Buster's research and clinical practice in reproductive medicine include published studies in steroid physiology, pre-implantation embryology, pregnancy loss, and menopausal hormone replacement therapy. Buster authored "Sex and the 50-Something Woman: Strategies for Restoring Satisfaction" in the journal
Contemporary Obstetrics and Gynecology. The intent was to explain the various causes of
female sexual dysfunction (FSD) and the simple interventions obstetrician/gynecologists and primary care physicians can recommend. The article attracted national interest with stories appearing in local media. One of Buster's earliest research studies focused on
steroid hormone radioimmunoassay (RIA). He reported an RIA for the androgen prohormone,
dehydroepiandrosterone sulfate (DHEA-S), the direct measurement of which was shown to be possible in un-extracted serum. Refined versions of his methodology are used in the diagnosis and management of androgen excess disorders in women. He also described for the first time the simultaneous progression of multiple androgen, progestin, and estrogen concentrations in maternal blood throughout all three trimesters of pregnancy and into the onset of labor. Buster helped develop a
testosterone delivery system for women researched by
Procter & Gamble. It is marketed in Europe under the brand name
Intrinsa. Buster served as lead investigator in another study demonstrating the effectiveness of an estradiol mist, which has pharmacology similar to those of a trans-dermal estrogen patches. Sold in the United States by
Perrigo under the name Evamist, it received FDA approval in 2007. Buster's Phase III Study for Evamist was published in the journal,
Obstetrics & Gynecology. In the early 1980s, over a period of 4 years, at the
University of California at Los Angeles School of Medicine, In February 1984, the first live birth, followed 3 months later by a second live birth, resulted from these techniques and was reported by Buster and his team. Buster updated the uterine lavage technology adapting it to diagnosis and prevention of genetic diseases in embryos. In 2011 Buster founded Previvo Genetics, Inc. He serves on the Board of Directors and Scientific Board. In April 2019 at the International Federation of Fertility Societies (IFFS)World Congress in Shanghai, China, Buster presented the preliminary results from the first Preimplantation Genetic Testing (PGT) using
in vivo Embryos recovered by Uterine Lavage. In January, 2020, Buster with the Previvo research team reported the first large series (134 hyper stimulation/lavage cycles) describing the successful and safe recovery of 136 in vivo fertilized and matured embryos using in vivo uterine lavage (IVL). For controls, 20 of the lavage subjects also underwent in vitro fertilization (IVF). Most significantly the morphology scores of the IVL blastocysts were significantly higher than the IVF controls. File:John Buster IFFS2019.jpg ==Awards and honors==