Patient case (clinical description): A 19-year-old male came to clinic with some sexual concern.  He recently engaged in a relationship and is worried about the satisfaction of his girlfriend. He has a "baby face" according to his girlfriend's statement and he is not as muscular as his classmates.  On physical examination, there is some pubic hair and poorly developed secondary sexual characteristics. He is unable to detect coffee smell during the examination, but the visual acuity is normal. Ultrasound reveals the testes volume of 1-2 ml. The hormonal evaluation showed serum testosterone level of 65 ng/dL with low levels of GnRH.

Patient's own account: I'm 19 years old guy and I just went to see a doctor at the clinic after I just got with my girlfriend. I'm kinda worried because she thinks that I have a baby face and to be honest, I'm way less muscular than my classmates. I don't have much hair down there, and yes, I don't have that macho look. The doctor made me smell some coffee and I couldn't smell anything special. I also had some eyesight checkups and the doctor told me everything was normal. I got my test results back and it says: testes volume is 1-2 ml and serum testosterone level of 65 ng/dL with low GnRH levels.

Clinical trial: Trial of Testosterone Undecanoate for Optimizing Performance During Military Operations

Eligibility criteria:
Inclusion Criteria:

          -  Men aged 18-35 years

          -  Ability to understand verbal or written instructions/testing materials in English

          -  Physically active (as determined by accelerometry and review of a physical activity
             log)

          -  Not taking any prescription medications and/or willing to refrain from all medication
             use prior to and throughout the entire study period, unless provided/approved by the
             study physician

          -  Willing to refrain from alcohol, smoking, e-cigarettes or use of any nicotine product,
             caffeine, and dietary supplement use throughout the entire study period

          -  Willing to live on the Pennington Biomedical Research Center inpatient unit for 20
             consecutive days

          -  Meets age-specific US Army body composition standards according to Army Regulation
             600-9, which includes estimates of percent body fat based on height, weight, and
             circumference measures (neck and waist)

          -  Total testosterone concentration is within the normal physiological range (300-1,000
             ng/dL)

        Exclusion Criteria:

          -  Musculoskeletal injuries that compromise exercise capability

          -  Diagnosed cardiometabolic disorders (i.e., hypertension, hyperlipidemia, kidney
             disease, diabetes, etc.)

          -  Allergies or intolerance to foods, vegetarian practices, or history of complications
             with lidocaine

          -  Anabolic steroid, human growth hormone, or nutritional testosterone precursor-like
             supplement use within the past 6 months

          -  Will not refrain from smoking (any nicotine product), alcohol, caffeine, or any other
             dietary supplement during the study

          -  Adults unable to consent

          -  Women

          -  Prisoners

          -  Sedentary or engages in insufficient quantities of physical activity per week (aerobic
             and/or resistance training as determined by accelerometry and review of a physical
             activity log)

          -  Exceeds age-specific US Army body composition standards according to Army Regulation
             600-9

          -  Previous history of kidney stones unless otherwise approved by the medical
             investigator

          -  Systolic blood pressure > 150 or diastolic blood pressure > 95 mmHg

          -  Previous history of breast or prostate cancer

          -  Previous history of Chronic Obstructive Pulmonary Disease or Obstructive Sleep Apnea

          -  Prostate-Specific Antigen (PSA) > 3ng/ml, Hematocrit > 50%, or positive urine drug
             screening

          -  Based on the investigative team's clinical judgment, a subject may not be appropriate
             for participation in the study
Male
Accepts Healthy Volunteers
Subject must be at least 18 Years old.
Subject must be at most 35 Years

Eligibility (NLI label): Entailment