The Many Faces of Trenbolone


You can find many articles on the internet about Trenbolone and mostly the writers will tell you that all Trenbolones are equal (they have the same parent compound, right?). The only difference is their half-life due to their estrification and therefore also the active compound will differ due to the molecular weight of the estrification.

Confusing, maybe but during this article I’ll try to explain clearly for all to understand.

It’s not only the esterifications that are responsible for the strength effect of these compounds, but also the carriers, the solvents, co-solvents and the concentration. Where one of these Trenbolones like the Trenbolone Enanthate is effective in milligrams per millilitre, another like Metribolone is already active in micrograms.

Very confusing is also that some of these compounds have different names and some people on the net just are mistaken or mixed up. Trenbolone is available as:

Trenbolone base

Like all other bases, trenbolone base has no ester. This causes a rapid release of the compound upon injection. Of course this allows the full effects of the compound to be experienced much quicker than with an estrified compound, but the same goes for the side effects. Administration of the compound and the lack of an ester requires frequent injections, most often daily or twice per day. The active life of the compound is about 24 hours. The active life highly depends on the carrier, but more about that later.
Trenbolone Acetate

Active life of this ester is about 2-3 days. Like the Trenbolone base, it must be administered frequently but this usually entails injections daily or every other day. This is probably the most popular ester of trenbolone, as the drug demands that inexperienced users administer something that can be discontinued rapidly if they react poorly. Coupled with the fact that it can be injected only every other day, it is obvious why many users prefer acetate.

Trenbolone Acetate–injectable version (Finaject and Finajet)

Trenbolone first gained fame under the brand names Finaject and Finajet, an oil based injectable veterinary steroid containing 30milligrams per ml of trenbolone acetate. Both of these product were marketed for use in food production animals, like cattle, pigs and sheep. Numerous studies have proven the effectiveness of trenbolone, when used with an estrogen, in improving quality weight gain in these animals while they ate less grain and feed, most studies noted a significant increase in muscle size, with a decrease in fat content, improving the “carcass quality’ (meaning better steaks) in the trenbolone-treated animals.

By the early 1970′s, trenbolone acetate was being sold in England by Hoechst as Finajet, and in France as Finaject by Roussel became popular among U.S. bodybuilders during the 1980′s, a time when the drug was being smuggled in from Europe in high volume. Bodybuilders referred to it as “Fina.” It was produced with a short acting ester (acetate), so its effect lasts only a short time and frequent administration is necessary. Finaject was an injectable steroid of veterinary medicine, which became extremely popular in bodybuilding and powerlifting during the 1980’s. HoechstRoussel discontinued sale of all injectable Trenbolone Acetate in 1987.
Trenbolone Acetate–pellet form (Finaplix)

Finaplix was a veterinary cattle implant, which contained the potent androgenic steroid Trenbolone Acetate. Once Finaject and Finajet were no longer manufactured, bodybuilders began using Finaplix to make topical or injectable versions of Trenbolone Acetate. Today, cattle implants have become designer products with varied doses and combinations of estrogenic and/or androgenic (trenbolone) agents. So, the process of converting cattle implants to useful versions of trenbolone acetate has become more difficult since one must separate the trenbolone from the other additives present in the cattle implants before using it.

Trenbolone Hexahydrobenzylcarbonate – Trenbolone Cyclohexylmethylcarbonate – Parabolan

Trenbolone Hexahydrobenzylcarbonate and Trenbolone Cyclohexylmethylcarbonate are exactly the same substances.

Hexahydrobenzylcarbonate ester is just another name for cyclohexylmethylcarbonate ester (Its Bill Roberts that frequently used this ester name when referring to Parabolan).

Parabolan, was known as one of the strongest steroids available on the black market. It became harder and harder to find, until eventually it was discontinued in 1997. Negma, out of France, was the sole company who produced the anabolic steroid. Parabolan came in 1.5ml amps, and each ampule contain 76mgs of the steroid. The steroid was so popular on the black market, there were still fakes of it going around up to ten years after it was discontinued. And even now you can find copies on the black market.

