Kim ED, McCullough A, Kaminetsky J Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement. BJU Int. 2016 Apr;117(4):677-85. doi: 10.1111/bju.13337. Epub 2015 Oct 23.
Rhoden EL, Morgentaler A Risks of testosterone-replacement therapy and recommendations for monitoring. N Engl J Med. 2004 Jan 29;350(5):482-92. Review.
Rogol AD, Tkachenko N, Bryson N Natesto™ , a novel testosterone nasal gel, normalizes androgen levels in hypogonadal men. Andrology. 2016 Jan;4(1):46-54. doi: 10.1111/andr.12137. Epub 2015 Dec 22. Erratum in: Andrology. 2017 Jul;5(4):844.
Ullah MI, Riche DM, Koch CA Transdermal testosterone replacement therapy in men. Drug Des Devel Ther. 2014 Jan 9;8:101-12. doi: 10.2147/DDDT.S43475. eCollection 2014. Review.
Natesto Effects on Testosterone, Luteinizing Hormone, Follicle Stimulating Hormone and Semen Parameters
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.