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Low Thyroid Function

"If everyone is thinking alike then somebody isn't thinking."

George S. Patton 

The Most Common Malady! The Shame Of Conventional Medicine!

Although growth hormone (hGH) is the hormone most associated in the public mind with anti-aging medicine, thyroid, by far, engenders the most interest from patients. As well, the anti-aging doctor’s use of thyroid replacement therapy causes the greatest anger from the rest of the medical establishment, especially from other doctors and pharmacists. I guarantee to you that this antipathy arises solely from the twin demons of ignorance and arrogance.

Hypothyroidism is poorly diagnosed and treated by conventional medicine. For this reason, once it gets around that the anti-aging doctor will actually treat low thyroid function with thyroid, and actually to the extent that low thyroid symptoms are completely reversed, patients flock to the anti-aging doctor for relief!

Once hypothyroid patients feel the difference between using true thyroid replacement and the conventional crap, they will no longer tolerate the conventional propaganda. Such patients even recognize and rebel against the scare tactics drummed into the heads of doctors in medical school.

When patients tell conventional practitioners of the benefits of using thyroid replacement therapy, the response is invariably denial and anger.

“The experts in a particular field can become so indoctrinated and so committed to the current paradigm that their critical and imaginative powers are inhibited, and they cannot ‘see beyond their own noses.’” [1]

The problem posed by these patients to the anti-aging doctor is that, in the main, these patients are not interested in compliance with guidelines concerning exercise, nutrition, and other hormone supplementation. These patients are not anti-agers. They are driven solely by the desire to remain escaped from the misery and stupor of hypothyroidism.

What Is Thyroid Hormone, And What Does It Do?

The thyroid gland normally weighs only an ounce or so and is situated at the base of the throat. It manufactures an inactive form of the thyroid hormone, T4 (also known as Thyroxine or Levothyroxine), and extrudes it into the blood. Thyroxine then acts as a reservoir for conversion into the active form of the thyroid hormone, T3 (also known as Triiodothyronine). T3 performs all of the wonderful attributes of thyroid function:
T3 regulates the rate at which calories are burned, or metabolic rate, thus contributes powerfully to a person’s sense of energy and warmth.T3 in promotes protein synthesis. As well, it increases fat breakdown. It lowers the “bad cholesterol” or LDL. It improves thinking and memory.
Why Do I Say: “Low Thyroid Function” and not “Hypothyroidism”?Actually, I may use “hypothyroidism” a time or two. It is OK to use it. But be aware that this term can have specific definitions applied to it by medical or insurance organizations. So, I usually use “low thyroid function” or “T3 deficiency”, referring to the active form of the thyroid hormone. 

Illustration

What Are The Causes Of Low Thyroid Function?

The common causes of low thyroid function are low production of T4 in the thyroid gland, low conversion of T4 into T3, and inadequate response of the thyroid receptor sites to stimulation by T3.

Thyroid function declines with age. Low thyroid function commonly occurs in women after childbirth or other physical trauma. It is seen during and after great psychological trauma. Low thyroid function is the invariable end result of hyperthyroidism (excessive production of thyroid hormone). 

What Are The Symptoms And Consequences Of Low Thyroid Function?

The symptoms of low thyroid function are many. Some, like generalized hair loss in women, diminished sweating, and cold hands & feet are highly associated with low thyroid function. Others, like depression and weight gain, are general symptoms which can be the result of any number of causes. However, when taken as a constellation, a pattern emerges which is very telling.

