The Proper Assessment and Treatment of the Thyroid

By Dr. Frank Aieta, N.D.

Assessing thyroid function is more complex than simply looking at TSH levels and making sure that it falls within the broad range of .4 – 4.5. Many factors need to be assessed through proper laboratory testing and evaluation of clinical symptoms. If your physician relies solely on checking your TSH to assess your thyroid then he is doing you a great disservice. In the following article I will discuss the great lengths at which I go to properly assess a patient’s thyroid function. This is achieved through taking the time to review a patient’s clinical signs and symptoms, running the correct thyroid blood tests and properly assessing adrenal function and nutrient status.

Thyroid dysfunction can occur at any age. If your level of production of this important hormone is low, you can develop symptoms of hypothyroidism. Any imbalance of your thyroid hormone can affect every metabolic function in your body. Your thyroid gland is your body’s regulator. It regulates energy and heat production, growth, tissue repair and development, and stimulates protein synthesis. Furthermore, thyroid hormones modulate carbohydrate, protein and fat metabolism, vitamin use, digestion, function of the mitochondria (energy makers of your cells), muscle and nerve action, blood flow, hormone excretion, oxygen utilization, and sexual function to list just some of its uses.

Your body produces more than one kind of thyroid hormone. The main hormones produced by the thyroid gland are T3 and T4. T4 is 80% of the thyroid gland’s production. T4 is essentially an inactive storage type hormone and needs to be converted over to T3 in your liver, kidneys and other tissues. T3 is five times more active than that of T4. T4 can also be converted to something called reverse T3, which I will be discussing more in detail later. Reverse T3 is actually inactive and can bind up the receptors where active T3 needs to go. Your body also makes T2. T2, although it is not tested in the blood, increases the metabolic rate of your muscles and fat cells, so it does play a role in the body. Low levels of T3 in the body can cause less cholesterol to be removed from your blood, which causes an elevation of LDL (bad cholesterol). People with low thyroid levels have cholesterol levels 10-50% higher than people with normal thyroid function. Moreover, even mild thyroid dysfunction is associated with heart disease.

The TSH (Thyroid stimulating hormone) test which is so widely used by many mainstream doctors as a stand alone test for the thyroid, actually measures a pituitary hormone and not a thyroid hormone. The pituitary is the body’s master gland, found in the brain and it controls the function of all the body’s other glands. It regulates the thyroid’s output of hormones by releasing more or less TSH. Typically if we measure TSH levels and they are low, this indicates the thyroid is producing enough or in some cases too much thyroid hormone so less thyroid stimulation is requires. If TSH is high it can indicate that the gland is not producing enough so more thyroid stimulation is required. The problem with solely relying upon this test is that the reference range for TSH is very large, ranging from .4 to 4.5, so many doctors will consider your thyroid normal if you fall within this range. The other problem with this test is that it doesn’t tell us what’s happening with the conversion of T4 to T3 in our tissues. Often times I will find that a person tests normal or even low on their TSH test but they are exhibiting symptoms of hypothyroidism (which we will discuss in a minute) and have a corresponding low level of Free T3 in their blood. (T3 free is the preferred way to measure T3 because it represents the actual thyroid hormones that are available to our cells and are not bound to protein or in the reverse T3 form.)

The following are signs and symptoms of low thyroid production (hypothyroidism):

  • Weight gain
  • Puffy face
  • Depression
  • Decreased sexual interest
  • Constipation
  • Cold intolerance
  • Headaches
  • Cold hands and feet
  • Brittle nails
  • Swollen legs, feet, hands or abdomen
  • Rough dry skin
  • Insomnia
  • Menstrual irregularities
  • Fatigue
  • Poor circulation
  • Low body temperature
  • Fluid retention
  • Hoarse, husky voice
  • Elbow or arm keratosis (Rough bumpy skin)
  • Low or high blood pressure

  • low speech
  • Muscle weakness
  • Anxiety
  • Agitation
  • Panic attacks
  • Sparse, coarse or dry hair
  • Decreased memory
  • Dull facial expression
  • Inability to concentrate
  • Yellowing of the palms and skin
  • Muscle and joint pain
  • Muscle cramps
  • Reduces heart rate
  • Drooping eyelids
  • Slow movements (reflexes)
  • Infertility
  • Morning Stiffness
  • Carpel tunnel syndrome
  • Dry and irritated eyes
  • Elevated cholesterol

In addition to assessing clinical signs and symptoms, I will always run a complete thyroid panel which includes: TSH, Free T3, Free T4, reverse T3, and thyroid antibodies (Anti-thyroglobulin antibodies and thyroid peroxidase antibodies). If antibodies are being made to the thyroid, they can stop thyroid hormone from attaching to your thyroid receptors. Consequently, you can get symptoms of decreased thyroid function even when your blood levels are adequate. Thyroid antibodies can be elevated due to trauma, poor digestive function, infection, inflammation, nutritional deficiencies, and thyroid degeneration.

