GYNO: Nolvadex does not block any of the gear receptor sites, so it does not make any gear less effective. A lot of people believe it does simply because when they use a high androgenic compound (ie. testosterone), they lose a few pounds of weight and some strength (a bloated muscle/joint is stronger). This is simply because Nolvadex blocks the estrogen receptor sites, so you don't hold as much water (estrogen causes water retention). However, the gear that you are taking is still working the same at building muscle. one may use novla at 20mg a day throughout not only to stop gyno but to also stop water retention and therefore keep looking hard. it's a top dieting drug to for the above reason, and there are alot of female pros out there who cant get cuts in the lower body unless they take novladex. Use it also when u finish the cycle to retard the esyrogen backlash and to help stop fat accumulating. When people say they gain less while using novladex its only coz their not holding as much water. From the standpoint of the bodybuilder using anabolic/androgenic steroids (AAS), if nothing is done about the situation, high estrogen levels can cause gynecomastia, will inhibit natural testosterone production, and will cause bloating. High estrogen levels also make it more difficult to lose fat, and tend to cause female pattern fat distribution even in males. Though most bodybuilders feel they know which steroids aromatize and which do not, sometimes the beliefs are in error. This is because progestogenic activity (activity like that of progesterone, another female hormone) is easily mistaken for estrogenic activity. Both hormones can cause bloating, and both can cause gyno. So AAS which are capable of activating not only the androgen receptor but also the progesterone receptor are often mistakenly assumed to aromatize. (Note: these androgens do not "convert to progesterone" but rather are themselves, without any change needed, able to act on that receptor.) Nandrolone is proven to be a progestin. This fact is of clear importance in bodybuilding, because while moderate Deca-only use actually lowers estrogen levels as a consequence of reducing natural testosterone levels and thus allowing the aromatase enzyme less substrate to work with, Deca nonetheless can cause gyno in some individuals. Furthermore, just as progesterone will to a point increase sex drive in women, and then often decrease it as levels get too high, high levels of progestogenic steroids can kill sex drive in male bodybuilders, though there is a great deal of individual variability as to what is too much. Incidentally, this progestogenic activity also inhibits LH production, and contrary to common belief, even small amounts of Deca are quite inhibitory, approximately as much so as the same amount of testosterone. Methenolone (Primobolan), stanozolol (Winstrol), dromostanolone (Masteron), oxandrolone (Anavar), mesterolone (Proviron), stenbolone (Anatrofin), trenbolone, and DHT do not aromatize, and thus, antiestrogens are not relevant to these AAS either. The steroids where aromatization is of particular concern are testosterone, methandrostenolone (Dianabol), boldenone (Equipoise), and to some extent fluoxymesterone (Halotestin). However the latter is usually used in doses low enough that aromatization is not an issue. Aromatase inhibitors The most commonly used aromatase inhibitor in bodybuilding is aminoglutethimide (Cytadren). This drug also inhibits an enzyme (desmolase) necessary for synthesis of cortisol, but fortunately, aromatase can be inhibited with levels of drug that cause only limited inhibition of desmolase. Anastrozole (Arimidex) is a superior aromatase inhibitor. It is, however, very expensive. With moderate doses of testosterone it seems that 1 mg/day is sufficient, and some have claimed half a tab to be sufficient. Receptor blockers Clomiphene (Clomid) and tamoxifen (Nolvadex) are the most popular drugs of this class. They are more precisely referred to as "selective estrogen receptor modulators." This is because their mode of action is not so simple as merely blocking the estrogen receptor. Estrogen receptors require not only hormone but also activation of regions of the receptor called AF-1 and AF-2. AF-1, to be activated, requires phosphorylation, while AF-2 can be activated by any of a number of cofactors, such as IGF-1. As it happens, clomiphene and tamoxifen are estrogen receptor antagonists (blockers) in cells that depend on activation of the AF-2 region, while in cells which activate AF-1, these compounds are estrogens. In some cells these drugs activate one of the types of estrogen receptor (ERa ) but are antagonists of the other type (ERb ). The result is that these compounds are antiestrogenic in breast tissue, fat tissue, and in the hypothalamus, which is what we want in bodybuilding, but are estrogenic in bone tissue and with respect to favorable effect on blood lipid profile, both of which are, again, desirable. They also appear to have some estrogenic effect on mood, though this may be in only parts of the brain (the matter is not studied.) Cyclofenil is a similar drug to the above two. Clomiphene will do everything that the other two will do, but for some unknown reason, has been found more effective than tamoxifen both medically and in bodybuilding for increasing LH production. Raloxifene (Evista) is a new selective estrogen receptor modulator that, for women, has the advantage of being an antiestrogen in the uterus, whereas clomiphene and tamoxifen are estrogens in that tissue. For this reason, the latter two drugs can promote uterine cancer, while raloxifene actually should help prevent it, and is therefore a superior drug for women. It is not known how effective it may be in increasing LH production. A small percentage of individuals suffer vision problems from use of clomiphene, which is generally reversible upon discontinuance. These persons, of course, should not use the drug after discovering the problem. Steroids which aromatize (testosterone and Dianabol, for example) produce estrogen and lead to estrogenic side effects which non-aromatizing steroids (Winstrol and Primo, for example) do not. These effects include estrogenic bloating and estrogenic gyno. Steroids which have progestogenic activity (Deca and Nilevar, for example, and, I expect, Anadrol) cause progestogenic side effects which other steroids do not. These include progestogenic bloating, progestogenic bloating, and can include loss of sex drive, though moderate levels of progestogenic activity can increase sex drive. Winstrol seems to reduce these progestogenic side effects substantially, if used at 50 mg/day. in relation to the above: When one begins administering T at 250-500mg per week, endogenous T production begins to shut down and there is very little noticeable muscle mass gains (most weight gain is water at this point). However, as T dosages reach 1000mg per week, muscle gains are maximized. As one increases the dose over 1000mg T per week, more aromatization (conversion to estrogen) occurs and quantitatively less T is available for muscle building. Likewise, if one adds an anti-aromatase such as Arimidex to the mix, less estrogen is produced but more dihydrotestosterone (DHT) is produced. DHT production (which can result in acne, hair loss, and prostate enlargement) has very little direct anabolic properties, therefore, we are back to the same empirical conclusion-- 1000mg T per week maximizes muscle gains while minimizing estrogen and DHT production-- the two hormones responsible for testosterone-induced side effects. please criticize the above info if you feel any of it in error. otherwise i hope it is useful to you all. sorry it is so long but i felt all those concerned about these issues would want to read it. the question i have is how do you guys suggest preventing gyno while on deca? besides a small dosage of winny cus i am prone to hairloss. what a viscious circle!