“Testosterone comes in various preparations, esterified variants, and forms.
Each preparation will be described and covered here.”
The Main Testosterone Esters
With the exception of a few products, almost all injectable anabolic steroids undergo a process called esterification.
Esterification is a chemical reaction where a carboxylic acid of varying lengths is chemically bonded to the anabolic steroid at the 17-beta hydroxyl group.
This is known as esterification (or an ester bond), and the ester serves to prolong the release rate and half-life of the hormone in the body.
This happens when enzymes cleave off the ester attached to the anabolic steroid.
This process primarily occurs in the liver, but it also happens in the bloodstream.
The body must first break down the ester via the aforementioned enzymes before the anabolic steroid hormone can act freely in the body.
By this time, the anabolic steroid has left the injection site and is circulating systemically throughout the body.
As a result, all anabolic steroids act systemically, based on the body’s needs, rather than acting locally or site-specifically.
For example, Testosterone Suspension is a form of unesterified testosterone, where pure testosterone is suspended as crystals in water.
Pure, unesterified testosterone has a very short half-life, making it not only too brief for practical use but also inconvenient to administer.
Therefore, to make administration easier and to extend the half-life to a more practical and usable length, various types of ester bonds have been formed, creating different esterified testosterone variants.
Adding an ester bond to the testosterone molecule allows for the maximization of its use in both medical and non-medical applications.
While an almost infinite number of esterified forms and testosterone variants can be created or discovered, there are three primary popular types well-known in both the medical community and the anabolic steroid-using community.
These are (in order of popularity):
1. Testosterone Enanthate
2. Testosterone Cypionate
3. Testosterone Propionate
In addition to these esterified variants, there are also what are known as Testosterone Blends, which are preparations and products that mix the aforementioned esterified forms of testosterone.
For example, one of the most well-known blends is Sustanon 250, which contains a total of 250mg of testosterone divided into the following mixture:
30mg of Testosterone Propionate, 60mg of Testosterone Phenylpropionate, 60mg of Testosterone Isocaproate, and 100mg of Testosterone Decanoate, for a total of 250mg of testosterone esters (hence the number 250 in the name Sustanon 250).
There are also other types of blend products that contain different amounts of various testosterone ester types, such as a 450mg blend of several different testosterone esters.
There are also other less popular esterified forms of testosterone, such as Testosterone Acetate, as well as the other testosterones included in the Sustanon 250 blend (Testosterone Decanoate, Phenylpropionate, Isocaproate, etc.), but for the purposes of this article, we will focus on and discuss in detail the three main types listed above.
Testosterone Enanthate
Testosterone Enanthate is perhaps the most popular and most widely used esterified testosterone variant.
This is primarily due to its longer half-life and extended release period, which makes it more convenient for injection administration protocols.
Testosterone Enanthate has a half-life of about 7 to 10 days, allowing it to be conveniently injected once or twice a week, unlike Testosterone Propionate, which must be injected every other day.
Unesterified testosterone, like Testosterone Suspension, requires even more frequent injections—at least once a day—which is even less ideal for those who fear needles or don’t wish to inject frequently.
Thanks to its long half-life, it is better suited for medical and TRT (Testosterone Replacement Therapy) use, but as mentioned, it is also suitable for performance-enhancing purposes if one does not wish to inject frequently.
2. Testosterone Cypionate
Testosterone Cypionate, while chemically different from Testosterone Enanthate, is considered almost equivalent.
Testosterone Cypionate has a similar half-life, although it’s slightly longer (about 12 days for Testosterone Cypionate versus about 10 days for Testosterone Enanthate).
Another key difference between the two is their country of origin; Testosterone Enanthate is primarily an international product produced overseas, whereas Testosterone Cypionate is traditionally an American product.
Both products have very similar half-lives and are almost equally popular among anabolic steroid users, although Testosterone Enanthate is more popular.
In fact, the two esterified testosterone variants are so similar that they can be easily interchanged within a cycle (e.g., someone running a 10-week testosterone cycle could use Testosterone Enanthate for the first 5 weeks and switch to Testosterone Cypionate for the remaining 5 weeks without any issues).
The convenience of Testosterone Cypionate is identical to that of other long-acting compounds like Testosterone Enanthate, offering the ease and convenience of less frequent administration.
