DEAR PHARMACIST

It matters how thyroid hormone is measured


Published: Tuesday, December 4, 2012 at 3:50 p.m.
Last Modified: Tuesday, December 4, 2012 at 3:50 p.m.

Q: I went through your timeline on facebook, and learned why I'm still tired and overweight. My physician says my thyroid stimulating hormone is normal. Can you discuss hypothyroidism in your column?

— G.O., Decatur, Ill.

A: There's an epidemic of tired, overweight folks who don't know they're hypothyroid because of improper testing. Some old-school physicians are still drawing blood levels of TSH (thyroid stimulating hormone) as the sole method to evaluate thyroid function.

TSH is incapable of telling you or your doctor what's happening inside your cells. It's fine to check as part of a comprehensive profile, but not by itself. People are often told they have "normal" thyroid levels, based upon their "normal" TSH. TSH is a brain hormone and has nothing to do with intracellular (mitochondrial) levels of active thyroid hormone called T3.

You see, TSH may very well be normal, while T3, (the hormone you want) is desperately low. You will hold on to weight, have dry skin, suffer with hair loss, fatigue, muscle aches, arrhythmias, depression, forgetfulness, anxiety and low libido. Regardless of your misery, you may still be told you are OK, because your TSH is okay. Big mistake.

TSH is just a messenger hormone. It's not active, although levels are ideally around 0.1 to 1.0 mIU/l. People who feel fantastic have adequate levels of T3 inside their cells. Measuring a "free T3" gives you relevant, usable data. I'd shoot for 3.5 to 4.2 pg/ml myself.

During the same blood test, you also should measure T4 (which is inactive hormone, but it converts to T3). This is important to ascertain because it gives you a gauge to see how much hormone is available to eventually become active.

Evaluating blood levels of reverse T3 also called "reverse thyronine" and abbreviated as "rT3" is equally important. Reverse T3 is a mirror image of active T3. Elevated rT3 causes all the symptoms of clinical hypothyroidism I just mentioned. It's often high in people with heavy metals.

I lecture around the world, and still meet physicians who dismiss rT3. Did you know that hypothyroidism is a major cause for diabetes? When rT3 is high, that means it's poised like a pitbull on your cells' receptor sites preventing the real deal (T3) from entering the cell.

The net result of elevated rT3 is you feel like a zombie. But again, if your TSH is normal, or your rT3 is never measured, you will be dismissed as normal.

I prefer natural desiccated thyroid (NDT) for medication treatment, such as Nature-Throid, and Armour over levothyroxine (Synthroid). My rationale is that NDT drugs contain both T3 and T4. Remember, T3 is what you ultimately want. Synthroid is exclusively T4, so your body has to convert it to T3 before you can use it.

Unfortunately, people with metabolic issues, or digestive problems can't convert T4 well. Your physician can also prescribe plain T3 compounded, if that is more appropriate for your individual case.

For more information, visit DearPharmacist.com.

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