Erythrocytosis Following Testosterone Therapy

Area of Science:

• Endocrinology
• Hematology
• Pharmacology

Background:

• Testosterone therapy (TTh) is increasingly prescribed for androgen deficiency, offering benefits for mood, libido, and body composition.
• A significant side effect of TTh is erythrocytosis, characterized by an elevated red blood cell count.

Purpose of the Study:

• To review the literature on testosterone-induced erythrocytosis and polycythemia.
• To explore potential mechanisms, formulation effects, and thromboembolic risks associated with TTh.

Main Methods:

• A comprehensive literature review was conducted using PubMed.
• Searched articles focused on testosterone therapy, erythrocytosis, and polycythemia.

Main Results:

• Short-acting injectable testosterone formulations are linked to a higher incidence of erythrocytosis.
• Potential mechanisms include hepcidin, iron metabolism, erythropoietin, bone marrow stimulation, and genetic factors.
• Increased blood viscosity may elevate risks for vascular complications, though evidence is limited.

Conclusions:

• Injectable testosterone formulations pose a greater risk for erythrocytosis.
• The precise pathophysiology and thromboembolic implications of testosterone-induced erythrocytosis require further investigation.
• Emerging data suggest a potential increased risk of cardiovascular events.