Testosterone Replacement Therapy (TRT) treats hypogonadism, a condition defined by consistently low testosterone levels combined with symptoms like fatigue, decreased libido, or loss of muscle mass. Family doctors, or primary care physicians, are authorized to prescribe testosterone and often serve as the first point of contact for men concerned about “low T.” Managing uncomplicated age-related testosterone decline is within the scope of a family physician’s practice.
Authority of a Family Physician to Initiate Treatment
A family physician is qualified to initiate and manage Testosterone Replacement Therapy for patients with clear symptoms and documented low testosterone levels. More than half of all testosterone prescriptions in the United States are written by primary care physicians, reflecting their common role in this area of care. This prescribing authority is standard for licensed medical doctors (MDs) and doctors of osteopathy (DOs), as well as many nurse practitioners and physician assistants, depending on state regulations.
Family doctors often manage late-onset hypogonadism, which is the age-related decline in testosterone production not caused by a specific underlying disease. These cases are considered less complicated and do not typically require specialist involvement. Since testosterone is a Schedule III controlled substance, family physicians must adhere to federal regulations regarding documentation, refills, and prescription validity.
Standard Diagnostic Protocols for Low Testosterone
The diagnosis of low testosterone requires both clinical symptoms and laboratory confirmation; a patient must have both to receive treatment. Symptoms such as low energy, reduced sexual desire, depressed mood, and decreased muscle mass prompt the initial investigation. Laboratory diagnosis requires measuring the total serum testosterone level on at least two separate occasions.
The timing of the blood draw is crucial, as testosterone levels naturally fluctuate throughout the day. Blood samples must be taken in the early morning, typically between 8:00 AM and 10:00 AM, when testosterone levels are highest. A total testosterone level below 300 nanograms per deciliter (ng/dL) on two separate morning measurements is the standard threshold used to define low testosterone.
If the total testosterone level is borderline, a family doctor may order additional tests, such as free or bioavailable testosterone, for a more accurate picture of the usable hormone. To determine the cause of the deficiency, the physician will also measure Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH). These gonadotropins help categorize the condition as primary hypogonadism, stemming from a problem in the testes, or secondary hypogonadism, indicating an issue with the pituitary gland or hypothalamus.
When a Referral to a Specialist is Required
While family physicians manage straightforward cases, certain complexities require a referral to a specialist, such as an endocrinologist or urologist. Highly abnormal initial lab results, particularly extremely low testosterone paired with low or low-normal LH and FSH, may suggest a pituitary gland issue requiring specialized evaluation. Measuring serum prolactin is performed in these cases, and persistently elevated prolactin levels may indicate a pituitary adenoma, prompting a referral.
Patients with a history of prostate cancer, severe untreated sleep apnea, or unmanaged congestive heart failure should not begin TRT. The family physician will refer them for specialist clearance before considering treatment. If a patient is experiencing fertility concerns, a urologist or reproductive endocrinologist is better equipped to manage the balance between TRT and sperm production, as supplementation can halt the body’s natural production. Complex cases of primary hypogonadism with an unknown cause or patients who do not respond to initial treatment also warrant specialist consultation.
Required Monitoring and Follow-Up Care
Once a patient begins TRT, consistent monitoring is required to ensure the treatment is effective and safe. During the first year of therapy, follow-up lab work is typically performed every three to six months. This confirms that testosterone levels are within the target therapeutic range, often between 400 and 700 ng/dL. The frequency may be reduced to annually after the patient’s levels stabilize.
A major focus of ongoing lab work is monitoring the complete blood count, specifically hematocrit and hemoglobin levels. Testosterone stimulates the production of red blood cells. An excessive increase, known as erythrocytosis, can thicken the blood and increase the risk of clotting. If the hematocrit rises above 54%, the family doctor may recommend reducing the dosage or therapeutic phlebotomy to remove blood.
For men over 40, monitoring prostate health is another component of follow-up care, involving checking the Prostate-Specific Antigen (PSA) level. A significant rise in PSA, defined as an increase of more than 1.4 ng/mL within a year, should prompt a referral to a urologist. The family doctor also assesses the patient’s symptoms during these visits to ensure the treatment is improving their quality of life, adjusting the dosage based on lab results and reported well-being.