Trenbolone Acetate


Trenbolone Acetate (commonly abbreviated as Tren Ace, Tren A, or simply as Tren) is the most popular format of Trenbolone in use by bodybuilders and athletes today. Initially, Trenbolone was officially released for a very brief period onto the human prescription market as Trenbolone Hexahydrobenzylcarbonate under the brand name Parabolan, which was manufactured in France. Parabolan was the first and only form of Trenbolone to be ever manufactured and sold for human use. This was for a very short period during the 1990s, however, and towards the late 1990s it was pulled from the market and Trenbolone itself was officially disapproved for human use. To this day, Trenbolone is still only officially utilised as a veterinary medicine exclusively for the purpose of promoting and preserving lean mass in livestock and cattle. It is not currently approved for human use anywhere in the world, but it is under current investigation in clinical studies as a more selective anabolic steroid than others, giving it the potential for medical application[1]. This is therefore a strong indication that Trenbolone might soon see re-entry into the human prescription drug market and re-approval for human use, though it is unknown how long it might be before this happens.

Trenbolone itself is a derivative of Nandrolone, and these two anabolic steroids (Trenbolone and Nandrolone) are classified as 19-nor compounds, meaning they both lack the 19th carbon on their chemical structure (this is what characterizes a 19-nor compound, and this 19th carbon is indeed found on Testosterone and all other anabolic steroids except for those that lack it). Because of this, they are categorized also as Progestins. Although Trenbolone and Nandrolone are distinctly different from Progesterone, they are Progestins and express interaction and activity with the Progesterone receptors in the body. In any case, Trenbolone is further removed from its parent hormone Nandrolone because while the lack of Nandrolone’s 19th carbon is replaced with a hydrogen atom, Trenbolone’s lack of a 19th carbon is replaced with double bonds in order to fill in the void created by the missing 19th carbon. Trenbolone further contains a modification of carbon 11, where a hydrogen atom was removed and the remaining void is once again filled in by double-bonding with its neighbouring carbon atom. What this creates for Trenbolone are three characteristics: the first being a massive increase in the affinity for the androgen receptor, creating a very potent and strong anabolic steroid[2]. The second advantage it creates for Trenbolone is making Trenbolone completely resistant to aromatization into Estrogen. This is a stark difference from Nandrolone, which merely exhibits an increased resistance to aromatization (but it still occurs in smaller amounts). The aromatase enzyme (the enzyme responsible for the conversion of androgens into Estrogen) does not recognise Trenbolone as a proper substrate for chemical reaction. The third characteristic granted to Trenbolone by these modifications is its ability to be highly resistant to metabolism in the body.


Trenbolone Acetate itself was studied in several experiments by Roussel-UCLAF and published in 1967[3]. In the early 1970s, Trenbolone Acetate production was picked up by Hoescht in England and was marketed and sold under the brand name Finajet. Roussel in France sold Trenbolone Acetate as Finaject, and Roussel AG of Germany actually owned and controlled both pharmaceutical corporations. Finaject and Finajet both existed for a short while on the human prescription drug market as well, much in the same manner as Parabolan before they too were discontinued and disapproved for human use. Today, Trenbolone Acetate is used officially in cattle as cattle implants primarily under the brand name of FInaplix tablets/pellets, though other brands exist as well. Trenbolone Acetate’s popularity among bodybuilders and athletes only began during the 1980s, and nearly all of the Trenbolone Acetate used at that time was Finajet and Finaject smuggled into North America from Europe (often in large amounts). It quickly gained status as a very popular anabolic steroid due to its immense potency in anabolism as well as its capability to provide a ‘hard’ look to the physique without any Estrogen conversion and zero water retention as a result. Because of the brief lifespan of Trenbolone Acetate on the human prescription market as mentioned previously, importation of Trenbolone Acetate quickly came to a halt in 1987 just when the drug was reaching extreme popularity and discussion among athletes and bodybuilders.

