Hypothyroidism Testosterone in Females: Impact on Health

Hypothyroidism can influence various hormonal pathways, including testosterone regulation in females. While often associated with male physiology, testosterone plays a crucial role in women’s health, affecting muscle mass, mood, energy levels, and reproductive function. Disruptions in thyroid hormones may contribute to imbalances, leading to noticeable symptoms and health concerns.

Understanding how hypothyroidism affects testosterone levels in women is essential for recognizing potential health implications and seeking appropriate medical guidance.

Thyroid Function And Hormonal Balance

The thyroid gland regulates metabolism, energy production, and overall endocrine function by producing thyroxine (T4) and triiodothyronine (T3). These hormones influence nearly every organ system, including the reproductive and adrenal glands. In females, they interact with the hypothalamic-pituitary-gonadal (HPG) axis, which governs sex hormone production, including testosterone. When thyroid function is impaired, disruptions in this axis can alter androgen levels, affecting muscle maintenance, mood stability, and libido.

One key mechanism is thyroid hormones’ impact on sex hormone-binding globulin (SHBG), a glycoprotein that binds to testosterone and regulates its bioavailability. Reduced thyroid hormone levels are associated with decreased SHBG production in the liver, leading to increased free testosterone in some cases. Conversely, prolonged hypothyroidism can suppress ovarian and adrenal androgen production, potentially lowering overall testosterone levels.

Thyroid dysfunction also influences steroidogenesis, the process of hormone synthesis. The conversion of cholesterol into pregnenolone, a precursor for testosterone, is regulated by thyroid hormones. A deficiency in T3 can impair this process, reducing androgen output from the ovaries and adrenal glands. Additionally, hypothyroidism alters luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion, further disrupting ovarian function and testosterone production. Research published in the Journal of Clinical Endocrinology & Metabolism highlights that untreated hypothyroidism often leads to androgen irregularities, reinforcing the intricate relationship between thyroid activity and sex hormone regulation.

Mechanisms Influencing Testosterone

The regulation of testosterone in females with hypothyroidism stems from disruptions in thyroid hormone activity. The thyroid modulates the hypothalamic-pituitary-adrenal (HPA) and HPG axes, which govern androgen synthesis and secretion. When thyroid function declines, these regulatory circuits become dysregulated, altering androgen production.

Dysfunction in the HPG axis is particularly significant because LH and FSH are directly involved in ovarian steroidogenesis. Hypothyroidism can suppress gonadotropin-releasing hormone (GnRH) pulsatility, reducing LH and FSH secretion. This affects ovarian theca cells, which rely on LH stimulation to produce androgens, including testosterone. The resulting decrease in ovarian androgen synthesis can lower circulating testosterone levels. However, in some cases, reduced SHBG in hypothyroid states may lead to higher free testosterone levels despite lower total testosterone.

Beyond the ovaries, the adrenal glands contribute significantly to circulating androgens. Hypothyroidism impairs adrenal steroidogenesis by affecting adrenocorticotropic hormone (ACTH) regulation and enzymatic activity. Reduced thyroid hormone availability downregulates enzymes necessary for androgen synthesis, such as 17α-hydroxylase and 17,20-lyase. A study in The Journal of Endocrinology found that women with hypothyroidism often have lower dehydroepiandrosterone sulfate (DHEA-S) levels, indicating diminished adrenal androgen output.

Thyroid dysfunction also affects peripheral androgen metabolism. The enzyme 5α-reductase, responsible for converting testosterone into dihydrotestosterone (DHT), is influenced by thyroid hormones. Reduced thyroid function may decrease enzymatic activity, altering androgenic effects in tissues such as the skin, muscles, and reproductive organs. This could explain why some women with hypothyroidism experience symptoms of androgen deficiency, including reduced muscle strength and low libido, despite normal or slightly elevated free testosterone levels.

Indicators Of Imbalance In Women

Testosterone fluctuations in hypothyroid women can affect both physical health and overall well-being. A decline in energy levels is often one of the earliest signs, as testosterone helps sustain stamina and reduce fatigue. Many women experience persistent tiredness, even after adequate rest. This exhaustion is compounded by the metabolic slowdown caused by hypothyroidism.

Changes in muscle composition and strength are another common indicator. Testosterone contributes to muscle maintenance, and a deficiency may lead to decreased muscle mass and difficulty building strength. Some women report feeling physically weaker or noticing a softer appearance in previously toned areas. This decline in muscle integrity can also influence metabolism, contributing to gradual weight gain.

