When you are on T4 and T3 thyroid medications, the debate of T3 vs T4 will always come up. Many thyroid patients on a T3 or T4 supplement are still left with thyroid symptoms. They are also left wondering what is still wrong with their thyroid after treatment. Here are 7 points you need to know about T3 and T4, their differences, supplementation, and treatment. Find out all you need to know about T3 vs T4 hormones and how they work best for thyroid management and treatment!
T3 vs T4 Differences, Treatment, and Supplementation
1. T3 vs T4
Our thyroid produces two thyroid hormones. You have T4, or thyroxine (inactivated thyroid hormone) and T3, or triiodothyronine (activated). This means it can go right to the cells ready for use. Every cell in our body has thyroid receptors where t3 can go. T4 needs to be converted into t3 in order for the cells to use it. Our body produces this hormone at a ratio of 93 percent for the inactivated T4 and 7 percent of the activated T3.
2. Difference Between T3 And T4
There are differences between T3 and T4 treatments with the different nature of each hormone. Your thyroxine (T4) are mostly produced by your thyroid but triiodothyronine (T3) is the conversion of T4. It actively plays a role in your cells’ metabolism. Not having enough of both thyroid hormones will slow your metabolism which is a symptom of hypothyroidism.
3. Levothyroxine Medication
One of the most common prescriptions given to thyroid patients is levothyroxine. It is a medication which introduces synthetic T4 hormones into your body and is considered a standard treatment for hypothyroidism. This is due to the fact where most of the T3 in the body were T4 hormones. It is only when the T4 comes into contact with other cells in the bloodstream that it converts into its more active form, T3.
4. Disadvantage of Levothyroxine
A study finds that levothyroxine-only treatment (i.e., Synthroid, Unithroid, Levoxyl, Eltroxin, Tirosint, etc.)… http://t.co/nMGmCU51
— Mary Shomon/Advocate (@ThyroidMary) May 22, 2012
Levothyroxine-only treatment such as Synthroid, Unithroid, Levoxyl, Eltroxin, and Tirosint cannot guarantee normal range thyroid lab results in athyreotic patients. Most patients treated with levothyroxine have higher levels of Free T4 and their Free T3 levels are much lower.
The T4 hormone is usually converted into T3 in the liver but not everyone can convert T4 into T3 efficiently. By only supplementing your bloodstream with T4, you are raising the levels of T4 in your body but not ensuring its conversion into T3.
5. T3-Only Treatments
— Mary Shomon/Advocate (@ThyroidMary) March 20, 2017
If T4-Only Medication doesn’t help, you can try thyroid hormone replacement drugs which will add to your T3 levels instead. The T3 hormone is more biologically active and works at the cellular level to help with the regulation of oxygen and energy throughout your body, including the cells, tissues, and glands.
6. Side Effects of High T3 Levels
Since T3 is an active hormone, having an increased amount of T3 can result in over-stimulatory effects, especially on heart rates. This makes this form of treatment a danger to people with a history of heart disease, heart irregularities, and the elderly.
T3-only treatments are not recommended for patients with heart or age-related issues. The heart itself is sensitive to thyroid hormones which is why a regulation of T3 levels is very important.
7. Combination of T3 and T4 Treatments
A study in 2009 shows, patients prefer treatment with a combination of both T3 and T4 medication as opposed to just focusing on thyroid hormone. The T4/T3 combination therapy including 20 mcg of the T3 daily was superior to levothyroxine-only treatment. Even when evaluating for a number of quality of life measurements, depression and anxiety scales, and patient preference.
T4 alone is not able to maintain normal circulating thyroid hormone levels in some patients. There are patients who will need medication that includes T3 as well. This is the same for T3-only treatments since a high level of T3 content can overstimulate you. For the most optimal thyroid treatment, it is better to combine both T4 and T3 medication. Studies show levothyroxine plus liothyronine treatment shows better improvement in mood, quality of life, and cognitive factors for patients with hypothyroidism.
Watch this video from DrJason Pickel to find out more about the effects of T3 and T4 levels to your body:
Knowing the difference between T3, T4, and thyroid stimulating hormone (TSH) is important if you have thyroiditis. It is also important if you suspect thyroid dysfunction or have thyroiditis symptoms. Now you know more about T3 vs T4 and how the thyroid hormones interact. Knowing how thyroid hormones work will help you during your visits to the doctor. You can ask the important questions, share your concerns, and work alongside your doctor for better thyroid hormone management!
Do you still experience thyroid symptoms despite following all your doctor’s advice? Share your experience with us in the comments section below!
Editor’s Note: This post was originally published on September 1, 2017 and has been updated for quality and relevancy.