The following is an incomplete list of symptoms related to low thyroid function:

● fatigue (or low energy)● weight gain with difficulty dropping weight● low temperature (normal body temperature is typically 98.6 degrees Fahrenheit)● feeling cold a lot● cold hands & feet● sensitivity to stress● depression● postpartum depression● anxiety● panic attacks● irritability● fragile emotions● teary over minor stimuli that strikes emotion (as while watching some dumb commercial on TV)● decline of cognition: short term memory loss & poor concentration;● “brain fog” is a term that resonates with hypothyroids● hair loss in women● loss of lateral eyebrows● brittle, flaking fingernails

● dry skin &/or dry patches of skin● coarse skin● numbness & tingling in extremities,● especially waking up in the night with numb tingling arms & hands● puffy eyes (“bags”)● eyelid edema● diminished sweating● muscle & joint pain● persistent low back pain● fibromyalgia● constipation (or constipation alternating with loose bowel movements)● sleeplessness● slow pulse rate● elevated cholesterol● difficulty swallowing● throat pain● hoarseness● Any number of these symptoms may appear in a person suffering from inadequate thyroid hormone.

Thyroid hormone has a powerful controlling effect upon other hormones, most notably progesterone. Thus, with low thyroid function we commonly see:

● infertility● miscarriages● mood swings● PMS: irritability, bloat, swelling, uterine cramping, food cravings​● irregular menstruation● heavy menstrual flow, especially during day 1 and day 2● powerful uterine cramping during the first several days of menstruation

What are other consequences of low thyroid function? Besides the continuation of the above listed symptoms:

● acceleration of heart disease● arteriosclerosis (calcific plaque laid down on the insides of arteries)● hypertension (elevation of blood pressure)● cognitive decline

The great frustration of low thyroid patients

​Low thyroid function has been estimated to afflict 9.5 % of the population.2 We anti-agers know that given age-related decline of hormone production, low thyroid function eventually affects everyone living long enough.

So, proper diagnosis and treatment of this malady is no small issue, whether we are talking about personal misery or the perspective of the loss of productivity to society.

What follows is a short description of the current state of affairs regarding the diagnosis and treatment of low thyroid function along with its rational counterpoint. For anyone curious about the history of this area, I can give you a short version of it in the following two sentences. Concerning the guilt of medical doctors, think of arrogance on top of ignorance and an infantile devotion to authority. 

But please don’t forget the drug companies: greed and corruption.

How Is Low Thyroid Function Diagnosed? Competing Points Of View

First, the conventional way......


Conventional medicine views the diagnosis of low thyroid function to be a simple matter of looking at the blood level of one hormone associated with thyroid function, the TSH or Thyroid Stimulating Hormone. The vast majority of medical doctors of all specialties except endocrinology are taught that measuring the blood level of this brain hormone is all that is necessary to obtain the diagnosis of low thyroid function. If the patient appears to have some complexity falling outside of this paradigm, then referral to an endocrinologist is in order. And actually, endocrinologists generally adhere to this simplicity as well, but act as the court of final appeal, the ultimate authority. If the endocrinologist says that you don’t have low thyroid function, then, by golly, you don’t have it. And this Supreme Court decision is almost always based upon on a simple blood test, the TSH.

So, What Is The TSH?

First of all, it is NOT a thyroid hormone! The TSH is the hormone that sends messages from the brain to the thyroid gland. If the brain perceives a lack of thyroid hormone, then the production of TSH can increase, resulting in a measurable increase in the blood. Such an event demonstrates the brain’s demand upon the thyroid gland to increase production. If the TSH decreases, then the brain is signaling the thyroid gland to decrease production.

Does this relationship always pertain? Nope! Too much complexity is involved. Patients with an elevated TSH can be said with certainty to have low thyroid function. However, those with “normal” or low TSH levels can have low thyroid function as well!

The problem is that medical students of the last two or three generations have been taught, by rote, that this brain hormone, the TSH, is an absolutely perfect reflection of thyroid function! What is the scientific basis of this robotic relationship? None! It is just an opinion. It is just an opinion that garners acceptance by virtue of repetition by those considered elevated in the field.

Bizarrely, the TSH is given such mystical powers that great efforts have been made to increase the accuracy of the TSH down to the 10-thousandths place, thus, somehow giving us a more scientific diagnosis!

I am not aware of any instance in which the “ultra-sensitive” measurement of the TSH has done anything more to benefit a patient.

