1954, a researcher named Reifstein and his colleagues compared an injection of Testosterone Propionate with Testosterone Enanthate, and they found that the injection of testosterone propionate resulted in nitrogen retention of 1.02g/day with a total measurable anabolic activity of 12 days, while the Enanthate version resulted in nitrogen retention of 1.76g/day and had a total measurable anabolic activity of 33 days. (1). Therefore, a 200mg shot of Testosterone (long ester) is going to have a greater overall anabolic effect than a 200mg shot of a short ester.
So does that mean that the ester effects the anabolic ability of the actual steroid. Well, yes, that would seem to be the case. If a steroid hangs out in your body for a longer amount of time, and helps you retain more nitrogen, then its overall anabolic effect would be greater. Granted, they’re studying a single injection- but with a typical injection schedule of testosterone propionate, as compared to testosterone enanthate, most people gain more weight from the enanthate version. Think about it; experience tells us that with an every other day injection schedule of 100mgs of testosterone propionate versus 400mgs/week of testosterone enanthate, most people gain more weight from the enanthate. Yet, the actual amount of injected (pure) testosterone is virtually the same, even when you subtract the weight of the ester.
Also, testosterone’s effect on Growth Hormone and IGF-I (two very anabolic hormones) are also dependent on aromatization to estrogen? Again, this is why we gain more muscle with the long estered tests. This means that you actually get far more anabolism from the longer estered testosterones, because the increased conversion to estrogen will provide a greater elevation in your GH and IGF-1 levels. And many other positive effects of testosterone are actually dependent on it’s conversion to estrogen as well. Yes, long ester chained TEST create more estrogen than short esters, however, they are more anabolic than short esters, that's why you always hear people bulk on long esters and cut on short esters..
Therefore, long esters are more anabolic than short esters, which they are more beneficial when wanting to slab on muscle.