Steroid Selection
When first considering what steroid(s) to use, one will notice there are many different medications that fall under the category of anabolic/androgenic steroids. This has been the result of many years of development, where specific patients and needs are addressed with drugs that have specific characteristics.
For example, some drugs are considered milder (less androgenic), and produce fewer side effects in women and children. Others are more androgenic, which makes them better at supporting sexual functioning in men. Some are injectable medications, and others made for oral administration. There are limits to this diversity, however.
All AAS drugs activate the same cellular receptor, and as such share similar protein anabolizing properties. In other words, while different AAS drugs may have some differing properties, if your objective is to gain muscle mass and strength, this could be accomplished with virtually any one of the commercially available agents.
While all AAS drugs may be capable of improving muscle mass, strength, and performance, it would not be correct to say there are no advantages to choosing one agent over another for a particular purpose.
Most fundamentally, the quantity and quality of muscle gained may be different from one agent to another.
In a general sense, AAS that are also estrogenic tend to be more effective at promoting increases in total muscle size. These steroids also tend to produce visible water (and sometimes fat) retention, however, and are generally favored when raw size is more important than muscle definition.
Drugs with low or no significant estrogenicity tend to produce less dramatic size gains in comparison, but the quality is higher, with greater visible muscularity and definition.
In reviewing the most popular AAS drugs, we can separate them into these two main categories as follows.

Mass (Bulking):
Methandrostenolone – Oral
Oxymetholone – Oral
Testosterone (cypionate, enanthate) – Injectable

Lean Mass:
Boldenone undecylenate – Injectable
Methenolone enanthate – Injectable
Nandrolone decanoate – Injectable
Oxandrolone – Oral
Stanozolol – Oral

The early stages of AAS use usually involve cycles with a single anabolic/androgenic steroid.
Building muscle mass is the most common goal, and usually entails the use of one of the more androgenic substances such as testosterone, methandrostenolone, or oxymetholone.
Those looking for lean mass often find favor in such anabolic staples as nandrolone decanoate, oxandrolone, or stanozolol.
First time users rarely welcome injecting anabolic/androgenic steroids, and will usually choose an oral compound for the sake of convenience.
Methandrostenolone is the most common choice for mass building, and is almost universally regarded as highly effective and only moderately problematic (in terms of estrogenic or androgenic side effects).
Stanozolol is the oral anabolic steroid most often preferred for improving lean mass or athletic performance.
The potential for adverse reactions should also be considered when choosing a steroid to use, especially if AAS use is to be regularly repeated. For example, the listed oral medications present greater strain on the cardiovascular system, and are also liver toxic. For these reasons, the injectable medications listed are actually preferred for safety (testosterone most of all).
Potential cosmetic side effects may also be taken into account. For example, men with a strong sensitivity to gynecomastia sometimes prefer non-estrogenic drugs such as methenolone, stanozolol, or oxandrolone.
Individuals worried about hair loss, on the other hand, may isolate their use to predominantly anabolic drugs, such as nandrolone, methenolone, and oxandrolone.
A detailed review of personal goals, health status, and potential side effects of each drug is advised before committing to any AAS regimen.

Use Responsibly,