Understanding Reverse T3 & Thyroid Dysfunction

Does it feel that despite the progress and endless efforts, you can't seem to get on top of your thyroid health in the way you want to? There's likely something that might have been overlooked for those still burdened by the slow and sluggish symptoms associated with hypothyroidism, despite medication. It's time to talk about reverse T3, as it's an essential piece of the puzzle, and if you're still struggling to resolve your thyroid issues, it's a good time to start to understand.

So what exactly is Reverse T3?

When we speak to the role of reverse T3 (rT3) in the body, it can be helpful to revisit some of the fundamentals of thyroid hormones. Remember how the thyroid, the small butterfly-shaped gland in your neck, is prompted to release T4 in response to the release of Thyroid Stimulating Hormone (TSH) from the pituitary gland? When T4 is released, it is converted into a different hormone (T3), predominantly in the liver, before being delivered to tissues in the body for use. T3 is the active form of the thyroid hormone, which is vital for our body to help maintain homeostasis (the perfect balance). It does this by supporting all metabolic processes within cells of the body, including the production of ATP (energy) by the mitochondria, regulating body temperature, heart rate and metabolism to create the perfect environment.

However, not all T4 is converted to T3. A small amount is converted to the inactive form, reverse T3 (rT3). It acts similarly to T3 and binds to the same cells as its active counterpart, but it doesn't initiate a response - meaning those necessary functions aren't supported. Now reverse T3 is not all bad. The body needs to produce a certain amount to ensure that there is not too much active T3 circulating; in this instance, you could consider reverse T3 your metabolic break. ​​But when the ratio between the two becomes unbalanced in favour of rT3, hypothyroidism and Hashimoto's can become exacerbated. This could be beneficial for someone with hyperthyroidism, as it can combat thyroid overactivity. But if you're struggling with a slow or sluggish thyroid, this could potentially be an issue.

What are the downfalls of Reverse T3? 

While this hormone is an important regulatory mechanism in homeostasis, rT3 can also contribute to hypothyroid symptoms when too much is produced. As these two types of T3 typically compete for the same receptor sites, an excess of rT3 can make it challenging for the active form to bind to receptors and be moved into the cell to carry out the necessary functions. This is why sometimes people may suffer from symptoms of hypothyroidism, despite tests indicating their T4 and T3 levels are within the optimal range. And for those already struggling with hypothyroidism, this may intensify the symptoms they are experiencing. So you can see why it's vital to test more than just the basic thyroid hormones and assess levels of rT3.

Oftentimes, rT3 levels increase alongside T3 levels, leading to an abundance of rT3 in the body for those struggling with thyroid dysfunction.

So what causes an increase in rT3? This can include:

• Prolonged elevated stress levels

• Elevated inflammation 

• Poor liver function 

• Infections 

• Excessive caffeine intake

• Deficiencies in nutrients needed for the body to convert T4 to T3, including B6, Selenium, and Zinc.

It is important also to remember that this is a naturally occurring result of the complexities of thyroid hormone production, even for those who don't have any thyroid concerns, and that production of reverse T3 is a normal bodily function. Only when the ratio of rT3:T3 tips in favour of rT3, it is crucial to assess what may be driving up this imbalance.

One of the most important things you can do when noticing any signs or symptoms of thyroid dysfunction is to work with a practitioner who can investigate comprehensive thyroid testing labs to address the root cause of these issues.

If you're interested in discovering more about your own levels of reverse T3, I offer a free 15-minute consultation where we can discuss your options.