Trenbolone (Trenbolone Acetate)

Overview and History of Trenbolone

Trenbolone is literally the most powerful anabolic steroid conventionally and commercially available. Unfortunately, Trenbolone has a tendency to at first scare and frighten many individuals who may be researching and reading about this anabolic steroid, or even hearing about it from other individuals. Its an extremely powerful, impressive, and versatile anabolic steroid that tends to suffer from a heavy shroud of rumor, misunderstanding, and mysticism. The fear that many obtain when hearing about this potent steroid can easily be remedied by proper education and understanding, which will serve to bring greater confidence to individuals who may wish to use it, but have previously been too unsure to do so. It is ultimately the fear of the unknown that tends to influence people in a negative manner when it comes to Trenbolone. However, before venturing any further into the details of this anabolic steroid, the following important statement must be made clear: Tren is an intermediate-advanced level anabolic steroid that should never be used by first-timers, beginners, and should never be run in a first-ever anabolic steroid cycle. This steroid should only be utilized and run by intermediate and experienced level tier anabolic steroid users, and it is highly advised that its use only begin to be considered, at the very least, after several basic beginner cycles of Testosterone and other beginner level compounds have been used.

The idea is that any user who feels prepared to venture into Tren use have developed the experience, knowledge, and understanding necessary to run it with very little incidence of risk. Trenbolone is an anabolic steroid that absolutely must be respected, as it is a compound that is associated with side effects and risks unseen with any other anabolic steroid. When utilized irresponsibly, improperly, and without adequate prior education/understanding, it has the potential to cause serious medical health problems with the body.

This anabolic steroid can be found in three different esterified variants: Trenbolone Acetate (the most popular and most widely used Trenbolone ester variant), Trenbolone Enanthate, and Tren Hexahydrobenzylcarbonate. The difference between these three types is simply the half-lives and release times, as determined by the ester that is attached to the parent hormone steroid structure. Esters that are bonded to any anabolic steroid in question do not change the actual properties and effects of the compound except for the half-life of the compound and the release rate. The idea here with different esterified forms of different anabolic steroids is primarily one of personal convenience and preference – some prefer faster acting anabolic steroids with a shorter half-life which necessitates frequent injections, while others prefer the longer half-lives of long estered anabolic steroids that are associated with less frequent injections. The popularity with Tren Ace lies in its fast acting ability due to the small Acetate ester attached, and also the ability for any user to quickly terminate their cycle should any undesirable effects be unbearable for the user. The elimination of administration for Tren Acetate will result in the compound quickly clearing the individual’s body (in a matter of days) leading to a quicker end to any undesirable side effects. The same cannot be said for Tren Enan, for example, as this variant would require two weeks for full clearance of the drug. Tren Acetate holds a half-life of 24 – 72 hours, Trenbolone Enanthate 7 – 10 days, and Tren Hex that of 14 days.

Chemical Characteristics of Trenbolone

Trenbolone is essentially a derivative of Nandrolone with some very significant differences in its chemical properties and strength. Tren and its parent hormone Nandrolone both belong to a class/category of anabolic steroids known as 19-nor compounds, or 19-nors (short for 19-nortestosterone). 19-nor anabolic steroids are labeled as such because they lack the 19th carbon on their structure – this carbon exists on Testosterone and all other anabolic steroids with the exception of 19-nor compounds, such as Nandrolone and Tren. This significantly changes around the properties of an anabolic steroid and makes it a Progestin, which will be discussed further shortly. In Trenbolone, this missing carbon atom at the 19th position (which is in reality a whole methyl group) is replaced by double-bonds between the two carbon atoms that the 19th carbon was originally bound with (this differs from Nandrolone where the lacking 19th carbon is simply replaced with a hydrogen atom instead of double-bonds in Trenbolone’s case). This lack of a 19th carbon is what makes 19-nor compounds very resistant to the aromatase enzyme and therefore very resistant to any estrogen conversion – however, this is not the whole story when it comes to aromatization. Tren also contains modifications at carbons 19 and 11, where one hydrogen atom was removed from each carbon so that carbons 19 and 11 become double-bonded with their neighboring carbon atoms in their respective cycloalkane rings. It is these additional modifications of double-bonds at carbon 19 and 11 that grant Tren to be not just resistant to aromatization, but to become completely immune to it and be unable to interact what so ever with the aromatase enzyme. These modifications are also responsible for the extremely enhanced andrognic strength (its ability to bind at a much greater strength to the androgen receptor)[1] and its ability to remain highly resistant to metabolic breakdown in the body.

