Pharmaceutical Name: Testosterone (as Enanthate)
Chemical structure: 4-androstene-3-one,17beta-ol

Characteristics:
Testosterone is the prime male androgen in the body, and as such still the best possible mass builder in the world. It has a high risk of side-effects because it readily converts to a more androgenic form (DHT) in androgen responsive tissues and forms estrogen quite easily. But these characteristics also provide it with its extreme anabolic tendencies. On the one hand estrogen increases growth hormone output, glucose utilization, improves immunity and upgrades the androgen receptor, while on the other hand a testosterone/DHT combination is extremely potent at activating the androgen receptor and eliciting major strength and size gains. While not always the most visually appealing result, there is no steroid on earth that packs on mass like testosterone does.

Although Testosterone enanthate is effective for several weeks, it is injected at least once a week since Testosterone enanthate has a plasma half-life time in the blood of only one week.
Like testosterone cypionate, enanthate is a single-ester and long-acting form of the base steroid testosterone. To me, its slightly better value for money than the aforementioned because its ester is only 7 instead of 8 carbons in length. Where that doesn't really change much in terms of release and blood concentration for users who inject on a weekly basis, that does mean that less of the weight is ester and more of it is testosterone. When taking an amount of an esterified steroid, that amount in terms of weight is a combination of the ester and the steroid. Naturally the longer the ester is, the more of the weight it takes up. So its safe to state that 500 mg of enanthate contains more testosterone than does 500 mg of cypionate. Not that this slight difference will be noted on a weekly pattern really, but its enough for me to give it a slight edge if given the choice. Although, as stated with cypionate, your choice between enanthate and cypionate is best based on availability. These are a much better choice than sustanon 250 or omnadren, which are blends of different testosterone esters, due to their irregular release. Nonetheless these versions still appear to be more popular with most users for some reason. Before you compare these to shorter esters under the pretense that even more of the weight would be testosterone, for bulking purposes the release pattern and injection pattern of an enanthate or cypionate is more fitting than that of say, a propionate ester. Enanthate and cypionate are very close in those terms, hence the comparison is possible.