Testosterone prescriptions in the United States grew substantially over the past two decades before more recent guideline tightening and FDA labeling changes moderated the trend, a growth pattern that coincided with expanded direct-to-consumer marketing of "low T" clinics and symptom-based advertising — a trajectory that has prompted endocrinology and urology societies to clarify appropriate diagnostic criteria and candidate selection more explicitly.
The Diagnostic Criteria Require More Than Symptoms Alone
Clinical guidelines from the Endocrine Society and American Urological Association specify that a diagnosis of testosterone deficiency (hypogonadism) requires both consistent symptoms — reduced libido, fatigue, reduced muscle mass, among others — and confirmed low testosterone levels on at least two separate morning blood tests, since testosterone naturally follows a diurnal pattern and a single afternoon reading can appear falsely low. Some direct-to-consumer testosterone clinics have been criticized in professional literature for diagnosing and initiating treatment based on symptoms and a single test, or without adequately ruling out other causes of similar symptoms like sleep apnea, depression, or thyroid dysfunction.
Age-Related Decline Is Normal, Not Automatically Pathological
Testosterone levels naturally decline gradually with age in most men, and guidelines are explicit that age-related decline alone, without confirmed levels below the clinical reference range alongside genuine symptoms, does not constitute a diagnosis warranting treatment — a distinction that direct-to-consumer marketing framing "low T" as a common, treatable condition of aging has sometimes blurred for consumers evaluating whether therapy might benefit them.
Cardiovascular Risk Signal Prompted an FDA Labeling Change
Following several studies raising concern about potential cardiovascular risk associated with testosterone therapy, the FDA required labeling changes clarifying that testosterone products are approved specifically for men with hypogonadism due to identified medical conditions, not for age-related testosterone decline alone, and added labeling regarding a possible increased cardiovascular risk. Subsequent large-scale research, including a major dedicated cardiovascular safety trial, has provided some reassurance regarding cardiovascular risk in appropriately selected patients under medical supervision, though the FDA's more restrictive labeling regarding appropriate use criteria has remained in place.
Fertility Suppression Is an Underappreciated Side Effect
Exogenous testosterone therapy suppresses the body's natural hormonal signaling that drives sperm production, meaning testosterone therapy can significantly reduce or eliminate fertility during treatment — a consequence that is reversible in most cases after stopping therapy but that some patients, particularly younger men considering future fertility, are not adequately counseled about before starting treatment. This has become a specific point of emphasis in updated clinical guidance, particularly as testosterone therapy has expanded to a somewhat younger patient population through direct-to-consumer channels than its traditional older hypogonadal patient base.
Monitoring Requirements Extend Beyond the Initial Prescription
Patients on testosterone therapy require ongoing monitoring, including periodic hematocrit checks (testosterone can increase red blood cell production to levels that raise blood clot risk), prostate-specific monitoring given testosterone's role in prostate tissue, and periodic reassessment of whether continued therapy remains clinically appropriate — monitoring protocols that some lower-oversight direct-to-consumer clinics have been criticized for implementing less rigorously than guideline-concordant care requires.
Conclusion
Testosterone therapy is genuinely appropriate and beneficial for men with confirmed hypogonadism due to an identified medical condition, but guidelines are explicit that symptoms and age-related decline alone do not meet the diagnostic threshold, and ongoing monitoring for cardiovascular, hematologic, and prostate-related risk is an essential part of appropriate care. Practices managing hormone therapy rely on accurate lab supplies for the confirmatory and ongoing monitoring testing guidelines require.
