
According to the study authors: "This study adds to the limited body of evidence regarding the stability of levothyroxine and desiccated thyroid. A previous study noted that TSH levels remained within reference range for 12 weeks in patients treated with either levothyroxine or desiccated thyroid.5 This study showed that after 3 years, TSH values in both groups remained within reference ranges approximately 80% of the time."
The study authors concluded by stating something that patients and thyroid-savvy practitioners have been saying for decades: "The one-size-fits-all approach for treating hypothyroidism does not work...for all patients."