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Why Your Thyroid Medication Isn’t Working

Why Your Thyroid Medication Isn't Working

Treating a thyroid condition usually involves prescribing a thyroid hormone replacement drug. The most common of these is levothyroxine, the generic version of synthetic thyroxine (T4). Unfortunately, most patients require more than simply increased T4 levels to achieve optimal thyroid function.

The thyroid is a complex system that involves a variety of factors. When functioning properly, these variables work together to help support the entire body. However, those with a thyroid condition can experience system-wide disruption. Hypothyroidism is the most common form of thyroid disorder, which can be caused by multiple issues such as poor conversion of T4 to T3, over conversion of T4 into Reverse T3, poor hormone transport and other patient-specific factors. To properly treat thyroid conditions, we must recognize that the one-size-fits-all approach of prescribing a synthetic T4 drug such as levothyroxine is rarely the right approach.

The Thyroid and T4

The thyroid influences nearly every tissue in the body and has a significant role in one’s metabolic function. To do this, the thyroid utilizes multiple hormones including T4, T3, T2, and T1. The most frequently discussed, and perhaps most important, hormones of this set are thyroxine (T4) and triiodothyronine (T3).

T4 is the inactive form of thyroid hormone which must be converted into T3, the active form of thyroid hormone, to have positive impact on the body. This is the hormone responsible for regulating numerous bodily functions. Many practitioners believe that increasing T4 levels via medications is the best method of resolving thyroid issues because they assume it will be correctly converted into T3. Unfortunately, conversion issues are a frequent cause of thyroid dysfunction and the addition of T4 to a broken system likely does more harm than good.
This partially explains why many patients continue to experience thyroid-related symptoms such as weight gain, depression, poor cognitive function, infertility, fatigue, reduced libido, and others, even after being treated with thyroid medication.

Misleading Signals

One of the reasons T4 medications have become the standard method of treating thyroid conditions is because it influences one’s TSH, or thyroid stimulating hormone, levels. TSH is the most widely utilized method of gauging thyroid health. Unfortunately, this approach misses a huge percentage of those with thyroid dysfunction. This testing method does not consider important thyroidal factors such as thyroid hormone conversion and transport. By improving one’s T4 levels, doctors can normalize TSH levels without ever dealing with the true cause of thyroid dysfunction. Without recognizing the presence of such conditions and properly treating them, it is likely that one will continue to experience thyroid dysfunction even though they are being treated with T4 medications.

Conversion Issues

There are multiple reasons why one may not be able to effectively convert T4 into T3. Genetic conditions, nutritional deficiencies (such as low selenium, omega-3 fatty acids, and zinc), and hormonal dysfunction can all contribute to conversion difficulties. Reduced levels of T3 can cause system-wide dysfunction and can be caused by poor T4 conversion. Many medical practitioners do not appreciate the importance of this process and simply place more T4 fuel onto the dysfunctional system. Part of the reason this practice is particularly dangerous is that T4 may be converted into more than just T3. Reverse T3 is the mirror image of T3 and acts as a thyroid hormone inhibitor. When the body over converts T4 into Reverse T3, one experiences hypothyroidism. If one’s system is regularly producing too much Reverse T3, additional T4 is simply going to exaggerate the imbalance and worsen the patient’s condition rather than improve it.

Poor Transport

To have any effect on one’s health, thyroid hormones must be able to reach the numerous tissues and cells of the body. Transport of thyroid hormones can be inhibited by a variety of common conditions including insulin resistance, diabetes, depression, bipolar disorder, hyperlipidemia (high triglycerides and cholesterol), chronic fatigue syndrome, fibromyalgia, neurodegenerative disease, migraines, stress, anxiety, and age related disease. Conversely, poor thyroid function increases the risk of developing these conditions meaning that one can fall into a vicious cycle of reduced thyroid function and degrading health. Inhibited hormone transport is another contributing factor of thyroid dysfunction that is not aided with the addition of more T4. Treating a thyroid condition of this nature with T4 is like loading a train with food to help resolve a famine on the other side of the country and then letting it sit in the station.

Autoimmune Disorders

A percentage of thyroid disease is caused by autoimmune disorders. The two primary culprits are Hashimoto’s Thyroiditis and Graves’ disease. These conditions damage the thyroid and are exceptionally difficult to diagnose through standard methods. If a patient is suffering from an autoimmune disorder while also being treated for a thyroid condition, they may continue experiencing symptoms such as muscle aches, fatigue, dry eyes, and hair loss, that are normally attributed to thyroid problems. This can cause one to feel that their medications are not helping resolve their thyroid issue even if they are. In the presence of an autoimmune condition, thyroid medication alone will not be able to resolve symptoms. A multi-system approach of optimization and systematic treatment must be used to return the body to normalcy.

What Does Better Testing Look Like?

The standard approach to testing via TSH and treating thyroid conditions with T4-only solutions is clearly not working. Experts suggest that 10 to 40 percent of Americans experience suboptimal, untreated, and undiagnosed thyroid issues. Because there are so many variables and unique factors involved in individual thyroid function it is important to pursue appropriate testing and treatment. To have a more complete understanding of one’s thyroid health a comprehensive test including Free T4, Free T3, Reverse T3, sex hormone binding globulin (SHGB), leptin, and basal metabolic rate, should be administered. Only then can doctors prescribe the appropriate medication and treatment method for one’s individual condition.

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7 Comments on "Why Your Thyroid Medication Isn’t Working"

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Hello, as a thyroid sufferer, I find your blog so helpful. I wonder if you could elaborate a bit more about why SHGB and leptin should be tested. I don’t think I’ve seen them mentioned before and would like to understand more about their links with thyroid issues. Thank you.

Naomi Parker

Hello Nigella,
We don’t have any articles on our site, but here are a few you may find useful: and (this link does say “weight loss”, however, the information discusses the impact leptin has on thyroid hormones). I hope this information helps!

– Naomi


W all this being said , what is 1 suppose to do ? I see a specialist for my thyroid & on medication & take the same time everyday , 1 don’t eat a entire hr. after , I stay away from foods/don’t drink coffee @ all , that might aggervate , etc . I go every yr. to be checked , I still struggle daily w all symptoms , I’ve discussed this w my Dr. , ? What to do ?

Naomi Parker
Hello Lisa, If you’re still experiencing thyroid dysfunction symptoms after being on medication there are a couple things that are probably going on: 1. You’re likely not on the optimal dose and/or medication. Discuss with your doctor an increase in dose or adding T3 to your medication. If they are unwilling, it may be time to search for a new physician. 2. You may be experiencing nutrient deficiencies in conjunction with the thyroid disease. You can find common nutrient deficiencies here: I would suggest asking your provider to test for these nutrient deficiencies and supplement if necessary. I hope… Read more »

Lisa, I was taking my medications, Armour, at bedtime and instantly felt 98% better. There is better absorption when taken at bedtime. Also, have your other hormones checked such as estrogen, progesterone and testosterone because all hormones work together. Also, if you have Adrenal fatigue this can affect your thyroid. Also, thyroid problems tend to deplete vitamins and nutrients, which I discovered and started taking adrenal vitamins daily at least twice a day.


A check of other hormones–estrogen, progesterone, testosterone–determined they were low and once those were within the range then I no longer needed thyroid medications. I have also started a strict vitamin regimen to restore and build better and stronger health so that thyroid problems will not be a problem in the future.

Ana silva

Where do you get basis of these recommendations?

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