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Esterification & Anabolic Steroids

by Mike Arnold

In this article we will take a look at the process of esterification and how ester length affects both our appearance, as well as the activity of the AAS to which they are attached. Most steroid users have a basic understanding of esters and their effect on release rate, but a much smaller percentage of individuals are informed regarding the full significance of ester length. By gaining a more thorough understanding of how esters affect the body, we will be able to employ them in a manner more conducive to achieving our goals.

Esters were originally developed for the sole purpose of extending the life of a steroid within the body. An ester is a molecular chain comprised primarily of carbon and hydrogen atoms, which is then attached to the parent steroid at the 17th carbon position. The longer an ester is (the more atoms which are included in the chain), the more time it will take for the attached steroid to be released into the bloodstream and be fully utilized by the body. The fundamental advantage of longer esters is that they enable the individual to adhere to a less frequent injection schedule, while still maintaining fairly even blood levels of the drug. Shorter esters will necessitate a more frequent injection schedule, in order to minimize blood level fluctuations of the attached hormone.

In the following text you will see two columns, with each one containing a list of steroid esters. The 1st column groups the various esters according to their length, while the 2nd column groups them according to their half-lives. See below.

Number of carbon atoms per ester

Formate: 1
Acetate: 2
Propionate: 3
Butyrate: 4
Valerate: 5
Hexanoate: 6
Heptanoate: 7
Enanthate: 7
Octanoate: 8
Cypionate: 8
Nonanoate: 9
Decanoate: 11

Ester half-life

Formate: 1.5 days
Acetate: 2 days
Propionate: 3 days
Phenylpropionate: 4.5 days
Butyrate: 6 days
Valerate: 7.5 days
Hexanoate: 9 days
Caproate: 9 days
Isocaproate: 9 days
Heptanoate: 10.5 days
Enanthate: 10.5 days
Octanoate: 12 days
Cypionate: 12 days
Nonanoate: 13.5 days
Decanoate: 15 days
Undecanoate: 16.5 days

While being able to inject less frequently is an appealing benefit of longer esters, injection frequency is only one of several factors which should be considered prior to deciding which ester is most appropriate for the user. In order to illustrate this point, let us use testosterone as an example. How many times have you read the statement “test is test”? If you’ve been active on the boards for any length of time, chances are likely you have seen this comment repeated quite a few times, but does that make it true? From a results point of view, the answer is conclusive no.

In reality and despite testimony to the contrary, ester length determines much more than just release rate. This fact has been well known among BB’rs for decades, although an explanation for how this occurs has been sorely lacking. One explanation which has been put forward in recent years states that ester length influences the rate of both aromatization and 5-a reduction. When looking at all the evidence on the table, this argument certainly seems plausible, especially in regards to estrogen conversion. At the very least and in light of the fact that no other logical explanations have yet been presented, it deserves some attention.

In evaluating the evidence in favor of the above argument, the most notable difference between the various esters is their ability to influence water retention to varying degrees. Ask anyone who has run both test cypionate, as well as test propionate and see what they say. Test cypionate is well known in the AAS community to cause significant sub-q water retention, while test prop is not. This is why test prop is so heavily favored among pre-contest BB’rs and why test cyp is avoided like the plague during the later stages of contest preparation. We see the same thing happening with the nandrolone esters. Nandrolone decanoate (Deca) use is typically characterized by heavy amounts of water retention, while its shorter-estered cousin, NPP (nandrolone phenyl propionate), is far less prone to cause this side effect. Across the board, this pattern is impossible to deny when I comes to esterfied aromatizable steroids.

Now, one might argue that estrogen conversion has nothing to do with the increased water retention witnessed with longer estered aromatizing drugs and that another mechanism is responsible for this effect. However, if this were true, shouldn’t we expect to see non-aromatizing drugs behaving in a similar fashion? That would be a reasonable assumption, but this is not the case. In reality, non-aromatizing drugs, such as Trenbolone or Masteron, are not affected by ester length when it comes to water retention. If ester length has no bearing on estrogen conversion and another mechanism was responsible, then why don’t longer-estered non-aromatizing drugs lead to increased water retention like their aromatizing counterparts?