Properties of Trenbolone

Trenex 100The chemical modifications described above result in it becoming dramatically more potent of an androgen and an anabolic than its progenitor hormone Nandrolone, or even Testosterone. Testosterone is used as the baseline reference by which all other anabolic steroids are measured against and compared to (much like how the Celsius temperature scale utilizes the boiling and freezing point of water as the base reference for temperature measurement). As such, we can put Trenbolone’s anabolic and androgenic strength into perspective by comparing it to Testosterone. Testosterone possesses an anabolic and androgenic rating of 100 each, respectively. It holds an anabolic and androgenic rating of both 500 each, respectively. In comparison with Testosterone, Trenbolone is five times more anabolic and androgenic in strength than Testosterone. The modification responsible for making it five times stronger than Testosterone is its two double bonds at carbons 19 and 11. Furthermore, for better understanding and perspective, every potential Tren user must realize that in order to achieve the equivalent strength of 200mg, one would have to administer 1,000mg of Testosterone. In order for an individual to achieve the strength of 500mg of Trenbolone, the equivalent of 2,500mg of Testosterone would be required.

This establishes an extremely important and interesting point for every user to remember: Trenbolone is an extremely strong anabolic steroid (the strongest conventionally available) and it is very evident from the numbers presented that in order to achieve impressive performance and physique changes, large doses of Tren are not necessary and small amounts can carry gains a long way.

In terms of its metabolism, it has been previously mentioned that its totally resistant to the aromatase enzyme (which is the enzyme that is responsible for the conversion of aromatizable androgens into Estrogen). Therefore, Trenbolone holds zero Estrogenic activity as it cannot convert into Estrogen in any amount. Its also is completely resistant to the 5-alpha reductase enzyme, which is the enzyme responsible for the reduction of Testosterone into the much stronger androgen Dihydrotestosterone (DHT). Trenbolone here as well is immune from interaction with the 5-alpha reductase enzyme and cannot convert into DHT. However, it must be understood that in its own right is a very androgenic hormone (remember that Trenbolone holds an androgenic rating of 500 versus Testosterone’s androgenic rating of 100).

The extreme strength of the anabolic nature of Tren alongside the fact that it cannot convert into Estrogen are all factors that enable it to be such a versatile and flexible anabolic steroid – it can provide massive strength and lean mass gains in a bulk, and can also be utilized for cutting and fat loss phases as well. These features certainly crush the age-old rumor that this androgen is only useful for fat loss or cutting and/or for a pre-competition phase. These rumors have circulated from individuals within the anabolic steroid using community who are uneducated on its features. This is also very supportive of the fact that there is no reason for utilizing Tren at extremely high and unnecessary doses. This is especially true if an individual is a beginner to use.

Trenbolone Side Effects

The final property of Trenbolone to be covered is that of its commonly labeled ‘harsh side effects’. Side effects will be covered in greater detail later on in the profile, but what must be understood in regards to Tren possessing ‘harsh’ and unique side effects is the fact that it is a 19-nor Progestational compound. Studies have shown that 19-nor anabolic steroids tend to exhibit binding affinity for the Progesterone receptors in the body[2]. Trenbolone in particular possesses very strong binding affinity (much stronger than Nandrolone) for the Progesterone receptor[3]  1. As mentioned above, this is one of the factors involved where it possesses side effects that are almost never seen in other anabolic steroids that are not Progestins. Progestogenic side effects are almost identical to Estrogenic side effects, and they include: severe endogenous Testosterone production shutdown/suppression, gynecomastia, and water retention. It has been determined that the activity of Progestins is closely correlated with the activity of Estrogen in the body.

