Natesto Testosterone Nasal Gel for Hypogonadal Men

Inclusion Criteria: * Ability to understand and provide written informed consent for the study. * Ability to read and complete electronic questionnaires in English. * Adult males between the ages of 18-64 years * Mild-moderate ED based on SHIM score between 8-21 at study entry * Ability to take daily Tadalafil * Ability to undergo venipuncture * Ability to provide ejaculated semen sample * Stable female sexual partner with sexual activity at least 1-3 times/month * Hypogonadism defined as two (one done as SOC within the last 6 months and one done at the time of screening) early morning total testosterone lab values \<300 Exclusion Criteria: * Morbid Obesity - BMI \>35 * History of Diabetes (HBA1c \>6.0) * Hematocrit \< 35% or \> 54% at study entry * Concurrent or Prior use of other exogenous testosterone or hormone therapy (SERM, aromatase inhibitor, gonadotropins) within the last 3 months. * Concurrent use of other prescription medications for ED including PDE5 inhibitors, intracavernosal injection therapy, urethral suppositories * Concurrent use of nitrates in any form * History of pelvic radiation * Spinal cord injury * Any progressive neurologic disease (Alzheimer's, Parkinson's, multiple sclerosis, etc). * History of penile prosthesis * History of prostatectomy * History of transurethral resection of prostate * History of stroke or myocardial infarction within the past 6 months * History of congestive heart failure * History of untreated obstructive sleep apnea * History of liver disease (Serum transaminases \> 2.5 times upper limit of normal) * History of chronic kidney disease (GFR\<60 or Serum Cr \>2) * History of, current or suspected, prostate (abnormal DRE or elevated PSA \>4.0) or breast cancer. * History of azoospermia or oligospermia (\<15 million/ml) * History of vasectomy * History of Priapism * History of Polycythemia Vera * Receipt of any investigational product within 4 weeks of study enrollment * Recurrent upper respiratory or sinus infection (\>3 times/month for \>6 months) * Recurrent epistaxis (\>3 times/month for \>6 months)