Adding additional credibility to this argument is the fact that longer testosterone esters are also more likely to cause female breast tissue development (commonly referred to as gynecomastia) than shorter esters. Some may disagree with this claim, but real-world evidence has repeatedly confirmed that when using equivalent doses, short esters are less likely to cause this side effect than longer esters.

Citing the above examples are not definitive proof that ester length directly influences estrogen conversion, but given the circumstances, and with no alternative explanations available, it certainly points in that direction.

Based on the information presented so far, shorter esters appear to offer significant benefit over longer esters, aside from the increased injection frequency. After all, they result in less water retention, lead to an improved appearance (a drier look), and are less likely to cause gynecomastia. With long esters being devoid of these benefits, many users would not find the advantage of a less frequent injection schedule to be sufficient in justifying the use of longer estered AAS. Fortunately, the benefits of longer esters do not end with a reduced injection frequency, but extend into the area of potency. A noteworthy advantage of longer esters is that they provide a greater increase in total protein synthesis, per mg, compared to shorter esters. That’s correct, long esters pack a greater anabolic punch.

Some individuals wrongly assume that shorter esters are more potent, due to the fact that they contain a greater percentage of testosterone, per mg. While it is true that shorter esters do contain more testosterone per mg, this is not necessarily indicative of a steroid’s anabolic potency. When an ester is attached to a steroid, the ester itself makes up a potion of the total weight of the steroid. For example, testosterone cypionate contains 69.9% testosterone per mg, while the attached cypionate ester makes up for the remaining 31% of the total weight of the steroid. In contrast, test prop contains 83.7 mg of testosterone, per mg. In addition, because shorter esters release the parent steroid into the bloodstream at a more rapid rate, gains are often times realized more quickly. Under these circumstances, it is easy to see how someone might assume that shorter esters are more potent on mg to mg basis. However, research dating back to the 50’s demonstrates otherwise, with longer esters consistently being shown to exhibit a greater net anabolic effect.

Below is a list of the more commonly used esters, which have been grouped together according to the percentage of testosterone they contain per mg.

Percentage of Testosterone per mg

No Ester: 100mg
Acetate: 87.26mg
Propionate: 83.72mg
Enanthate: 71.99mg
Cypionate: 69.90mg
Decanoate: 65.15mg

Lastly, short esters offer a couple minor benefits not found with longer esters. For one, should a particular side effect manifest which is deemed unacceptable to the user, it generally takes no more than a few days for that side effect to dissipate after discontinuing a short estered steroid. However, one may have to wait weeks to find relief after discontinuing a longer ester. This is less likely to be an issue in experienced users, but beginners or intermediates who are using a new steroid for the first time may want to consider the use of a shorter ester until they know how they respond. One example where the use of a shorter ester would be ideal is when administering trenbolone for the first time. With trenbolone being notorious for causing bothersome side effects in a significant percentage of users, wisdom would call for the use of tren ace over tren enth on one’s 1st run. Once the individual is aware of their personal response to a specific drug, this factor begins to lose relevancy.
When it comes to the post-cycle period, ester length will determine how long one must wait after their final inject before they can begin PCT. Since a Serm-based PCT is ineffective in the presence of active AAS, post cycle therapy can commence only after all ASS have cleared the system.

As you can see, ester length effects much more than just injection frequency/release rate; it also has a direct effect on water retention, net protein synthesis, gynecomastia risk, and a likely influence on estrogen conversion (and possibly 5-a reduction, as well). I think we can safely dispel the myth that “test is test”. So, the next time you’re trying to decide what ester to include in your cycle, let your selection be guided by the above factors as they relate to your goals, not on injection frequency alone.

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