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The thyroid gland, situated at the base of the neck, is a highly complex gland that helps control the metabolism of every cell in the body. When it is not functioning optimally, it can throw off every organ system. People who have an underactive thyroid do not produce enough thyroid hormone, so they cannot support their metabolic needs. Thus, they often need thyroid hormone replacement medications to improve their overall health. Ahead, a comprehensive overview of T3 thyroid medication and when it can be helpful for people with hypothyroidism.
The thyroid gland produces hormones that help regulate your metabolism. Specifically, they help control your metabolic rate through influencing systems like your heart rate, blood pressure, body temperate, muscle function, bone health, digestion, and brain development. So, when you think about it, the thyroid influences virtually every system in your body.
Thyroid hormone production, secretion, and distribution throughout the body is a highly complex process. If something throws this system out of balance, it can have systemwide effects.
The primary hormone in this complex process is thyroid-stimulating hormone (TSH). TSH is released by the pituitary gland and helps "stimulate" the thyroid gland to make more hormones when the body needs it. Thus, if thyroid hormones are low in your blood, the pituitary will release more TSH to increase production. Similarly, too much thyroid hormone signals the pituitary to reduce the amount of TSH so that it tells the thyroid to slow down on how much it is producing and secreting,
Making thyroid hormones
The thyroid produces two thyroid hormones: thyroxine (T4) and triiodothyronine (T3). The body needs iodine from the diet to make these two hormones. Before iodized salt was readily available, many people suffered from goiters because the thyroid had to work overtime to supply the body with enough thyroid hormone to support metabolic needs.
When the thyroid is working normally, it produces about 80% T4 and 20% T3. While T4 is far more abundant, it is more of a storage molecule, whereas T3 is more active and potent at the cellular level. Indeed, T3 is what helps deliver oxygen and energy to your cells.
When T4 and T3 are too low in the body, a person has hypothyroidism (underactive thyroid). In this condition, the body does not produce enough thyroid hormone. On the contrary, when these two hormones are high, it can indicate that a person has hyperthyroidism (overactive thyroid).
People who have hypothyroidism typically need medication to increase their thyroid hormone levels. Thyroid hormone replacement medication serves to do just that: replace thyroid hormone in your body by mimicking the actions of your hormones.
One of the most common thyroid medications is T4 because it has a long life span. People with hypothyroidism can still convert T4 into T3, the usable form of the hormone. Thus, most people take a T4 medication like levothyroxine. Yet, this therapy isn't for everyone, and some people do combination therapy with T3 or occasionally use T3 solo.
Like T4, T3 medication serves to increase T3 levels in your bloodstream. However, T3 has a shorter lifespan than T4, meaning that you have high levels of T3 for a short period, and then your levels can fall rapidly. On the contrary, T4 levels are more steady, so people do not need to take this medication as often.
Some people find adding a T3 thyroid medication preferable if they have not had success taking T4 on its own or are still struggling with unresolved thyroid symptoms. While T4 is the first line of treatment, it is not for everyone, and many people may benefit from the addition of T3 in their system.
Also, some people may argue that taking T3 is better because it is the usable form of the hormone and can take out the added step of having to convert T4 to T3. Yet, having an underactive thyroid does not mean you cannot make T3 out of synthetic T4.
Factors that affect T4 to T3 conversion
T4 needs to convert into the active thyroid hormone triiodothyronine (T3) for the body to use it. Not being able to convert T4 into T3 adequately can leave you hypothyroid and not optimally medicated. Poor T4 to T3 conversion can occur even if your TSH levels appear to be normal.
Some factors that may affect T4 to T3 conversion include:
- Poor diet
- Poor sleep
- Some medications
- Chronic inflammation
- Low selenium
- Zinc deficiency
- Kidney disease
- Liver damage
Understanding the root cause is vital for treating your thyroid condition and optimizing your T4 to T3 conversation.
Like any medication, there are side effects to taking T3 medication. People considering this medication should know that:
- T3 medications like Cytomel© need to be taken several times a day for levels to remain steady. Even with consistent dosings, hormone levels are challenging to control.
- T3 levels will surge shortly after taking synthetic T3 medications, leading to unpleasant side effects that mimic hyperthyroidism (rapid heart rate, anxiety, and sleep issues).
- T3 thyroid medications may cause bone complications because it stimulates bone resorption.
Synthetic T3 medication also takes away the body's need to control the conversation of T4 to T3 based on what the body needs at specific times. Therefore, it can be harder to manage metabolic needs when the body is not "in control."
Response rates vary between people. Some patients find they can feel the effects of their T3 medication immediately, whereas others require several weeks. Make sure you follow your doctor's orders on how to take your medication, when to take it, and when to adjust dosages. You may be required to do several blood tests until you are on the correct dose of medication.
Most providers do not prescribe T3 very often (if at all). Part of the reason many providers do not prescribe it is because they do not have specialized training in using other medications besides T4 for hypothyroid care.
However, T3 may be beneficial for some people. Working with a thyroid doctor proficient in using various treatments for hypothyroidism is essential to having the best thyroid care possible.
At Paloma Health, we believe the best thyroid medication is the one that is the safest and most effective for each person. There is plenty of data to support using T4 in most hypothyroid patients. However, there are circumstances where a combination of T4 and T3, or T3 alone, may be best for a person with hypothyroidism or Hashimoto's. Our trusted thyroid doctors will consider all options for creating the most comprehensive thyroid treatment plan for you.