Trenbolone was first synthesized in 1963 by Velluz et al. The drug appears to have been an early development project of Roussel-UCLAF. By the early 1970s, it was being sold as an injectable (trenbolone acetate) in England by Hoechst as Finajet, and in France as Finaject by Roussel. Roussel AG in Germany was a parent to both companies. Trenbolone acetate is a drug of veterinary medicine, although a longer-acting ester of trenbolone was once sold for human consumption as well. Trenbolone acetate is used, almost exclusively, to increase the rate of weight gain and improve feed efficiency of cattle shortly before slaughter. Essentially, the drug is utilized to increase product profitability, as measured in total pounds of salable meat. It is generally used right up to the point of slaughter, with no withholding period. Meat products sold in many areas of the world will often contain small amounts of residual trenbolone metabolites as a result of this practice.
Trenbolone acetate first became popular among U.S. bodybuilders during the 1980s, a time when the drug was being smuggled in from Europe in high volume. It was identified (rightly so) as a powerful anabolic and androgenic agent, and quickly became a drug of choice among American competitive bodybuilders. Although extremely hot for a brief period of time, the supply of trenbolone acetate ended abruptly in 1987, as Hoechst-Roussel decided to voluntarily discontinue the sale of all injectable forms of this medication. Although unconfirmed, the growing public concern about sports doping likely had much to do with this decision, as the discontinuation of “controversial” steroids was very common during the late 1980s and early 1990s. This event marked the end of legitimate medicines containing trenbolone acetate for injection.
Around the same time as we were seeing the demise of Finajet and Finaject, Hoechst-Roussell was introducing trenbolone acetate to the U.S. market as Finaplix cattle implant pellets. This came subsequent to the FDA’s approval for such products in 1987. The pellets were designed for subcutaneous implantation into the ear of the cattle with a handheld implant gun, and are far too large to be implanted in humans without minor surgery. Remarkably, trenbolone acetate pellets are exempt from U.S. controlled substance laws. This is presumably to make it easy and affordable for livestock owners to have access to the growth-promoting agent. If a veterinarian were needed every time these products were to be used, they might be too troublesome or cost-prohibitive to consider. Admittedly, since these products come in the form of pellets, they are not in a form suitable for human consumption either, making their exemption seem a little more reasonable than at first glance.
The human administration of Finaplix pellets can be difficult to accomplish, but it is still widely done. Most commonly, two to four implant pellets are ground up and mixed with a 50/50 water and DMSO solution, which is applied to the skin daily. This home-brew transdermal mix is effective, but also tends to carry a strong odor of garlic (an effect of the DMSO). Others simply grind up a few pellets with the back of a spoon and inhale (snort) them. Here, the drug enters the bloodstream through the mucous membrane, a poor but still useful means of delivery for steroid hormones. Those who have tried this often claim it is not as irritating as they had imagined it would be. Alternately, some athletes opt to simply consume the drug orally. Although not an ideal mode of delivery, trenbolone displays a moderate level of oral bioavailability and can be used in this manner given adequate dosing.
More adventurous individuals have made it a practice to mix their own injections with Finaplix. The pellets are ground into a fine powder (usually anywhere from 2 to 6 pellets), and then are added to sterile water, propylene glycol, or an oil-based injectable steroid or veterinary vitamin. This is usually repeated twice weekly, although some do manage to undertake this practice more frequently. Since this is not being done in a controlled sterile environment, however, one is obviously risking infection (or worse) by doing this. Starting in the late 1990s, some stores began selling kits that contain all the necessary ingredients to separate the binders from the active steroid and brew a relatively pure injectable. These kits have grown in popularity over the years, and are usually reviewed favorably, although they are not considered a substitute for sterile pharmaceutical medications.
Finaplix® is presently available in the U.S. and some markets abroad, although it is now being sold by Intervet instead of Hoechst-Roussel Agri-vet. This product comes in two forms, Finaplix-H and Finaplix-S, which denotes if the product was intended for a Heifer or a Steer respectively. The total dosages of both products are different, with the “H” version containing 100 20 mg trenbolone acetate pellets (2,000 mg) and the “S” version only 70 (1,400 mg). Ivy Animal Health (U.S.) has introduced two competing products of equivalent makeup as well, sold as Component-TH and Component-TS. There are also the Revalor and Synovex+ brands that contain trenbolone acetate with an added (usually unwanted) dose of estrogen. Additionally, although no other legitimate medicines containing trenbolone acetate exist, the drug is produced (for injection and oral use) by a number of export and underground steroid manufacturers.
Trenbolone acetate is available in select veterinary drug markets. It generally comes in the form of implant pellets containing 20 mg of trenbolone acetate each. Injectable preparations containing 30 mg/ml of steroids in oil were formerly sold.