3. Testosterone Propionate
Testosterone Propionate is the third most popular of the three main testosterone ester types, but it was the very first esterified form of testosterone.
The Propionate ester extends the half-life of testosterone in the body to about 4.5 days, which is much shorter than the two previously discussed esterified testosterones.
Therefore, it requires much more frequent injection and administration protocols (at least every other day) than the other ester types to maintain stable plasma hormone levels, making it less popular among the majority of individuals who prefer less frequent injections.
Nevertheless, this doesn’t mean Testosterone Propionate is an unpopular anabolic steroid.
On the contrary, it is very popular and serves the needs of a particular niche of users who favor it.
It is only the least popular of the three due to its inconvenient and cumbersome injection and administration schedule.
Achieving Stable Plasma Levels with the Three Esterified Testosterone Variants
It is crucial to understand the importance of maintaining stable plasma levels of the hormone to ensure proper optimal gains, optimal physiological function, and a reduction in the incidence of side effects.
While many anabolic steroids are esterified to increase the hormone’s release and half-life, esterification does not guarantee completely stable peak blood concentrations.
Even long-esterified testosterone variants like Testosterone Enanthate, Testosterone Cypionate, and Testosterone Decanoate exhibit a very rapid release of the hormone from the injection site post-administration, and the enzymatic removal of the ester causes a fairly rapid rise in plasma concentrations of Testosterone relative to the total half-life of the long ester [1].
Maintaining proper and stable peak blood Testosterone levels is essential for the hormone to function correctly, so understanding this is very important when it comes to proper dosage and administration schedules.
Blood levels for almost all ester types peak approximately 48 hours after injection.
This also means that despite the misinformation that esterified testosterone variants take longer to ‘kick in’, these compounds actually begin to work very quickly after injection administration.
The difference between these esters is the time it takes to reach optimal plasma blood levels, which is generally reached over a longer period for long esters like Cypionate and Enanthate.
The ‘lifespan’ of an esterified hormone (in this case, Testosterone) is increased by the ester due to the time it takes for enzymes to liberate the hormone from the attached ester.
Part of the release rate of esterified anabolic steroids is also related to their solubility in fat, although this does not impact the half-life as much as the enzymatic cleavage of the ester itself.
Because esters are long hydrocarbon chains classified mostly as fats, they are lipophilic (fat-soluble), and therefore, the compounds they are chemically bonded to also become lipophilic (in this case, Testosterone).
Testosterone and all anabolic steroids are already in a lipid (fat) form, so adding an ester increases the hormone’s solubility in oils and fats.
After injection, the oil containing the hormone forms a reservoir (depot) within the muscle tissue, and the hormone gradually separates from the lipophilic oil to circulate into the bloodstream.
Therefore, it stands to reason that the longer the hydrocarbon chain of the ester, the more fat-soluble the hormone becomes, and thus the longer it will be released for.
This is why anabolic steroids with very long ester chains, such as Deca-Durabolin (Nandrolone Decanoate), are known to have long half-lives and remain in the body’s fatty tissues for months after administration has ceased.
Once the hormone is released from the injection site into the bloodstream circulation, enzymes act to cleave the ester from the hormone, as we have already mentioned several times.
It is very important to note that while the hormone is bonded to the ester, the anabolic steroid hormone is in an inactive state and cannot do anything until the ester is removed.
Considering the half-lives of the different types of testosterone esters, there are various protocols to consider for achieving stable plasma levels.
There are also differences between those who intend to use Testosterone for athletic and physique enhancement purposes and those who intend to use it for TRT purposes.
First, it must be explained that the use of any ester type of Testosterone for TRT allows for a much more lenient and relaxed injection protocol than for performance-enhancing purposes.
This is because the overall goal of TRT is to maintain normal physiological Testosterone levels and proper normal physiological function.
Therefore, individuals using the following Testosterone variants for TRT should operate efficiently and follow proper injection frequency protocols as outlined in medical prescription guidelines.
Testosterone Enanthate (TRT): Administered (injected) once every 2-4 weeks.
Testosterone Cypionate (TRT): Once every 2-4 weeks (injected).
Testosterone Propionate (TRT): Administered (injected) 2-3 times per week (on average, a Mon/Fri or Mon/Wed/Fri injection protocol).
Sustanon 250 or any Testosterone Blend (TRT): Once every 3 weeks (injected).
