Steroid isolation , depending on context, is the isolation of chemical matter required for chemical structure elucidation, derivitzation or degradation chemistry, biological testing, and other research needs (generally milligrams to grams, but often more  or the isolation of "analytical quantities" of the substance of interest (where the focus is on identifying and quantifying the substance (for example, in biological tissue or fluid). The amount isolated depends on the analytical method, but is generally less than one microgram.  [ page needed ] The methods of isolation to achieve the two scales of product are distinct, but include extraction , precipitation, adsorption , chromatography , and crystallization . In both cases, the isolated substance is purified to chemical homogeneity; combined separation and analytical methods, such as LC-MS , are chosen to be "orthogonal"—achieving their separations based on distinct modes of interaction between substance and isolating matrix—to detect a single species in the pure sample. Structure determination refers to the methods to determine the chemical structure of an isolated pure steroid, using an evolving array of chemical and physical methods which have included NMR and small-molecule crystallography .  : 10–19 Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity. 
Finally, the life of a steroid-user is not as glamorous as it seems. Steroids are expensive and illegal. They can do jail time if caught, and there are a lot of ancillary drugs and supplements that must also be taken to minimize the damage to their organs or to keep certain hormones in normal ranges (ex: Nolvadex). Their bloodwork (hematocrit, cholesterol profile, etc.) and blood pressure is often atrocious. They battle with sleep apnea and fluctuating moods and sex-drives, and many have trouble performing simple daily task such as wiping their butts or washing their backs. Last, their caloric intake is much higher (and expensive), and it becomes a chore to meet calorie and protein requirements day in and day out. The grass is not always greener on the other side.
Progestins , the most important of which is progesterone , are the other type of female sex hormone and are named for their role in maintaining pregnancy (pro- gestation ). Estrogens and progestins are secreted cyclically during menstruation . During the menstrual cycle , the ruptured ovarian follicle (the corpus luteum ) of the ovary produces progesterone, which renders the uterine lining receptive to the implantation of a fertilized ovum . Should this occur, the placenta becomes the main source of progesterone, without which the pregnancy would terminate. As pregnancy progresses, placental production of progesterone increases, and these high doses suppress ovulation , preventing a second conception . The contraceptive quality of progesterone led to the development of structurally modified progestins and estrogens—the oral contraceptives known as birth-control pills, used by women to prevent unwanted pregnancy.