The Anabolic Index

The Anabolic Index is a measure of the ratio of anabolic to androgenic effect of a particular steroid compound. An Anabolic Index greater than one shows a higher tendency for an anabolic effect, thus classifying an anabolic steroid, whereas a measure of lower than one, assess the steroid as an androgen.


A pure anabolic compound was never, and has never been invented. Chemists have been able to create a number of compounds and preparations that are in fact much milder than testosterone itself. For example, the well known Nandrolone (19-Nortestosterone) compound actually converts to estrogen at a much lower rate than testosterone, while also metabolises into less potent DHT (Dihydrotestosterone) structure, in this case Dihydronandrolone. Unlike testosterone, and quite unusually, the activity of nandrolone is actually reduced in tissues such as the prostate that are high in 5a-reductase enzyme, thus creating a very favourable anabolic to androgenic ratio. Other such steroid preparations such as Winstrol, also produce no estrogen in the body. With moderate use drugs such as Winstrol, Primobolan and Anavar lead to far fewer and less uncomfortable side effects.


When we discuss compounds that are classed as more anabolic than some of their androgenic cousins - what does this actually mean? Well, simply, it means that the particular drug in question exhibits far more muscle growth results, rather than androgenic side effects - such as hair growth and deeper voice etc. Both effects are mediated at all times via the same receptor site in the body - the androgen receptor, we will usually find that the reduction of the androgenic activity of a steroid will have a knock on effect of lowering the muscle building effectiveness. When we purely look into muscle growth, the androgenic based steroids have a much greater affinity to bind to the androgen receptor site, and thus are typically far more effective at building muscle mass than the true anabolic steroids, since these have a poor affinity to the receptor. One would probably have assumed it to be the other way round, since the anabolic steroid should logically build more muscle, although it just doesn't work that way in the real world, due to the affinity to the androgen receptor site. Never forget that throughout the years of scientific research into the thousands of chemical analogues of testosterone produced, the king muscle building agent of all time, has proven to be the base androgen itself - testosterone. Unfortunately the steroid user will always suffer far more side effects when using the androgen based drugs. Therefore there may always be a trade off in the question of planning a successful cycle. Does one go for the milder and less androgenic drugs, to experience a safer, more comfortable cycle while simply gaining less overall mass, or do you take a higher androgenic drug and put up with the side effects?


It is also not true to state the all of the androgenic drugs are prime muscle building agents. This is not true. There are actually some exceptions. The clearest example is that of Dihydrotestosterone, or DHT. Your body will convert testosterone into DHT as a way to potentate its action in certain tissues such as the scalp, skin, prostate etc. Your body will also lower its activity in certain target tissues such as muscles, to lessen the effects. The body accomplishes this simply by rapidly reducing the DHT into far less effective metabolites such as androstanediol, accomplished by the presence and interaction in muscle tissue and other tissues, of the 3-alpha hydroxysteroid dehydrogenase enzyme. So you will find that DHT is greatly open to affect and alteration by this particular enzyme than testosterone, even though it has a far greater affinity for the androgen receptor than its parent, DHT is rendered into exhibiting far less anabolic activity.


A more modern approach to assessing the actual muscle building affects of steroid drugs is the measure of comparing the relative binding affinity (RBA) of the steroid compound to the androgen receptor (AR). Aside from the above discussed DHT and Mesterolone (Proviron), we can see a clear trend of uniformity that with the remaining anabolic/androgenic steroids seem to bind to the receptors in both tissues with near equal affinity.