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Importance of Thyroid — Thyroid Hormone Replacement

Importance of Thyroid — Thyroid Hormone Replacement

At JumpstartMD, we are offering a way for you to remain happy, healthy, vigorous, and vital long into the 2nd half of your life by restoring your optimal levels of targeted, natural, biologically identical hormones through bioidentical hormone replacement therapy (BHRT). We can customize treatments to your individual needs, so that you receive appropriate levels of bioidentical testosterone and / or thyroid (for men and women) and estrogen and / or progesterone (for women).

Natural thyroid can be extremely beneficial in the following two scenarios:

  • Patients with undiagnosed clinically symptomatic hypothyroidism (low thyroid disease), despite “normal” yet sub-optimal thyroid levels
  • Patients with known hypothyroidism treated with synthetic T4 (thyroxine) replacement (such as Synthroid® and Levoxyl®) who are nonetheless still clinically hypothyroid without the addition of T3 (triiodothyronine) therapy

Why Optimization of Thyroid Hormone Matters

Optimal levels of thyroid hormone are essential to your well-being because thyroid hormone meaningfully impacts every cell and organ in our body. Symptomatic hypothyroidism may thus present itself in a host of protean ways and result in symptoms often confused with menopause or attributed to age. It may, in fact, be your thyroid gland that’s aging with the following adverse side effects:

  • Depression
  • Fatigue or lethargy
  • Weight gain
  • Forgetfulness or slow thinking
  • A tendency to feel cold even when others feel warm
  • Constipation
  • Hair thinning, skin dryness and deterioration of nails
  • Menstrual irregularities
  • Abnormalities in cholesterol and triglycerides

Whether mistaken for menopause, depression, or normal aging, the key to symptomatic hypothyroidism is that it will not correct itself without addressing the root cause. Anti-depressants, reassurance that your symptoms are just a factor of age, and recommendations to lose weight with diet and exercise–none of these will suffice when what is actually needed is optimal blood levels of metabolically active T3 hormone.

What are T4, TSH, and T3?

Your thyroid gland resides in your neck and produces T4, a pro-hormone that really doesn’t become metabolically active until it is converted to T3.

Thyroid stimulating hormone (TSH) is a hormone secreted by the pituitary gland to stimulate production of T4 in the thyroid gland.

How Do Thyroid Hormones Diminish as We Age?

As we age, three things occur with your thyroid hormone:

  1. The thyroid gland produces less T4
  2. The body converts T4 to T3 less effectively
  3. The thyroid receptor becomes less sensitive to T3

As a result, clinically low and symptomatic levels of thyroid hormone can arise.

Why Do We Often Misdiagnose and Under Treat Symptomatic Low Levels of Thyroid?

To make matters worse, studies show that two factors lead to under treatment of symptomatic hypothyroidism. First, many doctors perform thyroid screening tests via laboratory evaluations of thyroid stimulating hormone (TSH).

T4 and TSH are arguably insufficient screening tests for hypothyroidism because it is T3, not its precursor, T4, that exerts a biological effect. Thus it is T3 levels that need to be optimized within the normal range. Yet all to often, physicians screen for thyroid disease with TSH testing or TSH plus T4 testing and resist further evaluation of T3 levels if TSH and T4 are within normal limits. That evaluation approach can lead to missed cases of clinical hypothyroidism:

  • “TSH is a good test to measure hypothyroidism. However, TSH is a poor measure of symptoms of metabolic severity. Therefore, it is the biological effect of thyroid hormone on the peripheral tissue, and not the TSH concentration, which reflects the clinical and metabolic effects.” British Medical Journal 2003 February; Vol. 326: 325-26

The Case for Optimization of T3 Levels:

Patients tend to both feel better and optimize their health risks more effectively when T3 levels are not simply within normal limits for age, but at the high or optimal end of normal (as would be typical of a younger person in their 20’s or 30’s):

  • “Low levels of free T3 in patients resulted in increased disability, depression, decreased cognition, energy, and increased mortality.” Journal of the American Medical Association 2004 December Vol. 292(2c): 500-04
  • “Low-normal thyroid levels result in increased cholesterol, increased heart disease, fatigue, low energy, depression, and memory loss. Thyroid replacement eliminates these risks. No study has shown any harm or adverse effect of treatment.” Consultant 2000 December: 2397-99

Nonetheless, treating to optimize T3 levels at the high end of normal via active replacement of natural T3 hormone is not commonly done, despite studies that show that patients with clinical hypothyroidism receive more benefit by supplementing with the combination of oral T4 and T3. This makes intuitive sense because it is the latter hormone that provides the metabolically active form of thyroid. Common forms of such bioidentical T3 and T4 combination therapy include Armour® thyroid or Naturethyroid ® .

