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If you have hypothyroidism or have had your thyroid removed, you will need thyroid hormone replacement medication to maintain healthy levels of thyroid hormone. In most cases (but not all!) you will need to take this medication for the rest of your life. There are many different options for thyroid medications, including both natural and synthetic forms.

You might assume that a natural form of thyroid medication is better (I did) because, after all, it’s natural. But this may not be the best choice for everyone–or even anyone. Here’s what you need to know about both natural and synthetic thyroid medications to make the best choice for your body.

Your Thyroid is the Master Gland

Your thyroid is the powerhouse of your body, and a healthy thyroid is crucial for overall health and balance. Thyroid hormones impact brain function/cognition, hormone balance, fertility, GI function, body temperature, cardiovascular function, and lipid/cholesterol metabolism. The thyroid also regulates other hormones including insulin, cortisol, estrogen, progesterone, and testosterone. It’s crucial for metabolic balance (read: the ability to maintain healthy weight and burn fat effectively).

If your thyroid is underfunctioning, many other body systems suffer. It’s estimated that as many as 25 million Americans have a thyroid disorder, and over half are unaware. Hypothyroidism is more common than hyperthyroid–overactive thyroid–and thyroid disorders affect women far more often than men.

When your thyroid isn’t functioning properly, you may notice weight gain or difficulty losing weight, hair loss, dry skin, menstrual issues and heavy periods, constipation, depression, anxiety, infertility, and cold hands and feet. Read more about hypothyroidism here. The important thing to keep in mind for this post, and especially if you have hypothyroidism, is that your thyroid produces T4 and T3 hormones, both of which need to be in OPTIMAL levels for you to feel good. Read this post to learn more about optimal levels. It’s not good enough–and you won’t feel right–to just have your levels be anywhere within the normal reference range on lab work. Your levels need to be optimal. Get your thyroid levels checked at least every 6 months! More if you’re trying to optimize your dose.

Thyroid Medications: My Saga

First off, a little background to help you understand why this information is so deeply important and personal to me. I was first diagnosed hypothyroid when I was 35. I’ve now been on thyroid hormone replacement for 10 years.

Now, because I’m deeply entrenched in the holistic health and natural medicine sphere, and because I study this stuff for a living, when I went to see my naturopath about meds to treat my hypothyroidism, I knew exactly what I wanted: Nature-Throid. It’s a natural, desiccated pig thyroid that contains T3 and T4, the hormones you need for thyroid replacement. I wanted the natural option, and I liked that it provided T3 and T4 hormones, which is not what Synthroid, the most popular prescribed thyroid medication, provides. Synthroid is a T4 only med (more on that later).

Most of my colleagues recommended Nature-Throid, so it felt like a fine option. Nature-Throid has been around since the 1930s but has never been FDA approved (something that didn’t bother me at all since I don’t want the government involved in my medications. I’ve since changed this viewpoint, but at the time, that’s how it was).

It can take a while to determine your proper dose, and this was true for me. I started on a very low dose, 1/2 a grain or (32.5mg). That was too little. 3/4 a grain (48.75mg) was too much: I experienced extreme anxiety and heart palpitations, common symptoms of being overdosed. Not fun. Because 1/2 grain was too little and 3/4 grain was too much, I needed to get a custom compounded natural desiccated thyroid option comparable to Nature-Throid. My local integrative compounding pharmacy offered that no problem.

I tested my thyroid regularly, usually every 3 months, to make sure my levels were optimal. For a while, they were. But my thyroid hormone levels and TSH were always fluctuating. Hashimoto’s thyroiditis can cause fluctuating TSH levels, but my tests showed I didn’t have Hashimoto’s. So that wasn’t the problem.

During these years I also experienced heart palpitations on and off, a sign that thyroid meds could either be too high or too low. I constantly needed to adjust my dose which was incredibly frustrating. I figured it was just me. But when I started delving into the research and discussing further with my doctor, what I found infuriated me. And I finally figured out why I had been frustrated, and at times suffering, on and off for nearly 10 years.

