Drugs such as Nolvedex bind to the oestrogen receptors , therefore reducing the effects of the heightened oestrogen in the body. Such drugs do nothing to reduce the amount of oestrogen in the body; they merely reduce its effects via competition for the receptors . If the user wishes to reduce the amount of oestrogen they should look to drugs such as proviron and anastrozole , which are known as anti-aromatases - . they lower the conversion of the steroid to oestrogen and therefore reduces the overall amount of oestrogen present.
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. 
steroid ster·oid (stěr'oid', stēr'-)
Any of numerous naturally occurring or synthetic fat-soluble organic compounds having as a basis 17 carbon atoms arranged in four rings and including the sterols and bile acids, adrenocortical and sex hormones, certain natural drugs such as digitalis compounds, and the precursors of certain vitamins. Also called steroid hormone . adj. ste·roid·al (stĭ-roid', stě-)
Relating to or characteristic of steroids or steroid hormones.