Mood disturbances further highlight the connection between hormonal balance and mental health. Testosterone influences neurotransmitter activity, particularly dopamine and serotonin, which regulate mood and motivation. Women with lower testosterone levels may experience depression, irritability, or a general lack of enthusiasm. Cognitive symptoms such as brain fog, difficulty concentrating, and memory lapses can also emerge, affecting daily responsibilities.

Sexual health is another area where imbalances become evident. Low testosterone can diminish libido and sexual response, leading to a reduced interest in intimacy or difficulty experiencing arousal. Some women also report changes in sensitivity, affecting overall satisfaction. These shifts can have psychological and relational consequences, making it important to address hormonal imbalances when assessing changes in sexual well-being.

Interaction With Other Hormones

Testosterone in females does not function in isolation; its regulation is influenced by other hormones governing metabolism, reproduction, and endocrine balance. Estradiol, the primary form of estrogen in premenopausal women, shares a dynamic relationship with testosterone, as both originate from the androgen precursor androstenedione. The enzyme aromatase converts testosterone into estradiol, meaning fluctuations in testosterone can directly influence estrogen levels. Disruptions in androgen production due to hypothyroidism may affect estrogen synthesis, leading to menstrual irregularities and reproductive changes.

Cortisol, the primary stress hormone, further complicates this hormonal interplay. Chronic hypothyroidism can elevate cortisol levels by increasing hypothalamic-pituitary-adrenal (HPA) axis activity. Excess cortisol competes with testosterone for receptor binding and suppresses androgen production by inhibiting gonadotropin secretion. This imbalance can exacerbate fatigue, mood instability, and decreased libido, making it difficult to distinguish whether symptoms stem from thyroid dysfunction, androgen deficiency, or prolonged stress exposure.

Considerations For Reproductive Health

Testosterone imbalances in women with hypothyroidism can impact reproductive health, affecting menstrual regularity, ovarian function, and fertility. Since testosterone plays a role in follicular development and ovarian steroidogenesis, disruptions in its levels may contribute to reproductive challenges.

Menstrual irregularities are common in women with hypothyroidism-related hormonal imbalances. Low testosterone, often seen in prolonged hypothyroidism, can contribute to oligomenorrhea (infrequent periods) or amenorrhea (absence of menstruation) due to impaired ovarian function. Conversely, if free testosterone levels rise due to reduced SHBG, symptoms resembling polycystic ovary syndrome (PCOS) may develop, including anovulatory cycles and increased androgenic effects such as hirsutism. These imbalances can also affect egg quality and ovulatory consistency, making conception more difficult. Treating thyroid dysfunction may help restore hormonal equilibrium and improve reproductive outcomes.

Fertility considerations extend beyond ovulation, as testosterone also plays a role in uterine receptivity and early pregnancy maintenance. Research in Human Reproduction Update suggests that optimal androgen levels support endometrial function, aiding embryo implantation. Insufficient testosterone, particularly in the presence of hypothyroidism, may compromise this process, increasing the risk of early pregnancy loss. Women experiencing recurrent miscarriages or difficulty conceiving may benefit from a comprehensive hormonal evaluation, including thyroid function and androgen levels. Proper management of thyroid disorders, potentially alongside androgen modulation, can enhance reproductive success.

Laboratory Evaluations

Assessing testosterone levels in women with hypothyroidism requires a thorough laboratory evaluation, considering both total and free testosterone alongside related biomarkers. Since testosterone fluctuations can be subtle and influenced by multiple factors, a targeted approach is necessary to distinguish primary androgen imbalances from secondary effects of thyroid dysfunction.

Total testosterone measurement provides an overview of androgen production, but free testosterone levels are often more relevant in hypothyroidism due to SHBG alterations. A comprehensive assessment should include SHBG levels to determine bioavailable testosterone. Evaluating adrenal-derived androgens such as dehydroepiandrosterone sulfate (DHEA-S) and androstenedione can help clarify whether testosterone changes originate from the ovaries or adrenal glands. Given the influence of thyroid hormones on gonadotropins, measuring luteinizing hormone (LH) and follicle-stimulating hormone (FSH) provides further insight into ovarian function and androgen regulation.

Thyroid function tests, including thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), should be conducted alongside androgen testing to establish the broader endocrine context. Elevated TSH with low FT4 and FT3 confirms hypothyroidism, which may contribute to testosterone fluctuations. In cases where symptoms suggest androgen excess or deficiency, additional tests such as 5α-reductase activity markers or cortisol levels may be warranted. Proper laboratory analysis allows for a precise diagnosis and facilitates the development of an effective treatment strategy to restore hormonal balance.