If you’re suffering from hypothyroidism, or think you might be, it’s important to know that a thyroid conversion problem may be a hidden cause… and that conversion issues can’t always be solved with a prescription medication.

Low thyroid symptoms, such as fatigue, weight gain and sensitivity to cold, can appear when your body has difficulty converting the thyroid hormone T4 (thyroxine) into our most active thyroid hormone T3 (triiodothyronine), which does the vast majority of thyroid work. That conversion runs smoothly when everything’s in good shape, but unfortunately, there can be problems with that process.

Most doctors don’t know how to manage T4 to T3 conversion problems

When your thyroid is low enough that your doctor gives you a prescription for your condition, it’s almost always in the form of Synthroid, Levoxyl, or the generic version of those drugs — levothyroxine.

However, all of those drugs are just T4, and your doctor is prescribing them based on the assumption that T4 is going to convert to T3 in your body.

Most doctors believe this. It’s in medical textbooks and guidelines. And it’s true that in a healthy system, levothyroxine will help your body produce T3.

But there are numerous problems that can interfere with that conversion of T4 to active T3. If you’re making or taking T4 and it can’t get to T3, you simply can’t benefit from it. It’s like being all dressed up with nowhere to go!

Most conversion issues are reversible

Here’s some good news: all of the factors that can interfere with the production of active thyroid hormones are reversible, except for one. The vast majority of women will be able to turn these around and eventually not need, or be able to get off, thyroid hormone.

The number one factor that interferes with a T4 to T3 conversion is poor health. Any chronic illness, whether it’s an autoimmune disease, chronic infection, diabetes, insulin resistance, chronic fatigue syndrome, fibromyalgia or just about any another chronic condition, has the potential to interfere with T3 activation.

If this is the case for you, I really encourage you to work with your doctor or healthcare practitioner on that chronic condition to turn it around.

7 natural ways to reverse thyroid hormone conversion issues

1. Avoid crash dieting, which harms your metabolism

You’ve probably already heard about how crash dieting slows your metabolism way down. That’s because the body starts to think you’re starving. It doesn’t know that you have food in the fridge, so it senses real danger and slows down your metabolism.

woman eating a salad as part of a healthy diet

Your body does that by reducing your production of T3 from T4 to the point where, once you go off a crash diet, your metabolism is often so slowed down that you’ll actually require 500 or 600 calories less to maintain your weight once you go back to a regular diet. It can take the body a long time to reestablish your old norm — essentially, to trust again.

There are a lot of reasons to avoid crash dieting, but this is a big one.

2. Reduce inflammation

Inflammation is another big interfering factor in that conversion of T4 to T3.You may be aware that you have inflammation because you have the classic symptoms of pain, redness and swelling. Or, you may have low-grade inflammation with symptoms that are less obvious.

Inflammation can stem from chronic infections in the body, or from eating a standard Western diet that is high in flour products and sugar. Things like soft drinks, too many animal proteins, trans fats, or processed, fried, and fast foods all increase low-grade inflammation in the body.

You can also have inflammation from excess abdominal fat, because the fat that concentrates in the abdomen more easily churns out inflammatory cytokines, which are the mediators, or messengers, of inflammation. These cytokines directly inhibit the conversion of T4 to T3. If you have infections, which are often hidden, it’s important to get help resolving them. For instance, you could have an infection in the stomach from Helicobacter pylori or other “gut bugs” in the intestine, or Lyme disease, or a periodontal infection, which can be asymptomatic.

3. Eat an anti-inflammatory diet to prevent thyroid issues

Eating an anti-inflammatory diet will help move out those foods that cause inflammation.

