Diurnal Testosterone Concentration

Inclusion criteria

Men with testosterone deficiency:

• Ability to read, write, and understand English
• Male sex at birth
• Age greater than or equal to 18
• Age less than 46
• Diagnosed with testosterone deficiency prior to visit 1
• Screening testosterone concentration of less than 350 ng/dL
• Willing and able to comply with the study protocol
• Willing to provide informed consent for this study
• No previous exposure to exogenous T unless off therapy for at least 4 weeks

Men without testosterone deficiency:

• Ability to read, write, and understand English
• Male sex at birth
• Age greater than or equal to 18
• Age less than 46
• Never diagnosed with testosterone deficiency
• Screening testosterone concentration of greater than 350 ng/dL
• Willing and able to comply with the study protocol
• Willing to provide informed consent for this study
• No previous exposure to exogenous T

Exclusion criteria

• Previous exposure to exogenous T, clomiphene citrate, or other Selective Estrogen Receptor Modulators, unless off therapy for at least 4 weeks
• Serious psychiatric disease or uncontrolled medical illness, as suspected from the history or clinical examination
• Used any sex hormones or steroidal anabolic drug supplements within 28 days before screening testosterone collection
• Incapable of giving informed consent or complying with the protocol