Injection protocols and frequencies for TRT purposes are not set in stone and can be adjusted at any time based on discussions and decisions between the patient and doctor.
For example, many doctors often work with their patients to set up a weekly injection schedule for Testosterone Enanthate or Cypionate.
Many medical professionals believe that the injection protocols stated in medical prescription guidelines need to be revised to allow for more frequent injections to achieve more stable blood levels, but nevertheless, the medical prescription guidelines remain as stated above.
However, the general idea here is to emphasize the fact that injection frequency can be adjusted at any time according to individual needs, especially after monitoring through blood work.
The administration protocols for the different types of testosterone esters for athletic and physique enhancement are very different and require much more frequent injection protocols and schedules.
This is because it is necessary to specifically increase changes in strength, size, and body composition while minimizing the incidence of side effects, which can only be achieved by properly reaching peak plasma concentrations.
Testosterone Enanthate (performance enhancement): Administered (injected) twice per week, with each injection spaced evenly apart (e.g., Monday and Thursday injections).
Testosterone Cypionate (performance enhancement): Administered (injected) twice per week, with each injection spaced evenly apart (e.g., Monday and Thursday injections).
Testosterone Propionate (athletic performance enhancement): Administered (injected) once every other day.
Sustanon 250 or any Testosterone Blend (athletic performance enhancement): Administered (injected) once every 7-10 days, with some protocols possibly requiring administration every 3 days.
Although ester forms of Testosterone like Cypionate or Enanthate have long half-lives of about 10-12 days, for physique and athletic enhancement, at least weekly administration is essential, with the best approach being twice-weekly administration, evenly spaced apart.
While it’s possible to get by with weekly injections, it’s not recommended because unstable blood levels lead to a higher incidence of side effects and a lower likelihood of achieving the desired effects on athletic performance.
Blended products like Sustanon 250 are a complex and interesting topic, as the disadvantages of Sustanon 250 for athletes and bodybuilders compared to other single testosterone ester types have already been defined many times.
These disadvantages are primarily due to the difficulty in controlling the varying release rates of the different testosterone esters within the Sustanon 250 mixture.
Therefore, users who intend to use Sustanon 250 (or any type of blended testosterone product) will find they have much less control and management over half-life and proper dosing.
Nevertheless, to enhance physique and athletic performance, Sustanon 250 should be administered approximately every 7-10 days instead of the medical guideline of once every 3 weeks.
Some people even prefer to administer Sustanon 250 every 3 days due to the short-ester testosterone variants used in the blend.
If the product is a blend (whether it’s Sustanon 250 or another underground lab type of custom blend), you should always base your administration protocol on one of the ester types within the blend.
The two ester types that constitute the largest amount among all other ester types within the product.
The shortest ester type (if it constitutes the highest concentration among all other ester types in the blend).
Medical References
[1] Testosterone Action Deficiency Replacement 2nd ed. E. Nieschlag HM Behre (Eds.) Springer-Verlag Berlin Heidelberg New York (1998)
[2] Aromatization of androstenedione and 19-nortestosterone in human placenta, liver and adipose tissue (abstract). Nippon Naibunpi Gakkai Zasshi 62 (1986:18-25)
[3] Long-term testosterone gel (AndroGel) treatment maintains beneficial effects on sexual function, mood, lean and fat mass, and bone density in hypogonadal men. Christina Wang, Glenn Cunningham, Adrian Dobs, Ali Iranmanesh, Alvin M. Matsumoto, Peter J. Snyder, Thomas Weber, Nancy Berman, Laura Hull, and Ronald S. Swerdloff. Wang et al. 89(5):2085
[4] Gel Study Group 2000 Comparative pharmacokinetics of two doses of transdermal testosterone gel and testosterone patch after daily application for 180 days in hypogonadal men. Swerdloff RS, Wang C, Cunningham G, Dobs A, Iranmanesh A, Matsumoto A, Snyder P, Weber T, Berman N and TJ Clin Endocrinol Metab 85:4500-4510
[5] Pharmacokinetics of transdermal testosterone gel in hypogonadal men: application of gel to one site versus four sites. Wang C, Berman N, Longstreth JA, Choapoco B, Hull L, Steiner B, Faulkner S, Dudley RE, Swerdloff RS 2000 J Clin Endocrinol Metab 85:964-969