Once trenbolone hexahydrobenzylcarbonate was discontinued, steroid users in search of trenbolone turned to Finaject, a veterinary steroid, then to Finaplix, an implant used in cows. Users, through a process would separate the steroid from the glue and bindings, and create an injectable solution. It was often dosed at 76mgs, same as Negma’s Parabolan. However, trenbolone acetate and trenbolone hexahydrobenzylcarbonate were slightly different in terms of half-life. The acetate ester is much faster acting and needs to be injected, at minimum, every other day. And as powerful as trenbolone acetate is, many users who have used trenbolone acetate, trenbolone enanthate and Parabolan will say the latter was much and much stronger. Parabolan (trenbolone hexahydrobenzylcarbonate) is available from Chinese and Indian API (raw powder) sources and though extremely expensive, most competitive bodybuilders insist on using this compound in their contest preparation.

Today, we also have trenbolone enanthate available in black markets. Trenbolone enanthate is even more comparable to trenbolone hexahydrobenzylcarbonate because it has a much longer half-life and doesn’t need to be injected quite as often as trenbolone acetate. Trenbolone enanthate is usually injected every 5-7 days.
Trenbolone Enanthate

As stated above it is quite similar to Hexahydrobenzylcarbonate (Cyclohexyl-methylcarbonate) in terms of active life, although it is reportedly a bit longer acting. However, the major difference, beside potency, between enanthate and Hexahydro-benzylcarbonate (aka Cyclohexylmethylcarbonate) is the weight of the ester. This difference is discussed below.
Metribolone – Methyltrienolone – Oral Parabolan

Accourding to VIDA, Oral Trenbolone Metribolone(Methyltrienolone) has an androgenic/anabolic ratio of 6.000-7.000/12.000-30.000 as compared to Trenbolone Acetate/Enanthate 500/500. The effective dose of Metribolone lays between 0.1 and 1.0 mg steroid drug per day in normal adults. Kruskemper et all. Steroids. 1966 Jul;8(1):13-24

Methyltrienolone as an orally active anabolic agent has been tested with regard to its influence on liver function. As measured by multiple parameters (BSP retention; total bilirubin; activities of transaminases, alkaline phosphatase and cholinesterase in serum; activity of proaccelerin in plasma) methyltrienolone turned out to be very active as to causing biochemical symptoms of intrahepatic cholestasis. To avoid the first pass through the liver and to create an even stronger anabolic effect Hard Core Labs created an subcutaneous Metribolone. More about this later in this article.

Mixed compounds …The differences between the esters

The most important difference between the esters is whether it is a short acting ester or a long lasting ester. The next most important difference is the weight of the ester. As mentioned under the Trenbolone Cyclohexyl-methylcarbonate, the relative potency of each ester of trenbolone is partially dependent on the weight of its ester.

The main difference between different esters is simply the number of carbon atoms in the ester. Esters and their active life are pretty much determined by the number of carbon atoms attached to a compound. Acetate has two carbon atoms, enanthate has seven, and obviously a base has no extra weight added to it. Cyclohexylmethylcarbonate is the heaviest of the esters having eight carbons attached, along with an extra oxygen. However the difference in the potency and bioavailability of these various esters is, intra-individual, very different.

Underground Mistakes

What we see here are Underground made products that are degraded. This can be due to various reasons. The first Underground Labs extracted their trenbolone from veterinary pellets. They were used to bake their vials, after closing them, in the oven. If the temperature is too high the compound will degrade. Some UG labs use to much solvents or mix the wrong way, the powder will degrade and later you’ll notice it in the vials as dark spots. Roussel Uclaf did a lot of stability studies. I’ll post a few here.

As should be clear to you by now is, that not only baking all of the power out of the compound, but also exposing it to light will degrade the product.

Then of course you need a pure substrate to produce a good product. On the left you see an odd coloured powder that produced a very dark solution. On the net known as “Black Tren.”

Trenbolone actate is a steroid used by farmers to improve the efficiency of meat production (muscle growth) in cattle, poultry and sheep. And it increases appetite.