In contrast, replacement of synthetic T4 (Synthroid® or Levoxyl®) alone, the most commonly prescribed form of thyroid replacement, can leave patients with normal T4 and TSH levels but sub-optimal T3 levels. That’s at least in part true because we decrease our ability to convert T4 to T3 as we age. The resulting decrease in metabolically active T3 levels is problematic because low T3 levels lead to symptomatic hypothyroidism. To optimize levels of biologically active T3, combination therapy with bio-identical forms of both T4 and T3 is thus clinically superior.

  • “Combined T4 and T3 therapy resulted in symptoms, well-being and weight loss in comparison with straight T4 therapy. A decrease in weight resulted from using higher T3 levels.” Journal of Clinical Endocrinology and Metabolism 2005 May; 90(5): 2666-74
  • “Patients that took a combination of T4 and T3 experienced better mood, energy, concentration and memory and improved well-being. Patients on just T4 experienced no change.” New England Journal of Medicine 1999 February; 340:424-9

Optimization of T3 levels matter, however, not simply so people can increase their well-being: mood, energy, cognition, improvements in hair and skin, decreased cold intolerance, and more – but because low T3 is associated with a number of significant health risks. Heart disease is one such example wherein low normal T3 levels are associated with a four-fold increased risk of heart disease, worsening of cholesterol, decreased exercise tolerance, increased stroke risk, and more:

  • “Women with low-normal thyroid levels had a four fold increased risk of heart disease. The increased risk was equal to the risk of smoking and high cholesterol. Low normal thyroid hormones are a strong predictor of heart attack.” Annals of Internal Medicine 2000; 132: 270-78
  • “Low T3 levels are associated with increased heart disease and decreased cardiac function. Replacing T3 increases clinical performance and cardiac output. Adding T3 increases exercise tolerance and quality of life.” Cardiovascular Reviews and Reports 2002 23: 20-26
  • “Decreased T3 levels result in increased cholesterol and heart disease. Treating with T3 improves the lipid profile.” Preventive Cardiology 2001; 4: 179-82
  • “We have demonstrated that carotid intima-media thickness is independently associated with thyroid function within the normal reference range, which suggests an increased cardiovascular risk in subjects with low-normal thyroid function.” Atherosclerosis 2009: 204: 77-81
  • “Thyrotropin levels (T3), even those within the reference range, were linearly associated with Coronary Heart Disease mortality in women. The results indicate that relatively low but clinically normal thyroid function may increase the risk of fatal Coronary Heart Disease.” Archives of Internal Medicine 2008 April 28; 168(8): 855-60

As with bioidentical hormone replacement of other essential hormones, high normal thyroid levels result in a host of benefits in addition to decreased cardiovascular risk: improvement in mood, weight loss, energy, cognition, hair and skin quality, and more.

With proper testing and monitoring, it’s possible to reverse symptomatic cellular hypothyroidism caused by suboptimal yet normal thyroid hormone levels. Doing so involves replenishing your thyroid hormone to the levels you had in your 20’s and 30’s and, in so doing, improving your health risks, quality of life, and well-being. The lab testing and screening process to assess eligibility for treatment is straight forward and the benefits potentially rich. If interested in such an evaluation, call 855.JUMPSTART to set up an appointment to learn more.

Additional articles are cited below for additional learnings. I’d like to thank Dr. Neal Rouzier, author of How to Achieve Healthy Aging for his help and support in the curation of the evidence based scientific support behind our approach to bio-identical hormone replacement therapy.

Other Scientific References

  • Thyroid Therapy Does Not Lead to Bone Loss
    “Long-term high doses of thyroid had no adverse effect in causing osteoporosis or fractures. “ Cortland Forum 2001 July: 85-90
  • “Even exceptionally high doses of thyroid do not cause osteoporosis or fractures.” Normal Metabolic Research 1995; November; 27(11): 503-7
  • “Long-term thyroid replacement with high doses has no significant effect in bone density or fractures.” Lancet 1992 July 4; 340(8810): 9-13
  • “In our study, we found significant association between low levels of T3, poor performance, and increased mortality.” Journal of the American Medical Association 2004 Vol 292 (21):
  • Fibromyalgia May Benefit from Treatment with T3 / T4 Combination
    Fibromyalgia is frequently seen in hypothyroidism. There is now evidence to support that fibromyalgia may be due to thyroid hormone resistance (cellular hypo-function)..” Medical Hypotheses 2003 August; 21(2): 182-89