Over 20 years ago endocrinologists had experience with hormone compound pills containing both T4 and T3. Those physicians who
had the opportunity to use these compounds know that patients frequently seem to do better with them than with the more traditional
T4 (Synthroid, L-thyroxine, Levoxyl etc.). For various reasons most companies stopped producing combination thyroid hormone pills
two decades ago.
Why does combination therapy with T4 and T3 appear to provide more benefits than either hormone alone? The reason was clarified in an article published in
The New England Journal of Medicine summarized in this news report;
NEW YORK, Feb 10 (Reuters Health) -- Patients with
hypothyroidism show greater improvements in mood and brain
function if they receive treatment with two types of thyroid
hormones instead of one, according to a report in the
February 11th issue of The New England Journal of Medicine.
Hypothyroidism, where the gland has ceased to function or has been
removed, is usually treated with daily doses of thyroxine
hormone. But the researchers found that substituting another
thyroid hormone, triiodothyronine, for some of the thyroxine
dose led to improvements in mood and in neuropsychological
functioning.
"There are two thyroid hormones, thyroxine and
triiodothyronine," Dr. Robertas Bunevicius, of Kaunas Medical
University in Lithuania, and colleagues explain in their paper.
"Not all tissues that need thyroid hormone are equally able to
convert thyroxine to triiodothyronine, the active form of the
hormone," the researchers write. "Nevertheless, most patients
with hypothyroidism (reduced thyroid function) are treated only
with thyroxine."
To determine whether patients would benefit from receiving
triiodothyronine as well, Bunevicius' team studied 31 women and
2 men who lacked a functioning thyroid and were dependent on
thyroxine.
The research team divided the study into two 5-week sessions.
During one session, each patient took his or her usual dose of
thyroxine. During the other session, the researchers replaced
50 micrograms (mcg) of the thyroxine dose with 12.5 mcg of
triiodothyronine.
On 6 of 17 measures of mood and cognition -- a catchall term
that refers to language, learning and memory -- the patients
scored better after receiving thyroxine plus triiodothyronine
than after receiving thyroxine monotherapy.
No score was better after monotherapy than after combination
treatment, the study group determined. The authors also
detected biochemical evidence that "thyroid hormone action was
greater after treatment with thyroxine plus triiodothyronine."
But in an editorial, Dr. Anthony D. Toft, of the Royal
Infirmary, Edinburgh, Scotland, recommends that physicians
should not use thyroxine and triiodothyronine in combination
until the study findings are confirmed by additional research.
Toft notes that "most, if not all, of the currently available
combined preparations of thyroid hormones contain an excess
of triiodothyronine as compared with thyroxine." Besides, he
argues, the majority of patients taking thyroxine "have no
complaints about their medication."
SOURCE: The New England Journal of Medicine 1999;340:424-429,
469-470.
I have used Cytomel (T3) in treating hypothyroidism for over 18 years and
I am still surprised and gratified at just how well it works. For those complaining of persistent fatigue, muscle pain, constipation,
or weight gain, despite blood tests showing normal levels of thyroid hormone, combining T3 with T4 therapy appears to boost the
thyroid hormone action. Combining the two hormones can actually avoid the sometimes frankly negative aspects of simply increasing
the level of T4. If you or someone you know has similar problems with thyroid hormone replacement I suggest consulting with an
expert health care professional such as an endocrinologist about adding T3 supplementation.
