080 // T4 from converting to T3? This might be why.

Health with Hashimoto’s is your free weekly podcast to discover true, simple, and sustainable tips to improve your energy and health.

Some people do not convert T4 (inactive thyroid) to T3 (active thyroid) very well. Are you one of them? And what can you do about it? Answers in this episode!

This is IMPORTANT to know if you are taking a T4 medication like #synthroid or #levothyroxine . It’s also important if your thyroid is still making your own T4.

Because if you are making enough T4, but not converting it to T3, you might not have a thyroid problem—it’s something different!

You will find this episode below in audio format and a written summary because I know not everyone is an audio learner. Some links may be affiliate links that will support me without increasing your price.

Each episode of Health with Hashimoto’s is for informational and educational purposes. Please discuss any questions or concerns with your trusted healthcare professional.

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Related Episodes:

Episode 3 – What do my thyroid labs mean?

Episode 69 – Estrogen and Hashimoto’s (has liver tips)

Episode 24 – Your adrenal glands, chronic stress, and Hashimoto’s autoimmune disease


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The Calcium-Magnesium supplement I take at bedtime



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T4 from converting to T3? This might be why.

When you have hypothyroidism or Hashimoto’s, sometimes it feels like you have absolutely no energy.


Surprisingly, the culprit might not be the production of thyroid hormone T4, but rather its conversion into the active T3 form that the body can utilize effectively.

Your Low T3 Might Not be a Thyroid Problem

One of the reasons for that is perhaps not your thyroid at all! Maybe your thyroid is producing enough thyroid hormone, T4, but it’s not getting converted to the type that your body can use, the T3. This also means that your thyroid medication (Synthroid, Levothyroxine, etc) might not be giving you the thyroid hormone you need.

When you’re short on T3, you’re going to be short on everything that relies on that little ignition switch for the cell—like energy. Being deficient in T3 can have a cascading effect on your overall well-being. Energy, which relies on this cellular ignition switch, becomes a precious commodity. In this scenario, addressing the root cause is the key to regaining control over your vitality.

So today, I’m going to answer two questions:

  • What stops T4 from converting to T3?
  • What can I do to help my body convert T4 to T3 again?

As always, I will give you simple and sustainable tips so you can be empowered to create better health!

Deciphering Thyroid Labs: The Role of T4 and T3 in Energizing Every Cell

You might need a quick lab refresher: episode three is all about your labs and what the different things do. But essentially, you need to know this: Every single cell needs a little spark plug to work. T3 that is that spark plug—or like gas in your car.

However, your thyroid creates T4, and then that has to be converted to be able to be used. Sometimes the T4 gets converted to the brakes instead of the gas. It’s like a parent giving their overtired kid a nap instead of caffeine. That is kind of what reverse-T3 is. It’s the T4 getting converted to the brakes. It’s to help you slow down so that you have to prioritize rest and healing.

And really, what we all want is T3 We want more energy and the ability to continue doing because we have a lot to do. We are very busy. We have a lot of different things on our plates. So naturally, we want to maintain our energy. We want to build that energy so we can get things done.

Your Liver: The Top Reason T4 is Not Converting to T3

So let’s talk about why T4 to T3 conversion doesn’t happen. The main place that T4 is converted is your liver. So obviously, one of the things that we’re going to focus on is our liver health and helping our liver to not be congested.

Episode 69 is primarily about estrogen, but estrogen has to do with the liver because the liver processes estrogen. So I gave you a lot of liver-health tips in episode 69. Basically, you want to help your liver to do what your liver is supposed to.

I hear people, especially in the medical world, talk about your body as if we were like 200 or 300 years ago. And they believe your liver can still detoxify everything you encounter, just like it’s done throughout history.

However, we live in the 2020s where we are surrounded by different environmental chemicals and toxins that our bodies have to process and deal with. These are things that nobody was exposed to even 50, 60, 70 years ago. There are more and more put on the market every single day. It’s kind of scary to look up info on how many different chemicals are put into our world every single year. It’s absolutely crazy.

Do You Have Enough “Ingredients” to Convert T4 to T3?

The second reason you are not converting T4 to T3 well could be because you don’t have the ingredients. You need selenium.

Selenium helps your body convert T4 to T3. When I first started looking into thyroid stuff, that was one of the first things I learned. You need 200 mcg of selenium every day which is approximately the amount in two brazil nuts. That’s pretty easy to do right? A lot of supplements also have selenium in them especially the thyroid-specific supplements. For your body to convert the inactive form, the T4 to T3, you have to have selenium and you have to have enough selenium.

Liver congestion is the biggest problem in the (non)conversion of T4 to T3. And selenium is the easiest one to tackle. So I gave you both ends of the spectrum. Now let’s go towards the middle.

How Cortisol Blocks the T4 to T3 Conversion

One major theme of this entire podcast/blog is stress. It impacts everything including your thyroid hormones. Stress can stop the conversion or slow the conversion of T4 to T3. It’s specifically your stress hormone, cortisol, and we have talked about that before. But when your cortisol is up, it slows your T4 to T3 or it stops it. It prioritizes conversion to reverse T3 because increased stress/coritisol means you have an increased need for rest and recovery.

In addition to working on stress in general, you also want to support your adrenal glands which are the little glands that put out the stress hormones.

One other problem of stress is that it can cause your cells to be less receptive to your thyroid hormones. So even if you are making enough T4 and converting to T3 adequately, your actual cells might be less sensitive. In other words, you can still feel like you are hypothyroid.

