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Originally published on 24th March 2016 Last updated on 12th October 2021
Although a lot of doctors will not tell you, there are more options for treating your thyroid than just T4-only medication such as Levothyroxine or Synthroid.
In fact, a lot of doctors don’t even seem to be aware that they can treat hypothyroidism with more than just synthetic T4-only drugs.
But could a change in medication change your life?
What’s The Difference?
A healthy thyroid gland would be giving you five hormones you need and these are: T1, T2, T3, T4 and Calcitonin.
- T1 is thought to play a role in keeping your thyroid function in check and also is believed to influence the heart.
- T2 likely plays a role in converting T4 to T3, which is very important and a reason why so many patients don’t feel much better on T4 only medicine, but more on that later. It also likely has an impact on metabolism and burning fat and is effective in increasing liver metabolism and that of the heart.
- Referred to as the ‘active hormone’, T3 has the greatest effect on the body’s energy levels and overall health and well-being. It is more active than T4. T3 is said to be linked to mental health, ability to coping with stress and emotional stability. T4 is referred to as the ‘storage hormone’ and its main function is to convert to T3, both active T3 and reverse T3.
- T4 is involved in brain function also.
- Calcitonin is secreted from the thyroid when blood levels are high in Calcium. It acts to lower levels of Calcium in the blood and stops the release of more Calcium from your bones into the blood. Because of this, it’s said to be effective in the prevention of osteoporosis.
Your body produces all of these hormones itself but some of the T4 produced by the thyroid is also converted into that very important T3 and T3 is the active thyroid hormone; the one that gives you energy and removes most hypothyroid symptoms.
So, you can see why it may be beneficial to take a thyroid medication that replaces all or at least the two most important (T3 and T4) of these thyroid hormones in the case of hypothyroidism.
Worth noting: calcitonin isn’t well absorbed orally, so may not have much benefit in NDT medications, and T1 and T2 are made outside of the thyroid gland, so are unlikely to be contained in NDT medications. 
Most conventional doctors believe that we only need to replace the T4, as we only require tiny amounts of T1, T2 and Calcitonin anyway, and our body will convert some of the T4 to T3, to replace that thyroid hormone. That seems simple enough, right? Wrong.
While some people do do well on synthetic T4-only meds, such as Levothyroxine and Synthroid, many other thyroid patients fail to convert the T4 in to T3, so when they take T4-only meds, they still feel unwell.
A conversion issue can be caused by an enzyme called iodothyronine deiodinase that is either deficient or not compatible for some people and is important in the activation and deactivation of thyroid hormones. T4 is converted into T3 by deiodinase activity. A problem with this can therefore cause conversion issues, where TSH can look ‘fine’, as well as Free T4, but with a low Free T3 and continued hypothyroid symptoms and development of other health conditions (such as mental health and heart/blood pressure problems).
Another cause could be adrenal fatigue (though it is more accurately referred to as hypothalamic-pituitary axis dysfunction), or vitamin deficiencies such as iron or selenium. By addressing these, you may fix the conversion problem, but many other people simply have a problem converting and don’t know why. So simply, they will likely benefit from taking a thyroid medication that gives them direct T3, instead of relying on their body to convert the T4 they put into T3 for them.
A study in 2018 showed that T4-only medication Levothyroxine was associated with a lower quality of life in those with Hypothyroidism.
Instead of being on T4-only, you could be on synthetic T3-only medication which skips that conversion stage. But as you have no T4 (the storage hormone) to convert to T3 for you, you may have to dose it more often, such as 3 or even 4 times a day. Still, many thyroid patients do feel an improvement over being on T4-only medication alone.
T3 and T4 Combination
There is also the option of taking both synthetic T4 and T3 together, to try and mimic more closely what the thyroid gland would be putting out, if it was working properly. Thyroid patients who have tried this do often report much better results than using T4-only on its own, as it gives you that direct T3 and doesn’t rely on your body converting it.
Natural Desiccated Thyroid (NDT) is most often dried porcine (pig) thyroid gland (bovine over the counter does exist) and gives you all of the thyroid hormones.
Most people seem to dose NDT twice a day, taking half their dose in the morning and the other half mid-afternoon. However, I multi-dosed my NDT for a few years and then recently went back to taking it once a day and saw no difference in how I felt at all. So for now I’m taking it once a day as it’s easier to manage.
NDT removes the need to rely on the body converting hormones.
A study published in the Journal of Clinical Endocrinology and Metabolism in 2013, titled Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study, compared NDT medication to T4-only medication in the treatment of hypothyroidism This significant study . It was published in May 2013. The results showed that almost half (48.6%) of patients preferred NDT, with 18.6% preferring T4-only, and 32.9% having no preference.
This study indicates that NDT can be superior to synthetic T4-only medication for many hypothyroid patients.
Compounded Thyroid Medication
Compounded thyroid medication offers the advantage of being made without any fillers, which can be useful if you do not tolerate them well, such as gluten or lactose. The amounts of T3 and T4 are usually similar to NDT, but doctors can order for the amount of each to be adjusted to make the exact dosage your own body needs. It is essentially more personalised. This can be the answer for those who do not feel well on synthetic T3, T4 or NDT medications.
Most compounded thyroid medications are ‘immediate release’ versions, which means that they release the active medication immediately after taking, but compounding pharmacists are also able to make sustained release versions, where the medication is released more gradually; continuously throughout the day.
So, What Do I Do?
If you’re currently doing well on your thyroid medication, then you don’t need to do anything.
But you may have read all of that and thought “Brilliant. How do I change to T3-containing medication?”
Well, the hardest part is trying to get your doctor to prescribe anything other than T4-only medicine, sadly.
The vast majority of conventional doctors have been trained to stick to T4 synthetics, so many patients these days are unfortunately having to go private to see a doctor who will prescribe other medication options or even self-source it online, which carries many risks, just to get the medication they need to function like a normal human being.
However, I am not suggesting that NDT is the only way forward, as some thyroid patients do do well on T4-only meds or one of the other options, but the problem is that doctors need to be treating patients based on their own individual needs, symptoms and reaction to medication.
What is the best thyroid medication?
The best thyroid medicine is the one that works best for that particular person.
This should include T3 and NDT medicine.
There is an excellent paper called Functional and Symptomatic Individuality in the Response to Levothyroxine Treatment which shows that everyone is individual and has different thyroid treatment needs. 
If you’re vegetarian, see this article.
Stop The Thyroid Madness cover all the different brands and ingredients of NDT, here.
If you are not feeling well despite being on thyroid medication, it could be because your test results are in the “normal” range but not at the “optimal” level for you.
Related Article: Signs Your Thyroid Medication May Need Adjusting
You can click on the hyperlinks in the above post to learn more and see references to information given.
Rachel Hill is the highly ranked and multi-award winning thyroid patient advocate, writer, speaker and author behind The Invisible Hypothyroidism. Her thyroid advocacy work includes writing articles, authoring books, producing her Thyroid Family email newsletters and speaking on podcasts, as well as being a founding board member for the American College of Thyroidology. She is well-recognised as a crucial contributor to the thyroid community and has a large social media presence. Her books include “Be Your Own Thyroid Advocate” and “You, Me and Hypothyroidism”.