Many factors affect how your body produces T3 and T4

Some factors that cause decreased production of T4 include a deficiency in: Zinc, Copper, Vitamins A, B2, B3, B6 and C. So it becomes important to test for these nutrients and supplement with adequate amounts. Most mainstream physicians don’t even know that these nutrients play a role in thyroid function so they would never even think of testing for them.

Furthermore, your body needs to be able to convert T4 to T3, the more active form. The conversion of T4 to T3 requires an enzyme called 5’diodinase.

Elements that affect 5’diodinase production are:

  • Selenium deficiency (this can be checked via blood)
  • Stress (all of my patients get counseled on stress management) 
  • Cadmium, mercury or lead toxicity (these are toxic metals that I will routinely check for when evaluating a patient) 
  • Starvation or low calorie dieting 
  • Inadequate protein intake 
  • High carbohydrate diet (all my patients go on a high protein, moderate fat, low carbohydrate diet) 
  • Elevated cortisol (Cortisol is an adrenal hormone that I will always assess through blood or saliva testing)
  • Chronic illness 
  • Decreased kidney or liver function (often seen in diabetics)

Nutrient deficiencies that cause and inability to convert T4 to T3:

  • Iodine (can be checked through an special iodine loading urinalysis test) 
  • Iron (assessed through checking a patient’s Ferritin levels (storage form of iron) 
  • Selenium
  • Zinc 
  • Vitamins A, B2, B6, B12, D

Medications that cause an inability to convert T4 to T3:

  • Beta blockers 
  • Birth control pills 
  • Estrogen 
  • Lithium 
  • Phenytoin 
  • Theophylline 
  • Chemotherapy


  • Too many Cruciferous vegetables in the diet
  • Low protein diet 
  • Low fat diet
  • Excessive alcohol use 
  • Soy 
  • Walnuts


  • Aging 
  • Stress (all of my patients get counseled on stress management) 
  • Bromine, Fluoride, Chlorine (I will routinely check patients for elevated levels of these toxic halides) 
  • Lead and Mercury 
  • Radiation 
  • Stress (mental and physical) 
  • Surgery 
  • Excessive copper or calcium
  • Dioxins, PCB’s and Pesticides
  • Low production of DHEA or Cortisol (both are adrenal hormones that are assessed through blood or saliva)
  • Phthalates (chemicals added to plastics)
  • Dioxins, PCB’s and Pesticides

If you cannot convert T4 to T3 adequately, you will have symptoms of low thyroid function. This is true if you have low T3 production or high reverse T3.

Factors associated with decreased T3 or increased reverse T3:

  • Increased catecholamines (epinephrine, norepinephrine) 
  • Increased free radical production (due to low levels of anti-oxidants in the body) 
  • Aging
  • Fasting
  • Stress 
  • Prolonged illness
  • Diabetes 
  • Toxic metal exposure
  • Elevated inflammatory markers (IL-6, TNF-alpha, IFN-2)
  • Low production of DHEA or Cortisol (both are adrenal hormones that are assessed through blood or saliva)
  • Phthalates (chemicals added to plastics)
  • Dioxins, PCB’s and Pesticides 

Furthermore, things that impair your body’s response to T3 will cause you to have symptoms of low thyroid. These include iron deficiency, and physical inactivity. There are factors that will increase the conversion of T4 to T3 of not enough T3 is being made by your body.

Factors that increase the conversion of T4 to T3:

The nutrients: Selenium, Potassium, Iodine, Iron, Zinc, Vitamins A, B2, C, E and D, and Tyrosine (amino acid)
The hormones: Testosterone, Insulin, Glucagon, Growth hormone, and Melatonin
Diet: High protein, moderate fat, low carbohydrate, no sugar
Herbal supplements: Ashwaganda, Guggul, Coleus forskohlii, and Rhodiola

As you can clearly see, proper thyroid assessment can be very complex. In my practice I continuously see overt mismanagement of patients with thyroid dysfunction by the so called “experts in the field of endocrinology,” the mainstream endocrinologists. This is due to their lack of training in nutritional medicine and the reliance on T4 only containing thyroid medications such as Synthroid or Levothyroxine to completely manage thyroid patients. I can honestly say that the majority of patients that I see who are being treated with just Synthroid are still overtly hypothyroid based upon their clinical symptoms and their low levels of free T3 on their blood tests.

Many times thyroid dysfunction can be resolved with proper diet, lifestyle and nutritional supplementation alone. In cases where thyroid hormone replacement is required, natural thyroid hormone replacement through the use of T4, T3 and T2 containing glandular products can be used. Research has shown that replacing T4 and T3 is more effective than replacing T4 only. One study revealed that 45% of people on T4 and T3 replacement scored better on mental agility tests. 67% of these people studied stated they had a significant improvement in mood and physical health.1


  1. Samuels M. H. (2014). Psychiatric and cognitive manifestations of hypothyroidism. Current opinion in endocrinology, diabetes, and obesity21(5), 377–383.