The late 1980s and early 1990s was a period where many anabolic steroids were purposely discontinued and abandoned (such as Dianabol and several others) due to the increasing anti-steroid hysteria among the US government and the media, which prompted many pharmaceutical companies to discontinue many anabolic steroids that were known to be used and favoured by athletes rather than their medical use. Ironically, however, it was during the end of Finajet and Finaject in Europe that Trenbolone Acetate was brought to the United States in the form of cattle implantation pellets (which must be implanted with a special implantation gun), and the FDA approved this in 1987. It was not long, however, before underground labs (UGLs) and bodybuilders began obtaining these pellets and converting them for use in humans, resulting in injectable preparations or transdermal patches. Some bodybuilders and athletes would also consume the pellets orally, although this was/is a rarer occurrence. However, such a practice is not very far from reality, as Trenbolone exhibits a moderate level of absorption and bioavailability via the oral route due to its very strong resistance to metabolism in the body (higher dosing is required with this method of administration in order to compensate for the percentage lost due to metabolism, however).

It should be noted, however, that there are different brands and variants of Trenbolone Acetate available in the form of cattle implantation pellets that contain other undesirable ingredients. For example, in addition to the different variants of Finaplix tablets (Finaplix-H and Finaplix-S), there exists Revalor and Synovex tablets that contain different concentrations of Estrogen in addition to the Trenbolone Acetate. Such an addition would not be desirable for an athlete or bodybuilder, and this addition of Estrogen is designed for cattle for the purpose of increasing the marbling effect on the meat, and to alter the ratio of lean mass on the animal. Other than this, Trenbolone Acetate today is exclusively an underground product that is either manufactured by underground laboratories or home-brewed by individuals. No pharmaceutical human grade Trenbolone Acetate products exist today as of the writing of this profile (2013).

What Is Trenbolone Acetate and Why Is It So Popular?

Trenbolone Acetate is the short estered variant of Trenbolone, and it tends to be the most popular esterified variant among bodybuilders and athletes. Trenbolone is also available on the anabolic steroid black market in two other formats: Trenbolone Hexahydrobenzylcarbonate, and Trenbolone Enanthate. Trenbolone Acetate is a short-acting variant that exhibits a half-life of 3 days, and must be injected every other day at the very least in order to experience desired performance and physique changes. In comparison, Trenbolone Enanthate exhibits a half-life of approximately 7 – 10 days, and Trenbolone Hexahydrobenzylcarbonate expresses a half-life of approximately 14 days. Trenbolone Acetate tends to be the most popular among the three variants not only due to its widespread availability (especially in the form of Finaplix pellets), but also because its faster acting nature allows users to start and stop use of the drug very fast, with only a matter of days before the hormone completely clears from the body. This is commonly desired by most bodybuilders and athletes due to the fact that Trenbolone is regarded as an intermediate-advanced level anabolic steroid that carries with it potential side effects unseen in other anabolic steroids. It has therefore been labelled as a ‘harsh’ anabolic steroid, and those who use it for the first time normally elect to do so cautiously by utilising Trenbolone Acetate, and if various side effects become too concerning or prominent, the cycle can be halted and Trenbolone Acetate would clear from the body fairly quickly. This is different from the Enanthate or Hexahydrobenzylcarbonate variant, where clearance from the body can require 2 weeks or even longer (for the Hex variant) before the hormone totally clears out of the body.

This hormone is revered for its ability to be utilised for pretty much any goal: strength gaining, bulking, mass gaining, lean mass gaining, cutting, fat loss, etc. Trenbolone exhibits an anabolic rating of 500, which is 5 times the anabolic strength of Testosterone. It also exhibits an androgenic rating of 500, also 5 times the androgenic strength of Testosterone. This makes Trenbolone Acetate a very powerful and formidable anabolic steroid to be respected, where high doses are not required to elicit positive results. Trenbolone Acetate can be utilised to gain large amounts of muscle mass without the water retention and bloating (provided the user is utilising low doses of other aromatizable compounds, and is eating a caloric surplus). It can also be utilised to lean out the physique and shed body fat faster than any other anabolic steroid if the user engages in a caloric deficit and appropriate training regime. Because of Trenbolone’s extremely potent nutrient partitioning capabilities, it can be used to effectively put on significant mass or be used to cut body fat, and is considered an essential addition to pre-contest cycles. It is often referred to as “the nectar of the Gods” due to its incredible capabilities.

Tren Acetate tends to bring with it an aura of intimidation to many users, however. This is due to the lore and legend surrounding some of its unique and often termed ‘harsh’ side effects. This will be covered very shortly, but it should be established here and now to all readers that although there is some truth to Trenbolone’s legend of being a ‘harsh anabolic steroid’, there is much exaggeration and myth surrounding many of these claims and stories as well.