What is the “range” shown on a blood studies report?

Before we leave the subject of the TSH, we need to look at the issue of “normal”, “reference range”, and “reference interval”.
I can’t tell you how many patients have come to me with the story that the diagnosis of their low thyroid state has been stymied by being just within the “range”. If the TSH had been just a tad higher, then the diagnosis would have been bestowed, and treatment would have been offered.

But, since the TSH was a teeny bit within the “range”...... sorry, you have to live in a stupor the rest of your life!

Amazing! Don’t tell me that doctors aren’t stupid!

What is the “range” shown on a blood studies report?

Laboratories are required by regulation to provide a “range”. They’re not required to provide a normal range, and certainly not an optimal range, but only a “range”.

I have been told by pathologists (MD’s specializing in tissue diagnosis) working for laboratories that the “range” is a statistical spread of pooled results from patients in whom the blood study in question has been measured. So, what we may be looking at is 1 or 2 standard deviations below the mean to the same above the mean concerning patients in whom the doctor is concerned about pathology. Now, understand, we are not talking about the football team here. We are talking about the “range” seen in the weak and sick!

Such would be the case if the statistical analysis concept were true.

Looking further at this issue, I noticed that the top number and the bottom numbers of various ranges tend to be nice, round numbers. Continuing discussions at medical conferences have brought me to the understanding that many of these range endpoints are entirely arbitrary as in the case of cholecalciferol (natural “vitamin” D) or even politically correct as is seen in the “range” for fasting blood sugar.

Since laboratories are required to state a “range”, they state one. But, they don’t state the basis of the “range”. So they let you, the patient, or the dummy doctor, assume that the range means “normal”. Thus, to further obfuscate things, the laboratories invented various terms, like, “reference range” and “reference interval”. So, if ever called on this, the laboratory can easily say: “Gosh, we never said the range represented ‘normal’. We just wanted you to know that this is an ‘interval’ that you can ‘refer’ to.”

Another aspect of this “range” business is nonsensical. Ranges differ from laboratory to laboratory. But a measurement is absolute. Your measured TSH will be virtually the same if measured in two different laboratories, given some small, insignificant amount of variation. But one laboratory “reference interval” says that you are hypothyroid and the other says you’re not. So, which declaration should we use?

Moreover, if you have a TSH of 75, is your hypothyroidism worse that someone else with a TSH of 7.5, both of which are acknowledged by all authorities as hypothyroid? In other words, is there a relationship between the extent of the TSH and the severity (of symptoms) of hypothyroidism?

Such a relationship may exist when comparing results of one particular patient over time. However, I know of no way to compare TSH results between patients. I know of no relationship between the severity of symptoms and the extent of the TSH. You can only know if it is normal or abnormal.

I remember a patient telling me that when first presenting to another practitioner for the diagnosis of hypothyroidism, she had a TSH of 75. She was told that the doctor was amazed that she was conscious. Baloney! I am amazed that the doctor was conscious!

What is normal for a TSH?

Really, in health and in youth, you do not see a TSH greater than about 1.3 µIU/mL. Us Natural Hormone Replacement doctors typically refer to any TSH at 2 or above as abnormally elevated. That’s the short answer.

The American Association of Clinical Endocrinologists now state that 3 µIU/mL is the cutoff point between normal and abnormally elevated TSH (indicating low thyroid function) [3].

The basic problem with all of this attention to the TSH is that it distorts the significance of the TSH. Just remember, the TSH is NOT central to the diagnosis of low thyroid function. It has only peripheral significance.

In fact, the TSH has no specific or reliable correlation with thyroid function! [4] 

How Do Us Natural Hormone Replacement Doctors Diagnose Low Thyroid Function?

What is the competing method used to diagnose low thyroid function? How do us natural hormone replacement therapists, us anti-agers, do it?