Holistically Reducing Stress is Key for Thyroid Function

When I was doing the research for this episode, I was just struck over and over how everything is related. You really cannot work on just one thing. Your body just doesn’t work that way. Your body, mind, spirit, diet, environment is all connected. You are a whole person. That’s why I have that five-petaled flower in my logo, because you’re whole. Each of those is connected. Everything you do will impact the whole as well as other individual components of your health.

Stress is related to everything. It makes your tissues less receptive to the thyroid hormones and also stops the conversion. So, what can you do about your adrenals and stress? I have several episodes on this including episode 24 where I discussed chronic stress and your adrenal glands. While there are other stress-related episodes, this one specifically addresses the impact of chronic stress on your adrenals.

However, there’s a unique stress-relief tip I haven’t covered in the stress episodes yet. Reading fiction books can decrease your stress, lower anxiety, improve depression, and contribute to your overall health. Personally, I love to read. It’s my go-to relaxation method. I don’t really watch TV. Instead, I love to snuggle in bed and lose myself in relaxing book.

A Genetic Mutation Can Block Conversion of T4 to T3

You can improve everything I’ve already mentioned, but there is one thing you cannot change and that is genetic mutations. You might have heard of the MTHFR gene mutation, but there’s another genetic mutation that has a long name: Thr92Ala-DIO2 polymorphism. According to this article, one in five people has this mutation, and if you have it, you might struggle to convert T4 to T3 adequately.

So, what does this mean for you? You don’t necessarily have to get genetic testing to figure this out, although you can if you want. If you’ve been taking T4 medications like levothyroxine or Synthroid and still feel low on energy, or if your blood tests show that your free T3 is still low, your body might not be converting properly. In such cases, you can explore other approaches I’ve discussed, but you might also need T3.

T3 can be obtained through medications like Armour Thyroid which is a blend of T4 and T3, or Natural Dessicated Thyroid (NDT) or a stand-alone T3. It’s essential to note that T3 has had a bad reputation due to misuse in the past, leading to hyperthyroid effects like heart palpitations and anxiety. However, when used correctly and under medical guidance, it can be beneficial. One study found that people generally felt better when taking a combination of T4 with T3.

T3 is available as pills (Liothyronine, Cytomel) and as a cream. However, obtaining T3 might require some extra discussion with your doctor and even out of pocket payments since insurance companies won’t always cover it. Remember, I’m not a doctor, and I’m not prescribing or recommending. I’m here to empower you with information and knowledge so that you can have informed conversations with your healthcare provider.

Nourishing Your Body for Optimal T4 to T3 Conversion

So the main things that stop T4 to T3 conversion would be number one, your liver. Number two, your stress. Number three, you don’t have the ingredients like selenium. And then there’s that genetic mutation. So what can you do? Lt’s go back to #3 and discuss more simple things to ensure that you’re getting the essential ingredients.

Take vitamin A, for example. It is crucial for liver function. While you can get beta-carotene from a vegan diet, achieving adequate vitamin A levels often requires some animal sources. This is probably why we’re observing more thyroid problems in long-term vegans, as specific nutrients may be lacking.

Magnesium is another vital nutrient, and the number one mineral deficiency in the Western world. Magnesium controls over 300 different functions in the body. Among these functions is the conversion from T4 to T3. While the general population is often deficient, people with thyroid problems can have even more of a need for magnesium.

Supplementing magnesium is often necessary, especially considering that most multivitamins may not provide sufficient amounts. I take a blend of calcium and magnesium at bedtime. It not only aids in my sleep but also helps with muscle relaxation.

I personally started taking magnesium during pregnancy to alleviate my leg cramps and restless legs in the third trimester. The positive effects on muscle relaxation and sleep quality made me a believer, and I’ve continued using it since.

When supplementing with magnesium, it’s essential not to take it with thyroid medications to avoid potential interactions. Ensuring you get these vital nutrients can contribute to a healthier thyroid and support the conversion of T4 to T3.

The Role of Multi-Nutrients for a Balanced Approach to Thyroid Health

In the intricate dance of your body’s processes, various components demand different resources, nutrients, and specific levels to function optimally. Supplementing with individual nutrients can be tricky, as they need to be in balance. Over the past 5-10 years, there’s been a surge in multi-nutrients that focus on the synergy and balance of nutrients, offering more options than ever before. But most of them contain nutrients that, when taken together, counteract each other.

What I’ve found effective is taking a multi-nutrient designed with time-wise technology. The multi-nutrient I use is divided into morning and evening doses, ensuring that ingredients don’t counteract each other.

I take this multi-nutrient twice a day, specifically designed to enhance my energy levels during the day and provide additional minerals in the evening. It also contains adaptogens, which support your body’s ability to adapt to stress.

The multi-nutrient I recommend is from LifeVantage, the same company behind Protandem NRF2 activator. Using products from the same company ensures a cohesive approach, preventing imbalances.

LifeVantage offers a range of products, including many I’ve talked about on previous episodes. They make the NRF2 activator, NRF1 for mitochondrial support, the multi-nutrient, and more. I believe in their products due to their effectiveness, and it’s convenient to manage subscriptions and explore various health-enhancing options from a single source.

This episode has been longer than usual, and I appreciate your patience. I hope it sheds light on why your body might struggle with T4 to T3 conversion and empowers you to make the best decisions for your health.

Photo by Diego PH on Unsplash

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Hand holding an unlit lightbulb against a sunset sky. Text reads: What can block conversion of T4 to T3? Health with Hashimoto's
Hand holding an unlit lightbulb against a sunset sky. Text reads: Armour vs Synthroid; why you might need T3 instead of just T4. Health with Hashimoto's
Hand holding an unlit lightbulb against a sunset sky. Text reads: Still feeling hypothyroid even on Synthroid? Maybe your T4 is not converting to T3. Health with Hashimoto's