Trenbolone is neither affected by aromatase or 5alpha-reductase. This means it becomes neither weaker nor stronger in androgen responsive target tissues, and is a trait usually shared by DHT (Dyhydrotestosterone) derived steroids; Since Trenbolone, it is not actually DHT derived but rather, it is derived from 19-Nor-Testosterone (Nandrolone). Trenbolone has no estrogenic activity (it may actually reduce serum estradiol levels in the body), is a very strong anabolic and androgenic compound (5x stronger than testosterone in both categories!), and it binds well to the androgen receptor. Actually, binding “well” to the androgen receptor is quite an understatement. There is no injectable AAS in our arsenal that binds to the androgen receptor (AR) as well as Trenbolone does. This is probably a major reason that Trenbolone (Parabolan) was so sought after for use as a pre-contest agent. Androgen Receptors are found in fat cells as well as muscle cells, and we all know that they act on the AR in muscle cells to promote growth, but they androgens act directly on the AR in fat cells to affect fat burning. The stronger the androgen binds to the A.R, the higher the lipolytic (fat burning) effect on adipose (fat)tissue. As if that’s not enough good news, some steroids even increase the numbers of A.R. in muscle and fat to speculate that this fat losing effect would be amplified with the concurrent use of other compounds, such as injectable testosterone. This fat burning capacity is why Trenbolone is called “the poor men’s growth hormone”

Another mechanism whereby Trenbolone causes muscle accumulation and fat loss is its ability as a nutrient partitioning agent. Basically, what this means is that while using Trenbolone, more of the food you eat will become muscle and less (if any) will become fat.

Farmers gave their livestock Trenbolone acetate due to its ability to improve feed efficiency and mineral absorption in animals, feed efficiency is a measurement of how much of an animals diet is converted into meat, the less food it takes to produce meat, the higher the efficiency.

Really, as you can see, most of Trenbolone ´s cult reputation is well deserved… And as if that’s not enough, Trenbolone noticeably increases the level of the IGF-1 within muscle tissue, which in itself is an extremely anabolic hormone. And, it’s worth noting that not only does it increase the levels of IGF-1 in muscle over two fold, it also causes muscle satellite cells (cells that repair damaged muscle) to be more sensitive to IGF-1 and other growth factors. Trenbolone ( any version) would be synergistic within a cycle containing any form of injectable IGF-1.

Trenbolone also happens to bind quite strongly to the glucocorticoid receptor as well, and this in turn imparts a nice anti-catabolic effect… which in part may help to explain why low(ish) doses of it seem to work nicely, as well as why it aids fat loss. You see, glucocorticoid hormones send a message to muscle cells to release stored protein (this is called catabolism), which is exactly the opposite of what we want.

This drug stacks well with mostly everything especially Testosterone (actually, if you want to avoid sexual dysfunction, stacking it with test is necessary). I have also found it to be a great addition to a stack containing Boldenone as well.

Some underground laboratories like Hard Core Labs (HCL) sell the injectable versions of oral steroids like Ana-ject, D-bol-ject and MT-DMN that contains metribolone (MT). A user was so kind to send me his bloodvalues so we are able to compare the real bloodvalues to those many guru’s like William Llewellyn expected due to scientific data. Later in this article I’ll post more about the bioavailability from oral to subcutaneous administration.

Side effects

  • Insomnia (Trensomnia)
  • Uncontrolable coughing after injection (Tren Cough)
  • Excess Sweating
  • Night Sweats
  • Rapid Heart Rate
  • Anxiety
  • Loss of Libido
  • Erectile Dysfunction (Tren-dick or Deca-dick)
  • Increased aggression and irritability


Recent studies that compare Trenbolone with Testosterone and SARM for HRT

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 et all. 2010

Recently, the development of selective androgen receptor modulators (SARMs) has been suggested as a means of combating the deleterious catabolic effects of hypogonadism, especially in skeletal muscle and bone, without inducing the undesirable androgenic effects (e.g., prostate enlargement and polycythemia) associated with testosterone administration. 17beta-Hydroxyestra-4,9,11-trien-3-one (trenbolone; 17beta-TBOH), a synthetic analog of testosterone, may be capable of inducing SARM-like effects as it binds to androgen receptors (ARs) with approximately three times the affinity of testosterone and has been shown to augment skeletal muscle mass and bone growth and reduce adiposity in a variety of mammalian species. In addition to its direct actions through ARs, 17beta-TBOH may also exert anabolic effects by altering the action of endogenous growth factors or inhibiting the action of glucocorticoids. Compared to testosterone, 17beta-TBOH appears to induce less growth in androgen-sensitive organs which highly express the 5alpha reductase enzyme (e.g., prostate tissue and accessory sex organs). The reduced androgenic effects result from the fact that 17beta-TBOH is metabolized to less potent androgens in vivo; while testosterone undergoes tissue-specific biotransformation to more potent steroids, dihydrotestosterone and 17beta-estradiol, via the 5alpha-reductase and aromatase enzymes, respectively. Thus the metabolism of 17beta-TBOH provides a basis for future research evaluating its safety and efficacy as a means of combating muscle and bone wasting conditions, obesity, and/or androgen insensitivity syndromes in humans, similar to that of other SARMs which are currently in development.

