Anabolic Steroid Classification System – Class I and Class II Androgens

Classification corresponding to synergistic effect: pharmaceutical androgens

A method that has proven useful in predicting stacking behavior of androgens other than testosterone is to systematically group them as either “Class I” or “Class II.” Pairs of androgens which combine with little or no synergy are assigned to the same class. Androgens combining very synergistically are assigned to different classes.

The first assignment is arbitrary. Let us say that trenbolone is assigned to Class I. Then methenolone, nandrolone (Deca), boldenone (Equipoise), and oxandrolone are also assigned to this class, since none of them act synergistically with trenbolone: a greater effect cannot be achieved by adding them than can be achieved with trenbolone alone at a sufficient dose.

As it happens, no combination of these Class I compounds proves much if at all synergistic, either, so the classification method is a logically consistent one.

Dianabol, on the other hand, combines very synergistically well with TA or other Class I compounds. It therefore is categorized as Class II. Other Class II pharmaceutical steroids include Anadrol® and Winstrol.

It’s interesting to note that while both are Class II steroids, some synergy is observed between Winstrol and Dianabol. It is not, however, nearly as strong as the synergy between either of them and any Class I compound. While differing in some common way from all Class I compounds, in some cases Class II compounds may have some differences among themselves: Winstrol may have an activity that Dianabol for example does not, or possesses to a lesser extent.

It may be noted that where binding to the androgen receptor is known, those compounds that have good binding to the androgen receptor are invariably Class I, and those that do not (while having good anabolic effect regardless) are invariably Class II.

If one prefers, Class I steroids may be defined as those binding well to the androgen receptor, while Class II steroids are those which do not, yet have good anabolic effect.

Some discussion of the fact that androgens have more than one mechanism of action can be found in a previous article, Pharmacological Differences Among Anabolic/Androgenic Steroids. It is to be expected that where mechanisms of action may differ between drug compounds, combinations will yield synergy.

About the author

Bill Roberts

Medicinal chemist

Bill Roberts is an internationally-recognized expert on anabolic steroids and performance-enhancing drugs (PEDs). He received a bachelor degree in Microbiology and Cell Science and completed the educational and research requirements for a PhD in Medicinal Chemistry at a major American university.

Bill entered the nutritional supplement industry prior to completing his doctoral thesis but his education was invaluable so far as being able to design/improve nutritional supplement compounds, since it was in the field of designing drug molecules and secondarily some work in transdermal delivery.

His education was not specifically "geared" toward anabolic steroids other than expertise with pharmacological principles having broad applications. This has allowed Bill to provide unique insight into the field of anabolic pharmacology with knowledge of points which he would not have known otherwise.