Low thyroid and weight loss: 4 hidden reasons you’re still stuck

It’s well-known that poor thyroid function or hypothyroidism can trigger weight gain, along with other symptoms of a sluggish metabolism like fatigue, bloating, fluid retention, dry skin, and hair thinning.

That’s because having low levels of active thyroid hormone messes up your body’s energy regulation, causing you to burn less fuel and store more fat.

But what if you have all of these symptoms, including trouble losing fat, but your doctor says your thyroid is “normal?” Or what if you’re treating your hypothyroidism with medications, but you’re still not able to drop body fat?

You’re in luck, because in this article, I’m going to reveal four reasons that you’re still gaining weight because of hidden hypothyroid problems, and how to solve them using Functional Medicine.

One really quick note before we dive in - I go much more in-depth into all things thyroid in my Thyroid Deep Dive Tutorial.

This can be a game-changer especially if you’ve felt dismissed by your healthcare providers. To access the deep dive, join my VIP YouTube Membership - simply sign into your YouTube account and click the “Join” button to sign up.

Alright, the first reason that your weight gain may be caused by a hidden thyroid problem is that you’re relying on the wrong normal ranges for your thyroid labs.

Sometimes “normal” test results are fantastic news, but other times they’re a dead end, because if your thyroid lab testing comes back “within normal limits”, it can put the brakes on further help or testing from conventional providers.

And it can even lead to minimization or dismissal of your symptoms. It happens a lot!

In Functional Medicine, we don’t settle for “normal” when it comes to the thyroid - because “average” is not the same as “optimal.”

Many of the original “normal” lab values were determined by population studies done on “healthy” white males. So, if you happen to be a female, or non-white, you can imagine that these normal levels might not YOUR optimal levels - especially if you’re trying to lose body fat.

Also, it’s important to recognize that that insufficiency is possible without deficiency. In other words, you might have enough thyroid hormone to survive, but not to support the full, optimal functioning of your body.

My optimal ranges for thyroid markers are as follows:

If you fall outside that optimal range, your poor thyroid function may be impacting your ability to achieve and maintain a healthy body weight.

This brings us to our second reason - if you’re only measuring your TSH or Thyroid Stimulating Hormone to determine your thyroid function, you’re missing out.

And this is a bummer because most doctors rely on TSH to screen for hypothyroid - even though studies suggest that subclinical hypothyroidism can go undetected for years before elevations of TSH will show up on labs. I see it all the time.

So, if you’re struggling with weight loss resistance and you suspect your thyroid has something to do with it, it’s time to insist on a complete thyroid blood test including at minimum TSH, Free T4, Free T3, and Thyroid antibodies.

If your doctor can’t or won’t order these tests for you, consider ordering them yourself through my website - it’s a simple at-home testing kit and I’ll even help you interpret the results and come up with some strategies to address any imbalances that you find. We help folks all over the world access thyroid testing - so check it out HERE.

Once you have the full picture of your thyroid levels, you can assess the third reason that your weight gain may be caused by a hidden thyroid problem - poor thyroid hormone conversion.

When your pituitary starts cranking out TSH, it tells your thyroid gland to start making thyroxine (T4) as well as a little triiodothyronine (T3). T4, which represents 90% of your thyroid gland output, is inactive.

That means it can’t interact with the cells of your body to regulate your metabolism until it’s converted into the active form of thyroid hormone, T3.

Only once T4 is turned into T3 can it bind to regulation sites called receptors on your cells and make that metabolic magic happen. So, even if your thyroid is making plenty of T4 hormone to run your metabolism and burn fat, if it’s not converted to free T3, you could still be functionally hypothyroid.

What causes problems with thyroid conversion?

Unfortunately, a whole lot of factors including:

stress and high cortisol
fasting
certain medications
diabetes
low progesterone - which is common in perimenopause and menopause
pesticides
heavy metals
iodine excess
alcohol

Micronutrient insufficiencies like low iron, ferritin, B vitamins, Zinc, and Selenium can also cause poor conversion. We’ll talk about my favorite evidence-based strategies for improving the conversion of T4 to free T3 in a minute.

But first we need to talk about the fourth hidden thyroid problem that makes it tough to lose body fat - autoimmune hypothyroid, also known as Hashimoto’s.

Thyroid peroxidase antibodies and antithyroglobulin antibodies are often the first thing to show up when the thyroid is struggling - even though they’re often the last thing to be tested.

