What is TSH? What it says about the health of your thyroid gland (Thyroid-Stimulating Hormone)

Do you sometimes feel tired? Or do you feel like you're losing weight no matter how much you eat, or gaining weight even when you eat a little? Maybe you just feel irritable and anxious. Sometimes behind these things is a small but very important "boss" in our body. We call him the thyroid gland. So today we are going to talk about TSH, one of the main hormones that controls the work of the thyroid gland.

Simply put, what is TSH?

Although the name TSH sounds a bit scientific, its meaning is very simple. TSH stands for Thyroid-Stimulating Hormone . In Sinhala, it means "thyroid stimulating hormone". This is like a manager in an office. His job is to give orders to the "employee" called the thyroid gland to work.

This TSH hormone is produced in our body by a small gland about the size of a pea located under the brain. We call it the pituitary gland. This pituitary gland is the main controller of many other hormones in our body.

So, after the pituitary gland releases the TSH hormone into the bloodstream, it goes directly to the thyroid gland, which is a butterfly-shaped gland located under the skin at the front of our neck. Based on the message from TSH, the thyroid gland produces and releases two of its own hormones, thyroxine (T4) and triiodothyronine (T3), into the bloodstream.

So why are these T3 and T4 hormones so important to us?

These two hormones control our body's metabolic rate. Simply put, these two hormones determine the rate at which the food we eat is converted into energy and the body uses that energy. Not only that, but they also do many other very important jobs.

• Heart function and digestive system function are maintained properly.
• Helps control our muscles .
• Essential for brain development (especially in young children).
• Helps maintain bone strength .

Imagine, all of this is controlled by a wonderful coordination between the "Big Manager" in the brain (the hypothalamus), the "Manager" below him (the pituitary gland), and the "Servant" (the thyroid gland).

How is this TSH level controlled inside the body?

This is like the thermostat in our home AC. This system works very automatically, very intelligently. We call this a "feedback loop."

1. First step: First, a hormone called TRH (Thyrotropin-releasing hormone) is released from the hypothalamus in the brain. This is the first signal. It's like the "Big Manager" calling his "Manager" and telling him to "start working."

2. Second step:After receiving this TRH message, the pituitary gland (Manager) releases the TSH hormone into the bloodstream.

3. Step Three: The TSH hormone tells the thyroid gland (the worker) to "work, make T3 and T4." Accordingly, the thyroid gland makes T3 and T4 hormones and releases them into the blood.

4. The final step (Feedback): Now that the T3 and T4 hormone levels in the blood have reached the required level, it sends a signal to the brain, saying, "Okay, now there are enough hormones, stop sending TSH." When the pituitary gland receives that message, it reduces the release of TSH. It's like the compressor of an AC turns off when the room gets cold.

What is a normal TSH level?

TSH levels change with age. They can also change during pregnancy. And since these values ​​can vary slightly from one lab to another, it's important to look at the "normal range" on your report. But in general, normal TSH levels for a healthy person are as follows.

TSH levels during pregnancy

Healthy levels of thyroid hormones in the mother during pregnancy are essential for the healthy development of the baby's brain and body. TSH levels change during this time.

• First trimester: 0.18 – 2.99 (uIU/mL)
• Second trimester: 0.11 – 3.98 (uIU/mL)
• Third trimester: 0.48 – 4.71 (uIU/mL)

What happens if TSH levels decrease? (Hyperthyroidism)

If your TSH level is lower than normal, it often means that your thyroid gland is working too hard . We call this condition Hyperthyroidism .

Imagine that the "worker" (thyroid gland) we talked about earlier works alone without any control, without the manager's orders, and produces more T3 and T4 hormones than necessary. Then the T3 and T4 levels in the blood increase excessively. Seeing this, the "Manager" (pituitary gland) stops sending TSH almost completely. It seems to think, "The worker is working anyway, there's no point in me shouting." Therefore, the TSH level decreases. Conditions such as ``Graves' disease'' and thyroid nodules can cause this.

If you have these symptoms, it is important to see your doctor immediately for advice. This condition can be treated and managed well.

What happens if TSH levels increase? (Hypothyroidism)

If your TSH level is higher than normal, it means your thyroid gland is not working as well as it should . We call this condition Hypothyroidism .

What happens in this case is that the "worker" (thyroid gland) is very lazy. It does not produce enough T3 and T4 hormones. Then the T3 and T4 levels in the blood decrease. Knowing this, the "Manager" (pituitary gland) gets worried and sends more TSH messages to the "worker" to work.It's like talking to a lazy person to wake them up. This causes the TSH level in the blood to rise excessively. The main cause of this is an autoimmune disease called `(Hashimoto's disease)`.

These symptoms often develop gradually. So if you are experiencing these symptoms, it is important to talk to your doctor about them. This condition can also be very successfully controlled with medication.

Should I be worried if the TSH report is abnormal?

Absolutely not. Just because your TSH report is outside the normal range doesn't mean you have a disease 100%. Your doctor will be looking at many other factors when reviewing this report.

• Your age: People over 80 years old may have slightly elevated TSH levels. It is not always a sign of illness.
• Pregnancy: As we discussed earlier, TSH levels naturally change during pregnancy.
• Other serious illnesses: Other serious illnesses unrelated to the thyroid gland (e.g., a severe infection) can temporarily lower TSH levels.
• Other thyroid tests: The doctor comes to a final conclusion by comparing the results with other tests, such as not only TSH, but also Free T4 and Thyroid antibodies.

Most of the time, an abnormal TSH level indicates a change in the functioning of the thyroid gland. The good news is that both of these conditions (Hyperthyroidism and Hypothyroidism) can be very successfully controlled with proper treatment and medication, allowing you to live a healthy, normal life.