Common sense works well! Blood studies are very helpful in diagnosing low thyroid function. But, for a wide variety of reasons, none of the available blood studies provide infallible diagnosis under all conditions. Low thyroid function continues to be a clinical diagnosis and blood studies are used to provide confirmation. It’s important to integrate laboratory testing into a comprehensive approach to evaluation that also includes the patient’s history, symptoms, & signs [5].

The search for the perfect laboratory diagnosis of low thyroid function continues, the main issue being how to determine thyroid function at the cellular level [4].

Sometimes, the combination of the constellation of symptoms plus the blood studies make the diagnosis perfectly clear, and sometimes ambiguity continues until a trial of thyroid supplementation makes the issue clear. One thing for sure...... only thyroid reverses hypothyroidism. Nothing else works [6].

To repeat! This is of supreme importance when the diagnosis of hypothyroidism is unsure. If the patient’s symptoms are reversed during a short trial of thyroid supplementation, then the diagnosis is clear regardless of blood study results!

What specific studies do us natural hormone replacement therapists use? We use, in order of their worth in diagnosis: the Free T3, the TSH, and the Free T4 [7]. Only the Free T3 correlates to the severity of the signs and symptoms of low thyroid function [8]. Of greatest value in diagnosis is a look at the combination of these three studies measured upon the same sample of blood. “I have found that a combination of the three blood tests delivers the most accurate information in regards to thyroid health.” [6] “We propose that if assays for thyrotropin (TSH), free T3, and free T4 are all done, knowledge of these patterns coupled with clinical details and simple additional tests allow a diagnosis to be made in almost all cases.” [9]

The word “Free”, in the instance of blood studies, indicates the fraction of the hormone that is not bound up in protein in the blood. Thus, we are obtaining an understanding of that part of the total hormone in the blood that is actually available to do its function. As stated earlier in this essay, the Free T4 is a long-lasting reservoir of hormone that upon demand, can be transformed into T3, the active form of the thyroid hormone. It is the quickly used up Free T3 that gives us energy, warmth, and quick mental function.

How Is Low Thyroid Function Treated?

Competing Points Of View: Conventional Medicine Ignores The Misery Of Hypothyroidism
So, you have run the gauntlet of diagnosis of hypothyroidism. Your practitioner acknowledges your excessive TSH, and lists your diagnosis on your receipt as the CPT code, 254.9. You are officially hypothyroid.
Now, what happens? Next, you will be given a prescription for a low dose of synthetic T4 (levothyroxine) under a variety of brand names, like Synthroid®, Levothroid®, and others. You are told to take this pill daily in the morning and come back in for another TSH test in about 6 weeks. Then, depending upon the subsequent TSH result, you may be given a higher dose of levothyroxine, and the process is repeated. Somewhere along this continuum, you may notice that you feel a little better.
What you at first imagine, is that the doctor is trying to determine the best dose based upon how you feel. Nothing could be farther from the truth. As a matter of fact, how you feel is nothing more than an irritant to the practitioner who is concentrating on your holy TSH report.
Any of you readers who have been through this lunatic process know exactly what I am talking about!
So, what is the practitioner worried about? Why doesn’t he or she just give you enough levothyroxine to make you feel good and get it over with??
Well, the answer is that the practitioner is WORRIED that you might end up with a SUPPRESSED TSH! In fact, the whole goal of therapy is NOT for you to feel better! The complete goal of conventional therapy is to regulate the TSH to be within a certain range.
So, if you are so whiney as to continue to complain about how you feel, you WILL be given an anti-depressant. That is, if you haven’t already been given one!
If that doesn’t stop you from your inconvenient agitation, then you will likely be given a second antidepressant!
Consider yourself lucky that you had a TSH of greater than 4.5. How about the poor schmuck who had a TSH of 4.4? That person got NO levothyroxine at all, but only the Prozac®, or Wellbutrin®, or Effexor®, or whatever.
Those of you who have already been through this charade know I am not joking!
In my experience, antidepressants are the drugs most commonly prescribed for low thyroid function. Synthroid® rates a distant second. And the drug companies make more if the poor patient takes the antidepressant. 
So, what’s the problem with a suppressed TSH? Beats me!
I have looked into this issue in the medical literature. I have years of experience reversing low thyroid symptoms using ....... thyroid!
And guess what? Suppression of the TSH is an expected consequence of thyroid supplementation that has no adverse health consequences!Moreover, as stated earlier, the TSH has no specific or reliable correlation with thyroid function! [4] 
The large majority of medical practitioners follow the system of prescribing synthetic levothyroxine to regulate the TSH, ........ even though this practice has no scientific foundation!

