Root Cause of Hypothyroidism

Hypothyroidism is one of the most common conditions I encounter in women. It is also the most mismanaged condition that I see in women. 

Here are a few scenarios that I see in practice:

  • Your doctor told you that your thyroid was normal based on one blood marker (TSH). But you still suffer from fatigue, hair loss, dry skin, constipation, and depression. Your doctor tells you that you are just depressed and writes you a prescription for an anti-depressant.
  • Your TSH comes back high based on the lab reference range. Your doctor tests your T4, but it is "normal". Your doctor tells you that they will wait for you to get worse before doing any treatment.
  • Your TSH comes back high based on the lab reference range. Your doctor tests your T4 and it is low. Your doctor writes you a prescription for Synthroid. You don't feel any better.

To learn more about thyroid hormone labs, click here.

If you want to feel better with hypothyroidism, you need the right treatment. To figure out the right treatment, you need to know the root cause. It is as simple as that.

Root Causes of Hypothyroidism

1. Autoimmune Thyroiditis aka Hashimoto's

An autoimmune attack on the thyroid is a very common cause of hypothyroidism. But this is not a thyroid disease. This is an autoimmune disease that affects the thyroid and causes hypothyroid symptoms. All the Synthroid in the world will not fix Hashimoto's. You have to treat it like an autoimmune disease. Click here to learn more about an integrative approach to autoimmune disease.

2. HPA Axis Dysfunction

Your hormones do not exist in a vacuum. They interact and interfere with each other all day long. For women, we have to look at the interplay of thyroid hormones, adrenal hormones, and ovarian hormones. 

Issues with the hypothalamic-pituitary-adrenal axis can interfere with your thyroid is multiple ways. See this post for more details. The bottom line is that often, the primary issue is not the thyroid. It is the adrenals and how they affect the thyroid. As long as the only treatment is Synthroid, you will probably continue to feel worse and not better because the Synthroid is simply trying to cover up the real problem. 

You have to treat the HPA axis. Many women have come to my practice on thyroid medications, but they feel worse than ever. Once we treat the HPA axis, they are able to discontinue the thyroid medications and feel better than ever.

Click here to learn more about treating the HPA axis.

3. Estrogen Excess

Once again, your hormones do not exist in a vacuum. They interact. 

Estrogen increases thyroxine-binding globulin (TBG), a protein that binds to thyroid hormones in the blood. In order for thyroid hormones to act on your cells, they need to be free of TBG. If you have high amounts of TBG, you end up with low amounts of free thyroid hormone.

Estrogen excess is a very common hormonal imbalance in women. Causes of estrogen excess include use of oral contraceptives or hormone therapy, impaired metabolism and detoxification of estrogen, exposure to xenoestrogens, perimenopause, increased body fat (fat cells make estrogen), and receptor hypersensitivity. 

4. Insulin and Leptin Resistance

The research shows that insulin resistance is common in those with hypothyroidism and even autoimmune thyroiditis. And it is a two way street. Thyroid hormones impact blood sugar metabolism and can contribute to insulin resistance but insulin can also impact the thyroid gland.

Now, an overlooked hormone tied to insulin resistance is leptin. Leptin is the hormone that tells our brain that we our full. But we can develop leptin resistance where our brain becomes numb to those signals. This leads to weight gain, but it also impacts thyroid function. High leptin causes your body to convert T4 into reverse T3. Reverse T3 is an inactive form of thyroid hormone that cannot be activated AND interferes with T3.

High reverse T3 creates thyroid resistance and presents just like hypothyroidism. This is why it is really important to get your reverse T3 tested. So many of my patients come in with hypothyroid symptoms but tell me their thyroid is normal. And yes, their TSH, free T4 and free T3 are often within normal range and may even be optimal, but I will often find that their reverse T3 is elevated and fully responsible for their symptoms. 

4. Poor conversion of T4 to T3

Remember T4 is the inactive thyroid hormone. It is T3 that is the active hormone that tells your cells messages about metabolism and energy. So many doctors only look at TSH and T4 when evaluating thyroid hormones. But you have to look at T3. A very common pattern is normal T4 but low T3. T4 is converted to T3 in the liver and the gut primarily. So causes of poor conversion include impaired liver function usually due to issues with detoxification, insufficient stomach acid, bile or pancreatic enzymes, poor diet, gastrointestinal inflammation, imbalances in gut bacteria, as well as certain nutrient deficiencies such as selenium or zinc. 

5. Thyroid Resistance

Thyroid resistance is when the thyroid receptors stop responding to T3. This can happen for a number of reasons. It may be that reverse T3 is blocking the thyroid receptor. High reverse T3 can be caused by leptin resistance, poor sleep, low calorie diets, and HPA axis dysfunction.

Another form of thyroid resistance is when the receptor's sensitivity to T3 is modulated. One theory is that this happens when thyroxine-binding globulin (TBG) is low. This results in high amounts of T3 that overwhelm the receptors causing them to shut down and stop listening. Low TBG may be caused by excess androgens. Inflammation can also modulate receptor sensitivity, causing thyroid resistance.

treating hypothyroidism

The first step to proper treatment is to identify the root cause. To identify the root cause, you need to do the right testing.

Recommended thyroid testing

  • TSH
  • Free T4
  • Free T3
  • Reverse T3
  • Anti-TPO
  • Anti-TG

Other recommended tests

  • Fasting insulin
  • Fasting leptin
  • Fasting blood glucose
  • Hemoglobin A1c
  • DUTCH Complete (4 point cortisol/cortisone, sex hormones, and sex hormone metabolites)

Alternative hormone testing

You may not have access to the DUTCH complete test with your doctor. But there are other tests you can do.

  • 4 point salivary cortisol test OR AM serum cortisol (least preferred)
  • Serum sex hormones on day 21 of your cycle

Once you have identified the underlying issues, you can then pick the most effective treatment for your hypothyroidism. It is important to keep in mind that the right treatment is never just a pill (natural or otherwise). If nutrition, exercise, sleep, and stress management are not in place, supplements will not be effective.