  • Emphasize lots of colorful fruits and vegetables. They’re packed with compounds such as antioxidants that fight inflammation, and they’re also alkalizing. Eating sugar, white flour products, and a meat-rich diet makes our bodies acidic, which is directly correlated with inflammation. When we alkalize, it does the opposite — all that inflammation just calms right down.
  • Include clean proteins and healthy fats, which are not the trans fats from fried foods but rather fats like olive oil, coconut oil and cold-water fish, which are packed with healthy monounsaturated or omega-3 fatty acids.
  • Consider an omega-3 fatty acid supplement.
  • Eliminate reactive foods. Anything that causes an immediate allergic reaction (anaphylaxis in the extreme case) should obviously be avoided, but there are also many food sensitivities that can give us problems. Those immunogenic foods may trigger delayed reactions or symptoms, making it hard to pinpoint what’s causing the problem.
  • Try an elimination diet. If you’re not sure what foods, if any, are giving you trouble, then you should meet with your health care practitioner to get some help. An elimination diet and gradual reintroduction of foods can help you identify foods that are causing inflammation in your body every time you have an immune reaction to them.

4. Get serious about stress management for healthy cortisol function

The T4 to T3 conversion requires some degree of cortisol, the adrenal stress hormone, which is produced in response to stress and low blood sugar. That means that cortisol insufficiency, or not having enough cortisol (which can happen with chronic stress) can then cause you to have low thyroid function.

grandmother reducing stress by blowing bubbles with her grandson

The hypothalamic-pituitary-adrenal axis, or HPA axis, is the feedback system between the brain (which contains the hypothalamus and pituitary gland) and the adrenal glands, which lie on top of the kidneys. With chronic stress, the signals between the brain and the adrenal glands can be disrupted to the point where the body no longer produces enough cortisol. That can lead to low thyroid function on top of adrenal dysfunction.

You’ve heard it ad nauseum: “Manage your stress,” to the point where you may be immune to the words. Still, it’s important to remember that even if your mind gets used to a frantic pace, and you’re convinced you have to keep operating at that pace — even if you can fool your brain, your body never learns how to adapt to that pace. When our bodies can’t keep up, we ultimately pay the price. That’s why I strongly encourage you to manage the stress in your life, even if everybody else is running at top speed and it feels abnormal to go slower. It’s more important that you get adequate sleep and start taking extra good care of yourself.

Too much cortisol can also interfere with the conversion from T4 to T3. That can stem from acute emotional stress, or it can be related to physical, or physiological, stress. Infections, inflammation, allergies, hypoglycemia, or pain syndromes — even simply pain, alone — can all be factors that cause cortisol to surge.

5. Rethink low-carb diets

The T4 to T3 conversion also requires a certain amount of insulin, which is released by the body when we consume carbohydrates. Many people think of “carbohydrates” as a bad word these days, but there are good carbs and bad carbs, and we’re all different in terms of how well we tolerate certain foods. For example, some people can’t handle an extremely low-carb diet, and their insulin level may drop so low, as a result, that thyroid function is affected.

Just because a high-protein, low-carb diet is all the rage these days, that doesn’t necessarily mean it will work for you. If you feel bad on that diet, take your experience to heart and take care of yourself. You might want to get some help looking into the kind of diet that will work best for you. It could be that taking in some complex carbohydrates like beans, legumes, and some whole grains, which are very different from the simple carbohydrates in sugar and white flour products, can help keep your blood sugar stable and assist with insulin release.

Conversely, too much sugar in your diet can interfere with T4 to T3 conversion. If we eat a bunch of sugar and it pours into the bloodstream, we get a big spike in blood sugar (glucose). This can then cause the pancreas to overshoot when it produces insulin in response. That in turn causes your blood sugar to crash. One of cortisol’s functions is to help raise blood sugar when it’s too low. So, if you’re experiencing wild rollercoaster spikes in glucose and insulin, cortisol can overshoot, and you’ll be back to cortisol excess and interference with the production of active T3.

6. Check your minerals

Selenium is a cofactor for the enzyme that converts T4 to active T3. If you’ve had a poor diet for a while, especially if you’ve had gastrointestinal problems like digestive or absorption issues, you might be low in selenium and a number of other minerals. I recommend to people that they take a high quality multivitamin/mineral, along with a healthy diet.

Foods high in selenium

If testing confirms that you have elevated thyroid antibodies suggesting Hashimoto’s disease (chronic lymphocytic thyroiditis, which often leads to hypothyroidism), then I also recommend a selenium supplement daily. Be careful not to take too much selenium, though — 200 micrograms is a safe dose. There’s some evidence that selenium can help reduce those antibodies, and it helps the enzymatic conversion of T4 to T3.

