When the metabolism is running on low power
The thyroid gland is a small, butterfly-shaped organ located at the front of the neck, with a huge impact on almost all bodily functions. It produces the hormones thyroxine (T4) and triiodothyronine (T3) , which regulate metabolism, energy production, hormone balance, and mental performance. When this production is disrupted, it is called hypothyroidism (underactive thyroid) .
While women are often diagnosed early, male patients frequently remain undetected for a long time . Symptoms develop gradually, are dismissed as "signs of aging," or misinterpreted as burnout or depression. Yet, in men, the thyroid gland is closely linked to the male hormonal system, libido, and muscle metabolism.
What is hypothyroidism?
In hypothyroidism, the thyroid gland produces too little T4 and/or T3. This slows down the metabolism in cells, organs, muscles, and the brain. The causes can be varied:
- Autoimmune disease (especially Hashimoto's thyroiditis)
- Iodine deficiency , especially in regions with low iodine intake
- Thyroid surgery or radiation therapy
- Long-term stress or overtraining
- Dysregulation of the pituitary gland (central hypothyroidism)
- Medications , e.g., lithium, amiodarone, certain antidepressants
Especially in middle-aged men (35–60), hypothyroidism is often functional : The values are in the gray area, e.g. elevated TSH with still “normal” fT3, but symptoms are already clearly noticeable.
Typical symptoms in men
While women more often show classic symptoms such as weight gain or menstrual irregularities, hypothyroidism in men often manifests itself in areas such as:
- Loss of libido, erectile dysfunction
- Chronic fatigue and lack of motivation
- Difficulty concentrating (“brain fog”) and irritability
- Low mood and depressive disposition
- Sleep problems despite exhaustion
- Cold sensitivity, dry skin and hair loss
- Performance decline during training and poor recovery
Another warning sign: The feeling of being “mentally beside oneself”, avoiding decisions or constantly running in energy-saving mode.
relationship with testosterone
The thyroid gland and testosterone influence each other . A deficiency in thyroid hormones can:
- Inhibit the release of LH (luteinizing hormone) → testosterone decreases
- Increase sex hormone-binding globulin (SHBG) levels → less free testosterone
- Slowing down liver function → impaired hormone utilization
- Reduce emotional sensitivity and sexual desire
Conversely, a testosterone deficiency combined with suboptimal thyroid function can lead to an intensification of symptoms , especially in the areas of libido, sleep, cognitive clarity and drive.
Diagnostics: Which values are relevant?
A single TSH value is not sufficient for a comprehensive assessment of thyroid function. A meaningful analysis includes at least:
- TSH (thyroid stimulating hormone)
- Free T4 (fT4)
- Free T3 (fT3)
- TPO antibodies (in suspected Hashimoto's disease)
- Additionally: Cortisol, testosterone, SHBG, ferritin, vitamin D, iodine status
In functional hypothyroidism, a slightly elevated TSH level is often observed alongside a low-normal fT3 level. Nevertheless, symptoms are noticeable, and optimization can be beneficial.
What can a man do?
Nutrition & Micronutrients
- Iodine-rich foods (e.g. seaweed, seafood, iodized salt)
- Selenium (e.g., Brazil nuts, legumes) for T4-to-T3 conversion
- Zinc and iron support thyroid enzyme activity
- Vitamin D has a regulating effect in autoimmune hypothyroidism
lifestyle
- Reduce chronic stress , as cortisol can inhibit the thyroid gland.
- Strength and endurance training should be moderate , not excessive.
- Prioritize sleep , especially deep sleep phases for hormone regeneration.
- Avoid radical diets; a constant calorie deficit can suppress the thyroid gland.
Medical
- In cases of clinical hypothyroidism: substitution with levothyroxine (T4)
- Possibly combination therapy with T3 (e.g., in case of conversion disorder)
- Regular laboratory monitoring and individual dose adjustment
- For Hashimoto's: stabilize the autoimmune component through diet and lifestyle
Conclusion
The thyroid gland regulates your metabolism and hormonal balance . In men, an underactive thyroid often goes undetected for too long, impacting energy levels, libido, mood, and physical performance. However, targeted diagnostics and individualized therapy can make a significant difference.
If you're constantly tired, irritable, or lacking in energy, despite "normal" blood test results, your thyroid could be a key factor. A precise hormone check will provide clarity and reveal concrete next steps for sustainable optimization.