17β-Hydroxyestra-4,9,11-trien-3-one (trenbolone) exhibits tissue selective anabolic activity: effects on muscle, bone, adiposity, hemoglobin, and prostate. Yarrow et al 2011

Selective androgen receptor modulators (SARMs) now under development can protect against muscle and bone loss without causing prostate growth or polycythemia. 17β-Hydroxyestra-4,9,11-trien-3-one (trenbolone), a potent testosterone analog, may have SARM-like actions because, unlike testosterone, trenbolone does not undergo tissue-specific 5α-reduction to form more potent androgens. We tested the hypothesis that trenbolone-enanthate (TREN) might prevent orchiectomy-induced losses in muscle and bone and visceral fat accumulation without increasing prostate mass or resulting in adverse hemoglobin elevations. Male F344 rats aged 3 mo underwent orchiectomy or remained intact and were administered graded doses of TREN, supraphysiological testosterone-enanthate, or vehicle for 29 days. In both intact and orchiectomized animals, all TREN doses and supraphysiological testosterone-enanthate augmented androgen-sensitive levator ani/bulbocavernosus muscle mass by 35-40% above shams (P ≤ 0.001) and produced a dose-dependent partial protection against orchiectomy-induced total and trabecular bone mineral density losses (P < 0.05) and visceral fat accumulation (P < 0.05). The lowest doses of TREN successfully maintained prostate mass and hemoglobin concentrations at sham levels in both intact and orchiectomized animals, whereas supraphysiological testosterone-enanthate and high-dose TREN elevated prostate mass by 84 and 68%, respectively (P < 0.01). In summary, low-dose administration of the non-5α-reducible androgen TREN maintains prostate mass and hemoglobin concentrations near the level of shams while producing potent myotrophic actions in skeletal muscle and partial protection against orchiectomy-induced bone loss and visceral fat accumulation. Our findings indicate that TREN has advantages over supraphysiological testosterone and supports the need for future preclinical studies examining the viability of TREN as an option for androgen replacement therapy.


Keep in mind that it is done on Rats, so there is no exact medical conversion into comparable human doses without knowing the differences in metabolism/clearance of given compound/metabolites.

Mathematically, however, the conversion factor for Rat to Human is defined by the FDA to be 0.162 The conversion from Mice to Human is .081

This study does not appear to list dosages in the mg/kg range, just a total dose per Rat so we would need to figure this out.

Avg 3 month male rat weight is approx 300-500 grams. Let’s just say 500 since it is easy to use 1/2 kilogram (500g) as the weight. The low dosage in the study is 1mg/week Trenbolone per Rat, which appears to be apprx 2mg/kg/week.

For a 220lb (100kg) person that equates to 200mg/week, and then multiply by the final (Rat-Human) conversion factor of .162 and we get 32.4mg/week of Trenbolone.

Conversions for the low/med/high TREN doses in the study (rats) and approx mathematical human values:
Values for a 100kg Person via animal-human mathematical conversion

Low Dose: 32.4mg/week (Converted from 1mg/week/rat)

Med Dose: 113.4mg/week (Converted from 3.5mg/week/rat)

High Dose: 226.8mg/week (Converted from 7mg/week/rat)

Anyhow, I stress that these conversions are more mathematical than medical in nature.


We’re attempting to estimate what doses of trenbolone-enanthate (in humans) would be equivalent to the doses the researchers administered to their rodents. I have not previously attempted to determine drug dose conversions between species, so I am assuming these numbers are indeed correct. With that assumption, the math appears correct; although from my conversations with the researcher his animals weighed more in the 275-300g range. Also, please consider that they obtained a highly myotrophic effect from the “half-low” dose of TREN (0.5mg/week).

Another, perhaps more important consideration, is that FDA provides drug dose conversion factors to determine maximum recommended starting doses (MSRDs) for clinical trials based on the ‘no observed adverse event level’ (NOAEL) following pre-clinical toxicology studies. It’s my understanding they did not perform any toxicological assessments of this agent, they simply demonstrated its myotrophic efficacy. Clearly, future pre-clinical work is required before advancing this agent to clinical testing.

Related article: The many faces of trenbolone.


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