Another consideration is iron deficiency anemia. Fatigue and hair loss are two possible symptoms of iron deficiency, but those are also common symptoms of low thyroid function. If you’ve had chronic digestive problems like low stomach acid or small intestinal bacterial overgrowth (SIBO), or especially if you’ve had a loss of blood over time, whether it’s from menstrual periods or some condition that’s caused bleeding, consider the possibility of iron deficiency. It’s very easy to check your iron status.

7. Avoid toxic chemicals

Certain medications can also interfere with the production of T3. For example, beta-blockers, especially propranolol, which is often given for hypertension, can interfere. Perflourinated compounds, which compose part of the nonstick surfaces on products like Teflon pans or the linings of microwave popcorn bags, can also interfere. Other examples include toxic compounds in cigarette smoke and smog, bisphenol A (BPA), and phthalates, which can be found in plastic containers, perfumes and personal care products. Some non-organic fatty foods are disruptive, as are toxic metals such as mercury, lead and cadmium.

Woman storing water in glass container

It’s impossible to avoid every chemical these days, of course, but there is a lot we can control. For example, buy organic produce. It can be easy to ignore the organic section in the store, especially if organics are more expensive, but the non-organic foods are the ones containing the pesticides. Healthier choices also include chemical-free meats and wild-caught fish. It might sound like the quality of farmed fish would be better controlled, but farmed fish is surprisingly toxic.

You should also store your food in glass containers instead of plastic, especially fatty foods, because the fat in the food can easily draw in chemicals from the container or wrapping. Use non-Teflon pans for cooking, and store your drinking water in glass water bottles instead of plastic. There’s a lot we can do to live as cleanly as possible in this increasingly polluted environment we live in!

There’s no one-size-fits-all answer

Lastly, there can be genetic variation in the enzyme that converts T4 to T3, just like there’s genetic variation in every other function in the body. We’re all unique, which is why one protocol doesn’t work universally in everyone.

One British study looked at 552 subjects with hypothyroidism, specifically at one particular mutation in a deiodinase enzyme that converts T4 to T3. Researchers found that a whopping 16% of those individuals had a mutation that slowed down that conversion. All of them had been on T4 medication. When they were given T4 plus T3, their symptoms improved.

As far as I know, the test for that mutation is not commercially available. But I bring it up because it drives home the reminder that we’re all different. Your doctor may be treating you according to a standard of care and expect you to be able to respond like the textbooks promise you will. But if you’re taking T4 and it’s still not working for you, even at a higher dose, then talk to your doctor about the idea of switching to a product with combined T4 and T3, such as Westhroid, Nature-throid, or Armour.

two women take selfies in the park

Or, if some of the other factors we’ve discussed here are relevant for you and you have a more significant conversion problem, it might be useful to take a compounded T3 product, which contains more T3 than you’d get in those other products. There’s even a time-release T3 that may be a safer way to go — there are many different options. Again, the whole point of these alternative hormone prescriptions is to bypass that potentially troublesome conversion step, to make sure you’re getting the T3 that you need.

As you can see, there are many different factors that can interfere with this function that our bodies were designed to carry out. The good news is that, with the exception of genetic variation, getting hung up at T4 and not making enough T3 is reversible. If any of these factors I’ve discussed are relevant for you, and you address them, you’ll likely experience a boost in your thyroid function.

If you’re already taking Synthroid or levothyroxine (T4), but not benefitting from it, talk to your doctor about possibly adding in some T3 and seeing what that does for you. Feeling better from such a change can be diagnostic in itself, indicating that a conversion problem is real for you.

Finally, if you are taking prescription thyroid medication but also starting to address some of these factors that are relevant for you, keep in mind that your thyroid function will be gradually improving along the way. What this means is that over time you might not need as much thyroid medication, and, at some point, need no prescription at all. It’s therefore important to monitor your thyroid markers along the way through your health care practitioner. You don’t need to do it more often than every few weeks, because it takes time for the body to adjust. If you do monitor your thyroid markers, you might just find that you can get off thyroid hormone completely.