19-nors being Progestogenic compounds are known to increase a hormone in the body known as Prolactin. Prolactin levels above normal in men often results in side effects such as lactating nipples, erectile dysfunction, anorgasmia (inability to achieve orgasm) and endogenous Testosterone production suppression/shutdown. An interesting point to learn is the fact that Progesterone itself is known to inhibit Prolactin production, and that 19-nors such as Nandrolone and Tren being classified as Progestins should serve to actually suppress Prolactin levels. However, this is not the case as Nandrolone and Trenbolone are not Progesterone themselves – they are anabolic steroids that exhibit Progestogenic activity due to their chemical modifications and it is therefore very possible for these hormones to exhibit activity that is contrary to the activity of a similar hormone or parent hormone. It has been found that Nandrolone and Tren can and do in fact increase Prolactin levels in the body.

trenbolone acetate vialProlactin increases can be controlled either with the use of Prolactin antagonist drugs (such as Cabergoline or Pramipexole), however, prevention of rising Estrogen levels are also an effective method. For one thing, it is strongly speculated that the Estrogen in fact serves as a co-binding factor in the Prolactin receptor expression (PRLR). This can increase an individual’s sensitivity to Prolactin even if Prolactin levels themselves are not high in the body. This is a very sound theory when it is understood that the Estrogen receptor is a causative factor in Prolactin issues. Therefore, controlling Estrogen levels should control the effects of Prolactin. This is the number one reason why the side effects associated with 19-nor compounds (such as Nandrolone) are frequently reported to be far more pronounced and with greater severity when they are used in a high Estrogen environment (whether it is from stacking Nandrolone or Trenbolone with high aromatizable doses of an aromatizable compound, such as Testosterone or otherwise).

It is because of the Progestogenic nature of Nandrolone that it is known to produce severe endogenous natural Testosterone production suppression and shutdown. Therefore, it is recommended that at all times whenever using Nandrolone in a cycle that Testosterone be utilized with it in order to maintain normal physiological function of Testosterone in an environment in which natural Testosterone production has halted or been severely lowered.

It also for often mysterious reasons presents side effects not even seen with its parent hormone Nandrolone. These side effects are the following: increased perspiration (especially at night when sleeping), moderate to severe sleep disturbances and difficulty sleeping (insomnia). These will all be covered in detail in the side effects section of this profile.

Finally, a very important detail for all individuals to understand is that this compound is unapproved by the FDA use in humans in any situation, and it therefore also holds no medical clinical applications at this time. Trenbolone’s main use is for improving the BMI and lean mass in cattle (pigs, beef, etc. through Trenbolone’s very strong nutrient partitioning) so as to produce a larger amount of meat (lean mass) grown on animal farms. Therefore because of the status in regards to human use, the amount of data in regards to Tren and its effects in humans is extremely limited. Therefore it is anecdotal data that is often the only type of data to reference where human use is concerned.

TrenboloneTrenbolone (AKA Finaject)
Chemical Name: 17β-Hydroxyestra-4,9,11-trien-3-one
Molecular Weight: 
270.37 g/mol
Original Manufacturer: 
Half Life: 
3 days (Acetate), 14 days (Hexahydrobenzylcarbonate), 10 days (Enanthate)
Detection Time: 
4 – 5 months
Anabolic Rating: 
Androgenic Rating: 


Trenbolone References:

[1] Unique steroid congeners for receptor studies. Ojasoo, Raynaud, Cancer Research 38 (1978):4186-98

[2] Studies of biological activity of certain 19-nor steroids in female animals. Pincus G, Chang M, Zarrow M, Hafez E, Merril A. December 1956

[3] Characterisation of the affinity of different anabolics and synthetic hormones to the human androgen receptor, human sex hormone binding globulin and to the bovine progestin receptor. Bauer, Meyer et al. Acta Pathol Microbiol Imunol Scand Suppl 108 (2000):838-46.