The Connection Between Low Thyroid and Low Testosterone in Men

Integrative Wellness FX in Dallas, TX, specializes in helping men dealing with the dual challenges of low thyroid (also known as hypothyroidism) and low testosterone. Many men don’t realize that their low thyroid activity and low testosterone levels can be connected. In this article, we’re going to explain how these two conditions are related and how men can overcome these challenges to restore health and vitality.

The Endocrine Symphony: Thyroid and Testosterone Basics

Located in your neck, the thyroid gland produces hormones primarily known as thyroxine (T4) and triiodothyronine (T3). These hormones regulate metabolism, heart rate, energy production, and internal temperature. T4 is considered the storage form, while T3 is the active form that binds to cell receptors and influences many bodily processes.

Testosterone is produced mainly by the Leydig cells in the testes and is regulated by the hypothalamus-pituitary-testis axis. The hypothalamus releases GnRH (gonadotropin-releasing hormone), prompting the pituitary gland to release LH (luteinizing hormone), which stimulates the testes to produce testosterone. This hormone supports muscle mass, libido, mood, bone density, and overall vitality in men.

Molecular Cross-Talk: How Low Thyroid Impairs Testosterone

When thyroid hormones are low, the body enters a state of metabolic conservation. One of the first systems affected is the brain’s hypothalamic function, which may reduce GnRH output. This suppression impacts the entire testosterone production chain, leading to reduced LH and, ultimately, lower testosterone synthesis in the testes.

Low thyroid function also disrupts the production of sex hormone–binding globulin (SHBG), a liver-made protein that binds testosterone in the bloodstream. While lower SHBG levels may temporarily increase free testosterone levels, they typically coincide with overall hormonal imbalances and a reduction in total testosterone.

Another key disruption is enzymatic. The conversion of T4 to active T3 requires enzymes known as deiodinases, and these same thyroid hormones also impact the activity of 5α-reductase and aromatase, which are essential for metabolizing testosterone into other active or balanced forms. With low thyroid activity, these conversions become less efficient, causing hormonal imbalances, poor tissue response, and a cascade of secondary effects.

More importantly, thyroid hormones are central to mitochondrial function. Mitochondria are the energy-producing centers of cells, and testosterone production in the Leydig cells depends on adequate ATP energy. Without enough thyroid hormone, mitochondrial efficiency drops, resulting in less free testosterone being produced..

The Feedback Vortex: A Vicious Cycle

A man with low thyroid levels can develop low testosterone, and in turn, low testosterone can worsen thyroid function. This creates repeating cycles of worsening energy, mental fog, and reduced physical capacity. Symptoms compound and make diagnosis difficult if both systems aren’t evaluated together.

This feedback loop may look like this: low thyroid function leads to reduced stimulation of the hypothalamus and pituitary, lowering LH levels and testosterone production. Then, as testosterone declines, it worsens mood, energy, and metabolic rate, all of which can further depress thyroid function. The result is a downward spiral of hormonal dysfunction.

Symptoms Men May Experience

Because symptoms of low thyroid and low testosterone overlap, men often dismiss them or misattribute them to stress or aging. These include:

• Persistent fatigue or low stamina
• Difficulty losing weight or unexplained weight gain
• Low libido or erectile dysfunction
• Depressed mood or irritability
• Decreased muscle mass or physical strength
• Sensitivity to cold or consistently low body temperature
• Thinning hair or changes in skin texture

When these symptoms appear in clusters, it’s important to evaluate thyroid and testosterone levels together.

Diagnostic Workup: What We Assess at Integrative Wellness FX

At our Dallas clinic, we don’t just glance at your TSH and testosterone levels; we look deeper. Our functional medicine approach includes:

• A comprehensive thyroid panel, including TSH, Free T3, Free T4, Reverse T3, and thyroid antibodies (TPO and Tg).
• Full reproductive hormone analysis, including total and free testosterone, SHBG, LH, FSH, and estradiol.
• Metabolic and conversion markers, like DHEA-S, DHT, and vitamin D.
• Lifestyle-based assessments, such as basal body temperature and sleep quality.

This holistic lens helps us determine whether one hormone is dragging down the other, and where to intervene.

Treatment Strategies: Restoring Hormonal Harmony

When resolving low thyroid and testosterone, we often address the thyroid first. Many men experience a significant improvement in testosterone levels once optimal thyroid function is restored.

Thyroid support may include bioidentical hormone replacement using T4, T3, or a combination, depending on your unique physiology and how well your body converts T4 to T3. Nutritional strategies such as iodine, selenium, zinc, iron, and vitamin D effectively support thyroid hormone production and activation.

For testosterone, we use a stepwise approach. Lifestyle is foundational: strength training, sufficient sleep, stress reduction, and a diet rich in healthy fats, proteins, and micronutrients. These lifestyle changes can significantly boost testosterone levels naturally. If needed, we may explore bioidentical testosterone replacement, using topical, injectable, or subcutaneous methods, always carefully monitored to prevent imbalances with estrogen or DHT.

Take the Next Step

If you’re a man in Dallas or Fort Worth experiencing low energy, increased fatigue, and other forms of dysfunction, we encourage you to look deeper than addressing low testosterone alone. Let us help you get to the root of your health. 

At Integrative Wellness FX in Dallas, we consider your entire endocrine system to identify and treat the root cause. We also carefully examine the link between low thyroid and low testosterone and how they play off each other. 
Reach out to become a patient today and experience the difference for yourself.