Where does levothyroxine come from? Is it thyroid?

Levothyroxine is synthetic T4, the inactive form of the thyroid hormone. It is definitely not thyroid. Thyroid material contains T4, but also T3 (the active form, remember), T2, T1, and various other substances that support the effects of the hormones themselves.

Because of the lack of supporting substances, synthetic levothyroxine is infamous for not converting into T3. And T3 is the active form. You will read that T4 has a fraction of the activity of T3, but it is unclear if this means that T4 actually stimulates the thyroid hormone receptor site or that a small fraction of it is converted into T3 which then stimulates the receptor site.

“Levothyroxine is an inherently unstable drug, markedly affected by light, heat, & humidity. Although on the market for many years, it was not officially approved by the FDA until recently.”10 (The Medical Letter, Vol 46, Issue 1192, 9/27/04) In 1997, inconsistency in the stability and potency of various formulations of Levothyroxine prompted the FDA to reclassify all oral levothyroxine products as new drugs & require New Drug Applications from the manufacturers.11 (Thyroid 2003, JV Hennessey, 13:279)

“...these products fail to maintain potency through the expiration date, and tablets of the same dosage strength from the same manufacturer vary from lot to lot in the amount of active ingredient present. This lack of stability and consistent potency has the potential to cause serious health consequences to the public.”

“SUMMARY: The Food and Drug Administration (FDA) is announcing that orally administered drug products containing levothyroxine sodium are new drugs. There is new information showing significant stability and potency problems with orally administered levothyroxine sodium products.” [12]

FDA Notice, From the Federal Register: August 14, 1997 (Volume 62, Number 157) 

Conventional Medicine Doesn’t Get It!

Dr. John C. Lowe, in his excellent book, The Metabolic Treatment of Fibromyalgia, says it well:
“When the experts can no longer see beyond their noses, the public has grounds for not believing in their science.

​In recent years, steadily growing numbers of people have expressed the belief that the experts in conventional endocrinology can’t “see beyond their noses.” Why do people express this belief about the experts? Mainly for one reason:

The experts’ beliefs about thyroid hormone treatment keep many people sick.
And these people remain sick until they undergo treatment by practitioners who don’t share the experts’ beliefs. Obviously, the expert’s beliefs are wrong. Yet despite the continuing illness of patients and their subsequent recovery under the care of other practitioners, the experts hold tenaciously to their false beliefs. It is little wonder then that patients question the credibility of conventional endocrinology “experts.” [13]

Natural Hormone Replacement Doctors Get It Right!

Doctors who practice Natural Hormone Replacement therapy, on the other hand, prescribe Thyroid USP or compounded T4T3 combinations, seeking symptom reversal without regard to the TSH and find success with great benefit for patients.
As a matter of fact when low thyroid symptoms are reversed and the patient feels the best, the TSH is ALWAYS suppressed! This is what I see 100% of the time. This is my experience. This is also the common understanding of other Natural Hormone Replacement doctors. However, endocrinologists are hard put to actually state this in the medical literature because of current prevailing opinion. Still, British endocrinologist Toft was able to state in an editorial: “Some patients achieve a sense of wellbeing only if Free T4 is slightly elevated and TSH low or undetectable.” [14] Regarding the TSH, I would replace “some” with “all”.

Conventional practitioners with tell you that suppressing the TSH will cause heart disease. But they cannot demonstrate that with any fact. It’s a myth!

