In a study of male pattern baldness 27 men used 1% testosterone propionate topically for 5 to 21 months with negative results. No patients demonstrated regrowth of hair. Approximately 50% of these patients subjectively noted decrease in rate of hair loss. This latter finding is difficult to evaluate, but is certainly not substantiated by scientific evidence.
Savin RC. The Ineffectiveness of Testosterone in Male Pattern Baldness. Arch Dermatol. 1968;98(5):512-514. doi:10.1001/archderm.1968.01610170072015