How Does Trenbolone Acetate Work and How Is It Best Used?

As previously mentioned, Trenbolone Acetate is perhaps the most versatile anabolic steroid next to Testosterone itself. It can be utilised in any cycle type, and compliments any other compounds very well. It should always be utilised with Testosterone, however, as its Progestogenic activity can cause impairment of the libido and other proper functions that Testosterone is responsible for governing. Therefore, many users who elect to use Tren Ace on its own commonly experience sexual dysfunction and anorgasmia (the inability to orgasm). Testosterone even at a TRT (Testosterone Replacement Therapy) dose of 100mg per week should suffice in assisting the body supportively during Tren use.

Trenbolone Acetate Side Effects

Trenbolone Acetate carries with it many of the standard potential side effects that all anabolic steroids in general carry with them (for example: negative cholesterol alterations, cardiovascular effects, endogenous Testosterone and HPTA suppression/shutdown, etc.). However, what should be the focal point here of this section of this profile are the unique side effects that are associated with Trenbolone, which are often referred to as ‘harsh’ and come with plenty of absurd lore, legend, myth, and rumour. Upon first use of Trenbolone Acetate in the 1980s, not much knowledge was known about it and therefore many athletes and bodybuilders were left up to their own suspicions and curiosity, but today the amount of scientific and clinical knowledge is far greater, which should clarify many of the myths and rumours surrounding Tren.

Unique side effects associated with Trenbolone Acetate include a moderate to severe coughing fit during and shortly after injecting the compound. This tends to occur more frequently with Trenbolone Acetate than it does with other forms of Trenbolone, likely due to the faster release of the compound and other unknown factors. The cause of this ‘Tren cough’ is largely unknown, but some valid and accurate hypotheses include the fact that Trenbolone itself causes varying degrees of anaphylactic reactions in the bronchial pathways, as well as some of the compound seeping into punctured capillaries/veins during the injection, which irritate the lungs. What results is a coughing fit that can range from very mild to severe and lasts only several minutes. Injecting the compound slowly tends to eliminate or reduce the intensity of the coughing, and many times this does not occur at all. It should be noted that a coughing fit can occur from any anabolic steroid injected that seeps into ruptured blood vessels, and that a coughing fit does not mean that the Trenbolone is necessarily ‘legitimate’ or ‘good to go’.

Trenbolone is known for causing severe sweating, especially during nighttime sleeping. This is also accompanied by insomnia, either in the form of being unable to fall asleep or the intermittent waking throughout the night accompanied with tossing and turning. The insomnia, commonly dubbed as ‘Trensomnia’, is thought to be due to Trenbolone’s increased influence and activity on the nervous system than most other anabolic steroids, which can tend to increase the excitability of the nervous system and disrupt quality sleep patterns. The cause of the severe perspiration and sweating associated with Tren Acetate is currently unknown, though some hypotheses claim that the sweating is induced by Trenbolone’s capability to increase the metabolism (and thus heat generation) at certain times of the day.

Lastly, Trenbolone is known for its ability to induce larger amounts of aggression, anger, and impatientness in some users. This is due to Trenbolone’s increased activity on the central nervous system, and is due also in very large part to its extremely strong androgenic strength. It is highly advised that those who have problems with their temper or patience to take responsible action and avoid the use of Trenbolone at all costs, or learn to exhibit self-control when one’s anger, temper, or patience gets the best of them. It is irresponsible to utilise a very strong compound such as Trenbolone (and knowing full well all of its potential effects) and allow oneself to get angry and land in trouble, and instead blaming the anabolic steroid rather than themselves for exercising poor self-responsibility. Tren is a drug, a hormone to be respected. Respect the hormone and it will respect you.


Trenbolone References:

[1] Tissue selectivity and potential clinical applications of Trenbolone (17beta-hydroxyestra-4,9,11-trien-3-one): A potent anabolic steroid with reduced androgenic and estrogenic activity. Yarrow JF, McCoy SC, Borst SE. steroids. 2010 Jun;75(6):377-89. doi: 10.1016/j.steroids.2010.01.019. Epub 2010 Feb 4.

[2] 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.

[3] J. Mathieu, Proc. Intern. Symp. Drug Res. 1967, p 134. Chem. Inst. Can., Montreal, Canada.