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. 
While the human body manufactures an endogenous Testosterone level in the range of 70mg/week, the Testosterone dosage required for physique and performance enhancement must sit well above that, with a minimum being in the range of 300 – 500mg per week for beginners, for example. Intermediate and/or experienced anabolic steroid users can venture even higher than that. In addition to the higher bodybuilding dosage, the injections must be administered much more frequently. While TRT patients can ‘get by’ with a single 250mg injection of Testosterone Enanthate once per week (or even once every two weeks as is commonly applied clinically), an athlete or bodybuilder would have to administer 250mg of Testosterone Enanthate twice per week (for a total of 500mg) in order to experience a steady onset of performance and physique enhancing benefits. This is very necessary due to a constant steady peak blood plasma level of the anabolic steroid that is necessary for constant biological action within muscle tissue in the body. Testosterone Enanthate, as mentioned earlier in this article, exhibits a half-life of 7 – 10 days, but although its half-life is 7 – 10 days, sharp declines in blood plasma levels begin to occur several days before the end of the half-life period. When performance and physique enhancement is desired, the administration of doses must occur more frequently in order to keep blood plasma levels elevated as best as possible. For medical purposes such as TRT, sharp spikes and peaks and valleys in blood plasma levels can be afforded (although it is still not optimal), as the patient is simply utilizing Testosterone to obtain normal physiological levels, and is therefore not particularly concerned with dramatic performance or physique changes on a weekly basis.
Anabolic steroids differ in their characteristics, which means there are steroids that are only suitable for specific uses. For instance, Trenbolone is not recommended for bulking but it is an outstanding fat burner. This makes it perfect for a lean mass cycle or a cutting cycle. Always take the side effects of a particular compound into consideration whenever you plan a stack. Do not combine anabolic steroids that show similar side effects. For example, never combine Anapolon and Dianabol because they are already quite toxic and if you combine them, the toxicity will increase exponentially and cause serious damage to your body.