Have you lost your libido? Check your TSH and Free T4

Do you often feel tired, experience low libido, or notice unexplained mood swings? The issue might not just be your lifestyle—it could be linked to a small but powerful gland called the thyroid. The TSH and Free T4 blood tests are essential tools for evaluating the health and function of your thyroid gland, which plays a key role in regulating your energy levels, mood, and sexual function.In this article from Dalili Medical, we provide a comprehensive guide to understanding the TSH and Free T4 tests: what they are, why they are ordered, how to interpret the results, and how they relate to your sexual and overall health.

✅ What Are the TSH and Free T4 Tests?

1. TSH (Thyroid Stimulating Hormone)

This test measures the level of TSH, a hormone produced by the pituitary gland that stimulates the thyroid to produce T3 and T4 hormones, which regulate metabolism and body functions.

2. Free T4 (Free Thyroxine)

This measures the active (unbound) form of thyroxine (T4) circulating in the blood. It plays a direct role in regulating energy production, metabolism, and many organ functions.

❓ Why Are These Tests Ordered?

Doctors commonly order TSH and Free T4 tests when a patient presents with symptoms such as:

Persistent fatigue and low energy
Low libido or erectile dysfunction
Hair loss and dry skin
Unexplained weight gain or loss
Irregular menstrual cycles in women
Feeling too cold or too hot
Anxiety, depression, or sleep disturbances

⚖️ The Link Between Thyroid, Energy, and Sexual Function

The thyroid is a key regulator of metabolism. When it's underactive (hypothyroidism):

Metabolism slows down
Energy levels drop
Blood flow decreases
Libido and sexual hormone production decline (e.g., testosterone and estrogen)

In cases of overactive thyroid (hyperthyroidism), the body goes into overdrive, often leading to:

Anxiety and restlessness
Increased heart rate
Premature ejaculation or erectile problems
Irregular menstrual cycles

Normal Reference Ranges

Test	Normal Range
TSH	0.4 – 4.0 mIU/L
Free T4	0.8 – 1.8 ng/dL

⚠️ Reference values may vary slightly between laboratories. Always interpret your results with your doctor.

How to Interpret the Results

TSH High + Free T4 Low

Diagnosis: Hypothyroidism
Symptoms: Fatigue, weight gain, low libido, depression

TSH Low + Free T4 High

Diagnosis: Hyperthyroidism
Symptoms: Anxiety, rapid heartbeat, erectile dysfunction, premature ejaculation

TSH Low + Free T4 Low

Possible cause: Pituitary gland dysfunction (secondary hypothyroidism)

Thyroid Disorders and Sexual Health

In Men:

Reduced testosterone production
Erectile dysfunction or early ejaculation
Low sperm count and poor sperm quality

In Women:

Irregular periods or missed cycles
Ovulation problems and infertility
Vaginal dryness and low sexual desire

When Are Additional Tests Needed?

If thyroid dysfunction is suspected, doctors may recommend:

Free T3 Test – for a complete thyroid profile
Thyroid Antibodies (Anti-TPO, Anti-TG) – to assess autoimmune thyroid conditions
Thyroid Ultrasound – to check for nodules or structural issues
Sex hormone tests – such as FSH, LH, Prolactin, Testosterone

Is There Treatment for Thyroid Disorders?

Yes. Treatment depends on the type of dysfunction:

⬇️ For Hypothyroidism:

Levothyroxine is prescribed to replace the missing hormone

⬆️ For Hyperthyroidism:

Anti-thyroid medications (e.g., Carbimazole)
Radioactive iodine therapy
Surgery in selected cases

✳️ Regular monitoring of hormone levels is crucial to adjusting treatment effectively.

❓ Frequently Asked Questions

Does thyroid dysfunction affect erections?
Yes. Low thyroid function reduces testosterone and blood flow, leading to ED.

Can abnormal TSH cause weight gain?
Yes. Hypothyroidism slows metabolism, making weight gain more likely—even with a healthy diet.

Does thyroid affect fertility?
Yes. Thyroid hormones are vital for reproductive health in both men and women.

Is treatment lifelong?
In many cases, yes—especially for permanent hypothyroidism. But proper treatment under medical supervision ensures a normal life.

✅ Conclusion

TSH and Free T4 tests are essential for assessing thyroid function, which significantly impacts:

Energy
Focus
Weight regulation
Sexual health and fertility

If you're experiencing unexplained fatigue, mood changes, or sexual health concerns, don't hesitate to get tested. Early diagnosis leads to better outcomes and improved quality of life.