Types of Thyroid Medications

There are two types of thyroid meds you can use: synthetic (man-made) or natural (comes from pigs typically). Natural thyroid hormone is often referred to as natural desiccated thyroid or NDT.

The most common NDTs are Armour, WP thyroid, NP thyroid. and Nature-Throid. Desiccated (dried and powdered) animal thyroid is now mainly obtained from pigs and used to be the most common form of thyroid therapy until synthetic meds hit the market. You must have a prescription to get these meds. I have tried Nature-Throid, NP Thyroid, and WP Thyroid and have had problems with all these.

For synthetic thyroid hormone replacement, the standard is L-thyroxine, or levothyroxine which is bio-identical T4. That means it’s identical in shape to your body’s own T4 thyroid hormone. The main types of prescribed levothyroxine are Synthroid, Levoxyl, and Levo-T. Synthroid (T4) is the most common drug prescribed for hypothyroidism, but in some people, T4 only drugs may not fully resolve hypothyroidism because your body also needs adequate levels of T3. T4 is supposed to convert into T3 in the body, but this doesn’t always happen (that was the case for me when I tried synthetic T4). In this case you’ll continue to have hypothyroid symptoms and may need T3 or other supplements to help you convert T4 to T3.

Common with T4 only drugs like Synthroid when the body doesn’t convert the T4 to T3. You may feel like T4 only isn’t working.

There’s also synthetic T3 called Cytomel or liothyronine, but it is not commonly prescribed.

Thyroid Medications: What You Need to Know

Since pills made from animal thyroid, in the case of NDT, are not purified, they contain hormones and proteins that never exist in the body outside of the thyroid gland. While desiccated thyroid contains both T4 and T3, the balance of T4 and T3 in animals is not the same as in humans, so the hormones in animal thyroid pills aren’t necessarily “natural” for the human body. A lightbulb went off for me when I learned this.

NDT extracts have three and a half times more T3 in relation to T4 compared to the ratio produced by a healthy human thyroid gland. That could lead to too-high T3 levels, which might affect heart health, bone density and cause symptoms normally found in people with an overactive thyroid. (source: American Thyroid Association).

Further, the amounts of both T4 and T3 can vary in every batch of desiccated thyroid, making it harder to keep blood levels right. (!!!!!) Bingo: this is exactly what was happening to me. The strengths can vary from batch to batch even if the dose is listed as the same dose. And many NDTs have been recalled over the years such reasons. Government health groups consider NDTs “high risk” for people age 65+, and Medicare doesn’t cover them due to higher risk for dangerous, off-beat heart rhythms in older people who may have heart problems. (source) This is why many conventional doctors are reluctant to prescribe NDT today.

I cannot tell you how frustrating it was to get my prescription refilled and have it be different than it was last month for whatever reason: sometimes there was a shortage of the med I was taking (happened frequently with WP thyroid), sometimes they used a different NDT preparation, and sometimes the strength was too weak or too strong (happened a lot with Nature-Throid, which was eventually recalled in 2020 for sub-potency). Read more about that here. This article discusses the mass recalls of NDTs in 2020. Really not OK.

EDIT: a week after I published this post, I received a letter (below) from RLC labs, the manufacturer of Nature-Throid and WP Thyroid stating they recalled all batches of WP and Nature-Throid for the past year (!!!) due to potency issues. Wonder how many times this has happened now. Anyone want to start a class action suit?

Finally, even desiccated thyroid pills have chemical binders in them to hold the pill together, and many people, especially those with Hashimoto’s, react poorly to these binders. I do not recommend NDT to anyone anymore. Read more about problems here.

The final straw for me was when I switched to WP Thyroid again after inconsistencies in my NP Thyroid RX. I took a few months of WP, and my labs were fine. I refilled my RX for the exact same prescription of WP and didn’t feel right, so I tested my levels and they were wildly out of whack. To make things worse, my TPO antibody levels were elevated (an indicator of Hashimoto’s), and that was a first. Turns out WP Thyroid was also listed as having major issues with sub-potency. I was furious (a recurring theme you’ll notice when I discuss NDTs).

