Synthroid, Armour Thyroid, and the battle for T3

In the last Heart Scan Blog post on thyroid issues, Is normal TSH too high?, the provocative findings of the the HUNT Study were discussed. The text of the study can be found at:

The association between TSH within the reference range and serum lipid concentrations in a population-based study. The HUNT Study

Hypothyroidism, or low thyroid that is signaled by high thyroid-stimulating hormone, TSH, is proving far more prevalent an issue than previously thought. While previous estimates put hypothyroidism as affecting only about 3% of younger populations, 10-20% of older populations (women more so), data like the HUNT Study suggest that, if lower and lower TSH levels (higher thyroid) are necessary for perfect heart health, then many more people stand to benefit than we used to think.

But another crucial issue in the world of hypothyroidism: Is T4 (thyroxine) enough? Or should we be supplementing T3 (triiodothyronine) along with T4?

Your friendly neighborhood primary care doctor or endocrinologist would likely argue vehemently that T4 (as Synthroid, Levoxyl, levothyroxine, and others) is adequate and not subject to the impurities and contaminants of natural thyroid extracts. They would also argue that T4 is effectively converted to T3 at the tissue level, and exogenous supplementation is unnecessary.

Others--most of all thyroid patients themselves, along with thyroid advocates like Mary Shomon and Janie Bowthorpe, along with some physicians--argue that supplementing T3 along with T4 can be very important. They argue that people feel better, have more physical energy, lose weight more effectively, and more completely resolve many of the phenomena of hypothryoidism with T3 added. There are also some data that argue the same.

Adding T3 to the mix may address the presumed poor conversion of T4 to T3 that is peculiar to some people. It may overcome the "reverse T3" phenomenon, the production of a useless look-alike T3 that occurs in some people. It may also (anecdotally) exert greater effects on some lipid/lipoprotein parameters, such as Lp(a).

My experiences adding T3 to T4 have been mixed: Some feel better, others do not. Some show objective improvements, others do not.

Nonetheless, hypothyroidism, or incompletely corrected hypothryoidism by way of inadequate T3, is an issue to consider in your plaque-control program.

More on this somewhat complex issue, along with practical solutions to consider, can be found on the Special Report to be released this week on the Track Your Plaque website.

Comments (2) -

  • Anonymous

    7/6/2008 7:51:00 PM |

    This is what I hate about medicine: one size fits all. Thyroid treatment should be based on symptom relief using labwork to make sure there isn't overtreatment. And all thyroid supplements should be available to the patient. Not just what the doctor gets paid (oops!) to use.

  • Anonymous

    7/7/2008 5:15:00 PM |

    Hi Dr. Davis,

    Check this link out...  The doctor at the link references your work.  Not sure if you're familiar with his.

    I've saved the link on two lines that need to be combined to paste into the browser.

    The interesting thing about the article for me was this...

    I have previously noticed about 1/3 of my eyebrows had gotten thinner.  And I also have wondered about the puffiness around my eyelids.


    What do you think about that site?  If you don't answer here in comments perhaps you could address in your Special Report or at your blog?

    Thanks for all you do.