From the Guidelines
Low free testosterone and gynaecomastia can result from various causes, including aging, obesity, certain medications, liver disease, kidney disease, and hormonal disorders like hypogonadism, with the most recent evidence suggesting that obesity-related decreases in testosterone are frequently attributable to low concentrations of sex hormone-binding globulin 1.
Causes of Low Free Testosterone and Gynaecomastia
The causes of low free testosterone and gynaecomastia are multifactorial and can include:
- Aging, with a gradual decline in serum total testosterone levels beginning in men in their mid-30s and continuing at an average rate of 1.6% per year 1
- Obesity, which can lead to low concentrations of sex hormone-binding globulin and increased aromatization of testosterone to estradiol in adipose tissue 1
- Certain medications, such as spironolactone, finasteride, antipsychotics, and some chemotherapy drugs
- Liver disease and kidney disease, which can disrupt hormone balance and lead to low testosterone and breast tissue growth in men
- Hormonal disorders like hypogonadism, which can be caused by pituitary tumors, hyperprolactinemia, and other conditions
Diagnosis and Treatment
A comprehensive hormone panel including testosterone (total and free), estradiol, prolactin, and luteinizing hormone is typically needed for proper diagnosis 1. Treatment depends on the underlying cause and may include:
- Lifestyle changes, such as weight loss, exercise, and reducing alcohol consumption
- Testosterone replacement therapy, typically 50-100mg weekly injections or daily transdermal applications of 50-100mg
- Medications like tamoxifen (10-20mg daily) or anastrozole (1mg daily) to address gynaecomastia
- Surgical intervention in established cases of gynaecomastia It's essential to identify and address the root cause rather than just treating symptoms, as low testosterone can impact energy levels, sexual function, bone density, and overall quality of life.
From the FDA Drug Label
Gynecomastia may develop and occasionally persists in patients being treated for hypogonadism. The causes of low free testosterone are not directly addressed in the label. The cause of gynaecomastia mentioned is treatment for hypogonadism 2.
From the Research
Causes of Low Free Testosterone
- Low free testosterone can be caused by various factors, including hypogonadism, which can be due to primary testicular failure or secondary to hypothalamic-pituitary dysfunction 3
- Nontumorous hyperestrogenism can also lead to male hypogonadism, characterized by low testosterone levels and elevated estrogen levels 4
- Certain medications, such as those used to treat HIV, antineoplastic agents, and other drugs, can also contribute to low free testosterone levels 5
Causes of Gynaecomastia
- Gynaecomastia can be caused by an imbalance of estrogen and testosterone levels, with an increased estrogen/testosterone ratio 6, 5
- Certain medications, such as those used to treat HIV, antineoplastic agents, and other drugs, can also contribute to the development of gynaecomastia 5
- Nontumorous hyperestrogenism can also lead to gynaecomastia, characterized by elevated estrogen levels and low testosterone levels 4
- Other factors, such as obesity, diabetes, and metabolic syndrome, can also contribute to the development of gynaecomastia 3
Relationship between Low Free Testosterone and Gynaecomastia
- Low free testosterone levels can contribute to the development of gynaecomastia, as it can lead to an imbalance of estrogen and testosterone levels 6, 4
- Gynaecomastia can also be a symptom of underlying hypogonadism, which can be characterized by low free testosterone levels 3
- Treatment of underlying hypogonadism and correction of estrogen and testosterone imbalances can help alleviate gynaecomastia symptoms 6, 7