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Low T3 Symptoms and Causes

Are you feeling fatigued, experiencing unexplained weight gain, or struggling with mood swings? These could be signs of low T3 levels, a condition that affects your body’s metabolism and overall well-being. Low T3, or triiodothyronine, is a thyroid hormone essential for energy production, metabolism regulation, and overall health. When T3 levels dip below optimal ranges, various symptoms can manifest. In today’s article, we will explore the differnt symptoms of Low T3 as well as some of the root causes of Low T3.

Everything You Need To Know About Low T3 Symptoms and ROOT CausesImportant note

One thing to keep in mind as you read today’s article is that while on the surface it might seem that taking T3 is the best approach to restoring Low T3 levels, in most cases it is better to address the root caus and determine why your T3 levels are low in the first place. Dosing T3 thryoid hormone often leads to patients being overmedicated.

What Is T3 and Why Do I need to Know about it?

Triiodothyronine (T3) is one of the two main thyroid hormones produced by the thyroid gland, with the other being thyroxine (T4). T3 is the active form of thyroid hormone that plays a crucial role in regulating metabolism, energy production, body temperature, and many other essential functions in the body. It is more biologically active than T4 and has a more direct impact on cellular processes.

Testing for T3- Sadly…. Most doctors Never Test it!

Testing T3 levels can provide valuable information about thyroid function and help diagnose conditions Like Low T3. There are several biomarkers that are needed in order to properly assess Low T3.  These tests are:

1. Total T3 Test: This test measures the total amount of T3 in the blood, including both bound and unbound (free) forms. Total T3 levels can be influenced by factors such as thyroid-binding proteins and may not always reflect the active hormone available to the body.

2. Free T3 Test: Free T3 represents the unbound, biologically active form of T3 that is readily available to tissues and cells. Measuring free T3 levels provides a more accurate assessment of the active thyroid hormone status in the body.

3.Reverse T3 Test: Reverse T3 is an inactive form of T3 produced during times of stress or illness. Testing reverse T3 levels can help evaluate the balance between active and inactive thyroid hormones in the body.

T3 levels are often assessed alongside other thyroid function tests, such as T4, thyroid-stimulating hormone (TSH), and thyroid antibody tests, to provide a comprehensive picture of thyroid health.

To test T3 levels, a blood sample is typically collected from a vein in your arm and sent to a laboratory for analysis. It is essential to follow any specific preparation instructions provided by your healthcare provider, which may include fasting before the test or adjusting medications that could interfere with thyroid hormone levels.

Use this link to get a Comprehensive Thryoid Panel and consult 

whats Causing your Low T3 Thyroid Hormone Levels

10 Symptoms of Low T3 You Should Be Aware of

1. Fatigue: One of the hallmark symptoms of low T3 levels is persistent fatigue and low energy levels, despite getting enough rest. Individuals may find themselves struggling to stay awake during the day or feeling drained even after a good night’s sleep.

2.Weight Gain: Unexplained weight gain or difficulty losing weight is a common complaint among individuals with low T3 levels. The slowed metabolism associated with decreased T3 hormone levels can make it challenging to manage weight effectively.

3.Hair Loss: Changes in hair quality and quantity, such as thinning hair, brittle strands, or hair loss, can be indicative of low T3 levels. Hair follicles rely on adequate thyroid hormone levels for proper growth and maintenance.

4.Cold Intolerance: Feeling excessively cold, even in warm environments, or having a decreased tolerance to cold temperatures is often reported by individuals with low T3 levels. Thyroid hormones play a critical role in regulating body temperature.

5.Dry Skin: Low T3 levels can lead to dry, rough, or flaky skin, which may be accompanied by itchiness or irritation. Proper hydration and skincare regimens may offer some relief for these symptoms.

6.Muscle Weakness Weakness, aches, or cramps in the muscles can be a sign of low T3 levels impacting muscle function. Individuals may experience difficulty with physical activities or general weakness.

7.Depression: Low T3 levels have been linked to mood disturbances such as depression, anxiety, and irritability. Addressing thyroid hormone imbalances may help improve overall mental well-being.

8.Brain Fog: Cognitive symptoms like difficulty concentrating, memory problems, or mental fog are commonly reported by individuals with low T3 levels. Optimal thyroid function is crucial for maintaining cognitive abilities.

9.Constipation: Changes in gastrointestinal motility, such as constipation or irregular bowel movements, can occur with low T3 levels. Adequate hydration, dietary fiber, and physical activity may help alleviate these symptoms.

10.Menstrual Irregularities: Low T3 levels can disrupt hormonal balance in women, leading to menstrual irregularities like changes in cycle length, intensity, or frequency. Consulting a healthcare provider is recommended for managing these issues effectively.

Use this link to get a Comprehensive Thryoid Panel and consult 

Common Symptoms of Low T3_DrHagmeyer

Causes of Low T3

There can be many Root cause of Low T3. Lets review a few of these.

1.Nutrient Deficiencies

Nutrient deficiencies, particularly in essential nutrients like Iron, selenium and zinc, can impair the body’s ability to convert T4 (the inactive thyroid hormone) into the active T3 form. This can be a root cause of Low T3. Selenium, in particular, is crucial for the activity of the enzyme that converts T4 to T3. Inadequate levels of these nutrients can contribute to low T3 levels and thyroid hormone underconversion.

2.Chronic Stress

Another cause of Low T3 can be Chronic stress. Chronic stress can disrupt the hypothalamic-pituitary-thyroid (HPT) axis, which regulates the production and conversion of thyroid hormones. Prolonged stress can lead to imbalances in cortisol levels, which may affect the conversion of T4 to T3. Additionally, stress can impact the production of thyroid-stimulating hormone (TSH), which signals the thyroid gland to produce hormones.

Addressing these underlying factors through proper diagnosis, treatment, and lifestyle modifications can help restore optimal thyroid function and hormone balance. Consulting with a healthcare provider for personalized evaluation and management is essential in addressing low T3 levels and thyroid hormone underconversion effectively.


The liver is responsible for converting a significant portion of T4 to T3 through enzymatic processes. Liver dysfunction, such as liver disease or fatty liver, NAFLD, can impair this conversion process, leading to lower levels of T3 in the body. Reduced T3 levels due to impaired conversion can result in symptoms of hypothyroidism. If you have low T3 always think about the liver as a cause of Low T3.

4.Thyroid Hormone Binding Proteins.

The liver produces thyroid hormone-binding proteins that transport thyroid hormones, including T3 and T4, in the bloodstream. Any disruption in the production or function of these binding proteins can affect the distribution and availability of thyroid hormones to the body’s tissues.(*) Changes in binding protein levels can impact the bioavailability of T3, potentially leading to low T3 levels.

Use this link to get a Comprehensive Thryoid Panel and consult 


Certain medications, including those prescribed for liver conditions or other health issues, can interfere with thyroid hormone metabolism and clearance processes in the liver. Drug-induced liver damage or changes in enzyme activity can disrupt the conversion of T4 to T3, potentially being a cause of low T3.

Addressing these underlying factors through proper diagnosis, proper testing and treatment, lifestyle modifications can help restore optimal thyroid function and hormone balance. Consulting with a healthcare provider for personalized evaluation and management is essential in addressing low T3 levels and thyroid hormone underconversion effectively.

Next Steps

1.Take My Thyroid Quiz to Asssess your Thyroid Symptoms

2. Download My Free Thyroid Ebook 

3. Depending on Results of your Thyroid Quiz, Schedule a 15 min consult to see if my program is Right for you.

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  8. Use this link to get a Comprehensive Thryoid Panel and consult 


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