Research shows that these thyroid antibodies can be elevated for 10-15 YEARS before your TSH rises outside of the conventional “normal”. And this isn’t a rare problem - Hashimoto’s is the most common kind of thyroid problem.

What do these thyroid antibodies do to disrupt your metabolism and trigger low thyroid symptoms?

Well, they can block the effective binding of free T3 to the thyroid receptors on your cells, making it harder for your body to respond to thyroid signals.

They can damage your thyroid over time by creating inflammation in the glandular tissue, eventually lowering your capacity to make T4.

But even if your other thyroid levels are in the optimal range, significantly elevated thyroid antibodies are associated in the medical literature with anxiety, depression, OCD, infertility, brain fog, high cholesterol, and blood sugar problems that lead to weight loss resistance.

And these studies show that even if you’re actively treating your hypothyroid with medication, the presence of thyroid antibodies can still cause these symptoms.

So, given that there are multiple hidden reasons that your thyroid is contributing to your weight gain or weight loss resistance, what can you do about it?

The first thing to do is to get a complete thyroid panel - including TSH, Free T4, Free T3, and TPO antibodies.

And once you get your thyroid lab results, you’re going to compare your levels to my optimal ranges instead of settling for the lab’s "normal" range.

Reverse T3 and TPA antibodies can also be helpful, but most of the time I’m satisfied with the first four.

It’s important that you’re specific when you request thyroid testing, because otherwise your healthcare provider is probably going to order a TSH, or maybe T4.

But you need to see that free T3 number in order to figure out if you’re struggling with thyroid conversion. You’re welcome to order a test kit through my website - and if you do, I’ll help you interpret the results and come up with a plan. HERE is that link again.

The next thing to do is support thyroid conversion - some folks find that they feel best in the upper half of the optimal range for free T3. Here are a few strategies to improve your free T3 levels:

Replenish micronutrient levels like Vitamin E, selenium, magnesium, and zinc.

My favorite supplement for thyroid conversion optimizes all of these levels in one capsule - because it was designed specifically with conversion issues in mind. It also contains myo-inositol, which lowers thyroid antibodies.

AND it contains Rhodiola, an adaptogenic herb that promotes adrenal regulation, lowers cortisol, and protects the brain, specifically reducing symptoms like fatigue, anxiety, and depression. You can purchase this supplement through my Fullscript dispensary at a super nice discount HERE.

Low iron and ferritin levels can also cause poor thyroid conversion and function.

I’ve got lots of videos about low ferritin in my YouTube library because it’s so common and yet under-diagnosed and under-treated, so be sure to check those out HERE.

When it comes to lowering those pesky thyroid antibodies, the key is focusing on the gut.

Often, removing certain foods from your diet can help. Many people with Hashimotos also react to gluten and gluten-containing foods. A 2002 study found that 43 percent of people with Hashimoto’s showed activated mucosal T cell immunity, which is usually correlated with gluten sensitivity.

And the antibodies produced in celiac disease can cross-react with thyroid antibodies in a phenomenon known as molecular mimicry, amplifying inflammation and damage of the thyroid via autoimmunity.

Even if you don’t have celiac disease or gluten sensitivity, gluten can cause intestinal hyperpermeability also known as leaky gut, which contributes to elevated thyroid antibodies. I always recommend that folks with significantly elevated thyroid antibodies follow a gluten-free diet.

Another really helpful step is to assess and address other hormones that impact your thyroid function.

For example, testing and lowering cortisol levels can help prevent the conversion of T4 to reverse T3, which is an inactive form of T3 that can’t effectively bind to thyroid receptors.

And assessing reproductive hormones can identify sources of poor thyroid conversion - like low progesterone - or sources of chronic inflammation - like estrogen dominance.

The DUTCH complete hormone test is my favorite way to investigate hormones like these because blood testing, like thyroid blood testing, has giant normal ranges that aren’t particularly helpful or sensitive. Click HERE for more info about comprehensive hormone testing.

If you’re feeling frustrated, demoralized, or just plain stuck, it’s time for a deeper look into the health of your thyroid. I hope you found these insights and strategies helpful.

And don't forget - you’ll find even more in the Thyroid Deep Dive Tutorial - simply hit the "Join" button once you’ve signed into your YouTube account and sign up for access to all the videos in my exclusive member library.

If you’re interested in ordering comprehensive thyroid testing, check out my DIY Thyroid testing offer HERE.

For comprehensive hormone testing, click HERE.

If you would like to order my recommended supplements for thyroid support and healthy fat loss at a really nice discount, be sure to check those out in my Fullscript dispensary.