Or, they say that suppressing the TSH will make your bones melt away. Again, no scientific demonstration, more myth.
So, from where do these allegations arise? Leave it to the British researchers to point out the emperor’s new clothes!

“The dangers of osteoporosis and cardiac catastrophe—particularly during a three –month trial—are sometimes quoted, but these worries are unfounded and condemn many patients to years of hypothyroidism with its pathological complications and poor quality of life.” [15]

Studies of elderly women taking levothyroxine show them to also have osteoporosis. No big surprise there! Elderly women not taking levothyroxine also have osteoporosis.

My thyroid patients undergo regular bone density studies. Those taking thyroid, plus supplementation of other hormones found deficient due to age-related decline, invariably demonstrate increase of bone density. These bone protecting or building hormones include estradiol (human estrogen), progesterone, testosterone, and DHEA.

One consequence of age- and lifestyle-related damage to the heart is atrial fibrillation (AF), or irregularly irregular heart beat. 4% of people over the age of 60 have it. By age 70, 10 % of people have AF. How does AF show up? The heart manifesting AF has damage to the electrical conduction system regulating heart beat. The damage has occurred over a number of years. But, it first shows up after some precipitating event, like hiking on a hot summer day, a scary or emotional event, or initiating various medical therapies, including thyroid replacement therapy. Did the thyroid cause the AF? No! Should we withhold thyroid supplementation therapy from patients suffering from low thyroid function just because of the possibility of precipitating AF? Not in my opinion. Should we be careful? Yes, we should at all times be careful. We should identify patients likely to have incipient AF. We should at all times monitor patients and encourage patients to report any problems that arise.

Moreover, hypothyroidism is an independent risk factor for atherosclerosis, myocardial infarction (heart attack), and acceleration of heart disease. (The Rotterdam Study)

Still, the researcher, Shapiro states: “In the absence of symptoms of thyrotoxicosis, patients treated with TSH-suppressive doses of L-T4 may be followed clinically without specific cardiac laboratory studies.” [16]

The problem that arises for the patient taking thyroid supplementation, of course, is that whenever any concurrent problem arises, whether heart related or not, the thyroid supplement will immediately be condemned. So, the anti-aging and hypothyroid patient has to be ready and willing to stand up to this ignorant abuse. 

What Is Thyroid USP?


Thyroid USP is highly processed pig thyroid. The US government publishes the recipe for producing Thyroid USP in the United States Pharmacopeia.

It is a powder produced from USDA Grade A porcine thyroid glands. They are cleaned, dried, & powdered, having been previously deprived of connective tissue & fat. They meet the USP microbial requirements for the tests {USP “61”} for absence of the bacteria Salmonella & Eschericia coli. (1995 USP 23 NF 18, pp. 2684-2685) [17]

Thyroid USP powder must yield not less than 90% & not more than 110% of the labeled amounts of levothyroxine (T4) & liothyronine (T3). (However, various commercial sources claim 2% accuracy.) Each 60 mg (1 grain) tablet of Thyroid USP contains 38 µg of T4 & 9 µg of T3. (1997 USPDI-Volume III- 17th Edition., p. IV/518)18. And you can bet on it!

So, what does this mean for the patient? Thyroid USP is a source of pure, stable, consistent T3, T4 and all supporting thyroid substances.

In my many years of experience prescribing both Thyroid USP and the synthetic forms of T4 & T3, virtually 100 % of patients who have tried both will agree that Thyroid USP is vastly superior.

Any medical practitioner who tells you that Thyroid USP is “old fashioned” or “inconsistent” is showing you his or her ignorance and lack of experience. They are only parroting sales pitches from drug companies and their paid lackeys. One of my favorite sources to quote for repeating this bullshit is the book, Thyroid For Dummies! [19] Yes, indeed!

How do I evaluate and manage low thyroid function?

