The T4 level, because it is low whether symptoms are present or not, may inadvertently suggest the need for higher dosage of desiccated thyroid in patients who have already received adequate replacement.
Author argues that the T4 shows patient needs increased desiccated thyroid dose even though T3 is already too high
Thyrotoxic symptoms occurred in six patients and diminished or disappeared after the change to sodium L-thyroxine, suggesting that the raised T3 level with thyroid may have undesirable effects in some patients
Risk of thyrotoxic symptoms with desiccated thyroid compared to levothyroxine
thyroid, abnormally high triiodothyronine (T3) levels were seen in 36 of 38 patients receiving doses of 90 to 240 mg; compared to sodium L-thyroxine, 0.15 to 0.2 mg, the serum T3 was higher (289 +/- 15 ng/dl versus 176 +/- 9 ng/dl, p less than 0.0005) and the thyroxine (T4) lower
desiccated thyroid was more likely to cause elevated T3 while causing lower T4 levels than levothyroxine
TE therapy did not result in a significant improvement in quality of life; however, DTE caused modest weight loss and nearly half (48.6%) of the study patients expressed preference for DTE over L-T₄. DTE therapy may be relevant for some hypothyroid patients.
No officially improved QoL but modest weight loss observed - likely due to greater presence of T3 hormone, which is more active
In the subgroup analyses, those patients who preferred DTE lost 4 lb during the DTE treatment, and their subjective symptoms were significantly better while taking DTE as measured by the general health questionnaire-12 and thyroid symptom questionnaire
Why patients preferred the desiccated thyroid - but note this was a randomized, double-blind, crossover study
bugleweed, red yeast, kelp, calcium, iron, and bone meal
interact with TH absorption
Moreover, use of thyroid extract should not be contemplated during pregnancy.
NO desiccated thyroid during pregnancy
However, the long-term therapeutic efficacy of the T4:T3 ratio found in porcine desiccated thyroid and of the remaining components of porcine thyroids found in these tablets has not been assessed, leaving the direct benefits and risks of desiccated thyroid therapy untested
Lack of official testing for safety of desiccated thyroid
minimal weight loss associated with its use,
The American Thyroid Association mentions otherwise, so which is it?
There are two main clinical concerns with the use of desiccated thyroid preparations, both of which center on their T3 component. The ratio of T4 to T3 in desiccated thyroid preparations is 4.2:1, which is significantly lower than the 14:1 ratio of secretion by the human thyroid gland. This relative excess of T3 leads to supraphysiologic levels of T3 (474–477). In addition, due to the shorter half-life of T3, fluctuations of T3 occur over the course of the day, with peak levels shortly after dosing (475,477). Thus, there is concern for thyrotoxicosis if thyroid extract therapy is not adjusted according to the serum TSH.
Higher T3 presence in desiccated thyroid vs normal physiology. Additionally T3 has a short half life, so there is higher risk of thyrotoxicosis.
bioavailability of the T4 and T3 components has been shown to be the same between desiccated thyroid and synthetic preparations
same bioavailability between desiccated thyroid and synthroid
desiccated thyroid is “the cleaned, dried, and powdered thyroid gland previously deprived of connective tissue and fat
desiccated thyroid is basically the crushed up thyroid gland from an animal
Three factors were likely responsible for LT4 becoming the predominant therapy in the latter half of the 20th century: first, the isolation of T4 in 1927 by Kendall (31); second, the synthesis of T4 (32) and its better-absorbed sodium salt by Chalmers et al. (33); and third, the demonstration that the biologically active T3 was generated from T4 in humans (10).
Three factors leading to LT4 becoming the predominant choice of therapy in hypothyroidism
Desiccated thyroid extract was widely used as replacement therapy until synthetic, human identical levothyroxine became available, allowing replacement therapy to more closely replicate what happens in vivo. Desiccated thyroid comes from animal thyroid, may not provide reliable dosing and presents no clear therapeutic advantage. If using due to patient preference, TSH remains the best indicator of adequate replacement.
per CPS, no specific benefit for using desiccated thyroid over synthetic. They argue that desiccated thyroid is less reliable regarding dosing
Conversion TableDose of Thyroglobulin(grain)EquivalentsmgDose ofDesiccatedThyroid(grain)Dose of T4(levothyroxine)mgDose of T3(liothyronine)μg0.5 32 0.5 0.05 12.51 65 1 0.1 252 130 2 0.2 503 200 3 0.3 754 260 4 0.4 1005 325 5 0.5 125AVAILABILITY OF DOSAGE FORMSEach off-white to light amber-colored tablet, embossed “ECI 30”, “ECI 60” or “ECI 125” on oneside, contains: 30 mg, 60 mg or 125 mg of desiccated thyroid containing lactose, derived fromporcine thyroid glands. Nonmedicinal ingredients: cornstarch, magnesium stearate, sugar andtalc. Energy: 1.2 kJ (0.28 kcal)/30 mg tablet; 1.1 kJ (0.26 kcal)/60 mg tablet; 2.2 kJ (0.52kcal)/125 mg tablet. Gluten-, , paraben-, sulfite- and tartrazine-free. Bottles of 100 and 500tablets. Store at room temperature 15 to 30°C.
Conversion table available in thyroid (dessicated thyroid) monograph for the commercially available products. Compounding pharmacies can prepare custom dosing for your specific needs
no differences in thyroid function blood test and psychometric test results, although use of desiccated thyroid extract was associated with some weight loss
Still, there was no difference in thyroid function blood test and psychometric test (for cognitive functioning) results
The researchers report that 49% of the patients preferred desiccated thyroid extract, 19% preferred levothyroxine and 23% had no preference. Desiccated thyroid extract use was also associated with more weight loss
Results for the study appear to show benefit for dessicated thyroid compared to synthroid, both for patient preference and for extent of weight loss
some patients who continue to have symptoms of hypothyroidism when taking levothyroxine report improvement in these symptoms when switched to desiccated thyroid extract
Some people get a better response with desiccated thyroid than with synthroid
desiccated animal thyroid extract was the only treatment for hypothyroidism
So desiccated thyroid was before synthroid