Which Thyroid Med is Right for Me?

After 10 years of suffering with NDT, I’d had enough. I asked my doctor to switch my RX to synthetic T4. The benefit to this of course is you know what you’re getting every time. I tried that for a while but gained 5 pounds and felt depressed. I wasn’t converting enough T4 to T3, so we added in a low dose (5 mcg) of synthetic T3. Bingo! I felt like my old self again! I was so happy.

These days I take a combo of synthetic T4 and T3 (levothyroxine and liothyronine). I use a compounding pharmacy that makes a customized dose for me: 90mcg of T4 and 5 mcg of T3. They use the purest forms of T4 and T3 with no fillers and are able to customize my dose however I need. This has been a godsend because synthetic T4, the most common RX, was not right for me and often isn’t right for my clients. Sometimes taking thyroid support products like this Thyroid Synergy can help, as it contains vital nutrients that help your body convert T4 to T3.

To figure out what’s best for you, determine if you might be sensitive to any fillers used in meds, and decide if you want to go NDT or synthetic. If synthetic, determine if you are ok with T4 only or need a combo of T3 and T4. Some people are still reporting success with Armour NDT, but I personally never tried that and it does contain fillers to which some people react. At this point, I personally am no longer comfortable taking or recommending NDT.

Additionally, the American Association of Clinical Endocrinologists and the American Thyroid Association do not recommend using NDT to treat any form of hypothyroidism. NDT or any medication that combines T3 and T4 hormones should not be used during pregnancy.

In one study of 70 people with primary hypothyroidism, researchers started patients on either Armour Thyroid or levothyroxine(T4 only) for 16 weeks. They then switched patients to the other medication for another 16 weeks. At the end of 32 weeks total, they looked at things like symptoms and quality of life. They concluded that there were no significant differences in symptoms or quality of life reported in either group. HOWEVER, people do report more weight loss success taking Armour or adding in T3 to their synthetic T4.

Bottom Line

As with diet, there is no single thyroid replacement med that will be right for everyone. Some people might do fine on synthetic T4, while others may need T3/T4 combo. Some might be fine on Armour. This depends on your body, and make sure to closely monitor your thyroid hormone levels via lab testing. You can order your own thyroid labs here (thyroid panel complete near the bottom of the page) or here (test kit that comes to your house. This link gets you a discount).

I tried all manner of NDT meds to address my hypothyroidism. What I got was constant fluctuating hormone levels due to inconsistencies in the meds as evidenced via lab testing and unpleasant physical symptoms that adversely affected my quality of life for 10+ years. In my practice, I work with thyroid cases (but I am not a prescribing practitioner) and was used to seeing how poorly people felt on synthetic T4 only drugs like Synthroid, so I felt comfortable recommending they ask their doctor for NDT, which in many cases did help them.

But as time wore on and I continued to experience constant trouble with my thyroid levels and heard from my clients on NDT that they experienced heart palpitations, anxiety, and other unpleasant symptoms, I began delving more into the research and was furious with what I found: consistent NDT recalls, differences in potency from batch to batch, and so many inconsistencies with NDTs that explained why I was suffering for so many years.

Though I do feel much better after switching to synthetic thyroid replacement (it’s the same potency batch to batch!), T4 only was not right for me. And the adjustment process of switching from NDT to synthetic and finding the right doses took months of additional frustration. I ended up needing a customized dose of T4 with a bit of T3 that I get from a compounding pharmacy to feel optimal. I recommend working with a doctor who is willing to work with YOU and not just send you packing with a standard dose of Synthroid. You’ll likely have to be your best health advocate here and stay on top of testing your thyroid to see how you’re responding to your meds.

I’d love to hear from you: How did you find your optimal thyroid medication?

Thyroid Resources

Datis Kharrazian
Isabella Wentz, PharmD:The Thyroid Pharmacist
Stop the Thyroid Madness

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