Firstly, I have the patient give me a detailed medical history including a recitation of any symptoms related to low thyroid function. I order a complete set of blood studies. During our initial consultation, which may easily total 3 hours, we carefully review all current and prior blood studies, which have been detailed on a flow chart. The patient does not have to ask for copies of ordered blood studies! They are automatically provided along with copies of flow charts and a printed report that includes both discussion of the lab studies and a plan of action. The patient is encouraged to monitor often in the office (body composition analysis and vital signs). Prescriptions are written for a year but maybe revised appropriately throughout the year as conditions warrant. Blood studies are repeated for an annual review with me at which time prescriptions are again written for the following year. 
The fee is paid annually and includes all physician services. Laboratory studies are paid separately to the laboratory company. Medical insurance typically pays for laboratory studies and a fraction of the physician fee. Although I will provide receipts required for medical billing by the patient, my office does not bill insurance, including Medicare. All Medicare recipients are required to notify me of their status and sign a Medicare waiver.
Besides the initial consultation and the annual review, the patient will be seen formally in the office for follow-up evaluation as appropriate. Patients are allowed indefinite numbers of contact with the doctor either in person or telephonically by appointment. Any emergent situation regarding the patient will be given rapid attention by me.

​Bibliography:● Ziman, J.: Reliable Knowledge: An Exploration of the Grounds for Belief in Science. Cambridge, Cambridge University Press, 1978.● Canaris, GJ, et al. The Colorado Thyroid Disease Prevalence Study. Arch. Intern. Med. Vol 160, Feb 28, 2000.● AACE Medical Guidelines for Clinical Practice for the Evaluation and Treatment of Hyperthyroidism and Hypothyroidism, Endocrine Practice, Vol. 8, No. 6,● American Association of Clinical Endocrinologists (AACE), www.aace.com, Nov/Dec, 2002.● Meier, Christian, et al, Serum TSH in assessment of severity of tissue hypothyroidism in patients with overt primary thyroid failure, BMJ, vol 326:8Feb2003.● Lowe, John C., The Metabolic Treatment of Fibromyalgia, McDowell Pub Co, 2000, page 797.● Natural Hormone Replacement for Men and Women, Neal Rouzier, MD, WorldLink Medical Publishing, pg 169.● “Measurement of free hormone levels is the best indicator of thyroid function.” Handbook of Diagnostic Tests, 2nd Ed, Springhouse, 1999, pg 218.● Hamburger, J.I.: Section summary: diagnosis of thyroid function. In Diagnostic Methods in Clinical Thyroidology. Edited by J.I. Hamburger, New York, Springer-Verlag, 1989, pp. 112-123.● Dayan CM, Interpretation of thyroid function tests. Lancet. 2001 Feb 24;357(9256):619-24.● The Medical Letter, Vol 46, Issue 1192, 9/27/04.● JV Hennessey, Thyroid 2003 13:279.● FDA Notice, From the Federal Register: August 14, 1997 (Volume 62, Number 157).● Lowe, John C., The Metabolic Treatment of Fibromyalgia, McDowell Pub Co, 2000, page 986.● Thyroid function tests and hypothyroidism; Measurement of serum TSH alone may not always reflect thyroid status (editorial), Toft, A, BMJ 2003; Vol 326:295-6, 08Feb03.● Skinner, G.R.B., Thomas, R., Taylor, M., et al.: Thyroxine should be tried in clinically hypothyroid but biochemically euthyroid patients (Letter). Brit. Med. J., 314:1764, 1997.● Shapiro, L.E., Sievert, R., Ong, L., et al.: Minimal cardiac effects in asymptomatic athyreotic patients chronically treated with thyrotropin-suppressive doses of L-thyroxine. J. Clin Endocrinol. Metab., 82(8):2592-2595, 1997.● 1995 USP 23 NF 18, pp. 2684-2685.● 1997 USPDI-Volume III- 17th Edition., p. IV/518.● Thyroid For Dummies, Alan L Rubin, MD,WileyPubInc (2006), pg302.