Trenbolone is a modified form of nandrolone. It differs by the introduction of double bonds at carbons 9 and 11, which inhibit aromatization (9-ene), increase androgen-binding affinity,1 and slow its metabolism. The resulting steroid is significantly more potent as both an anabolic and an androgen than its nandrolone base. Trenbolone acetate contains trenbolone modified with the addition of carboxylic acid ester (acetic acid) at the 17-beta hydroxyl group so that the free steroid is released more slowly from the area of injection.
Side Effects (Estrogenic)
Trenbolone is not aromatized by the body, and is not measurably estrogenic. It is of note, however, that this steroid displays a significant binding affinity for the progesterone receptor (slightly stronger than progesterone itself ).2 The side effects associated with progesterone are similar to those of estrogen, including negative feedback inhibition of testosterone production and enhanced rate of fat storage. Progestins also augment the stimulatory effect of estrogens on mammary tissue growth. There appears to be a strong synergy between these two hormones here, such that gynecomastia might even occur with the help of progestins, without excessive estrogen levels. The use of an anti-estrogen, which inhibits the estrogenic component of this disorder, is often sufficient to mitigate gynecomastia caused by progestational anabolic/androgenic steroids. Note that progestational side effects are more common when trenbolone is being taken with other aromatizable steroids.
Side Effects (Androgenic)
Although classified as an anabolic steroid, trenbolone is sufficiently androgenic. Androgenic side effects are still common with this substance and may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Women are also warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement. Additionally, the 5-alpha reductase enzyme does not metabolize trenbolone,3 so its relative androgenicity is not affected by finasteride or dutasteride.
Side Effects (Hepatotoxicity)
Trenbolone is not c-17 alpha alkylated, and is generally not considered a hepatotoxic steroid; liver toxicity is unlikely. This steroid does have a strong level of resistance to hepatic breakdown, however, and significant liver toxicity has been noted in bodybuilders abusing trenbolone. Although unlikely, hepatotoxicity cannot be completely excluded, especially with high doses.
Side Effects (Cardiovascular)
Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Due to its non-aromatizable nature and strong resistance to metabolism, trenbolone has a moderate to strong (negative) impact on lipid values and atherogenic risk. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.
To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.
Side Effects (Testosterone Suppression)
All anabolic/androgenic steroids, when taken in doses sufficient to promote muscle gain, are expected to suppress endogenous testosterone production. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention. In experimental studies, trenbolone was determined to be approximately three times stronger at suppressing gonadotropins than testosterone on a milligram for milligram basis. The above side effects are not inclusive.
Trenbolone acetate was never approved for use in humans. Prescribing guidelines are unavailable. An effective dosage for physique- or performance-enhancing purposes generally falls in the range of 100-300 mg per week, taken for 6 to 8 weeks. Due to the short-acting nature of acetate esters, the total week’s dosage is subdivided into 2-3 smaller applications. Effective oral doses tend to fall in the range of 100-200 mg per day, taken for no longer than 6-8 weeks to minimize any potential hepatic strain. This level is sufficient to notice strong increases in strength and lean tissue mass, with a low level of unwanted side effects. Lack of estrogenic activity has made trenbolone very appealing for competitive athletes looking to shed fat, while at the same time trying to avoid water retention. Here, trenbolone may provide the high androgen content needed in order to elicit a very hard, defined physique. While it is a noteworthy hardening agent, this is not the only benefit of trenbolone acetate. It is also a strong anabolic, with muscle-building properties often compared to testosterone and Dianabol, but without the same level of water retention. This may be a little generous of a description, as its lack of estrogenic activity does seem to hurt this agent in its abilities to promote muscle mass gains.
While trenbolone is often recommended as a great addition to a mass cycle, it is rarely reported to be a very powerful agent when used alone. Results are most often reported as moderate lean tissue growth accompanied by exceptional hardening and fat loss. Although perhaps it is not quite as potent as the more estrogenic bulking agents if the sheer mass is the goal, trenbolone is still a better builder milligram for milligram than nandrolone, and likely the most anabolic of all the non-estrogenic commercial steroids.
For stacking, trenbolone is a very versatile steroid and seems to work exceptionally well with other agents for both bulking and cutting purposes. For cutting, bodybuilders often stack it with a mild anabolic like Winstrol® or Primobolan®. Without extra water beneath your skin, the mix will elicit a very solid, well-defined hardness to the physique. For lean mass gains, Deca-Durabolin® or Equipoise® are popular additions. Here again, trenbolone will greatly enhance and solidify the new muscle growth. When looking purely for mass, Trenbolone pairs well with testosterone, Anadrol 50®, or Dianabol. The result is typically the rapid and substantial gain of somewhat solid muscle mass. In the Underground Steroid Handbook II, Dan Duchaine describes the mix of trenbolone, testosterone, and Anadrol as the “Most Effective” stack for men, and states, “I’ve not encountered any other stack that will put weight and strength on like this one.” This particular drug combination has subsequently become quite popular.
Trenbolone acetate was never approved for use in humans. Prescribing guidelines are unavailable. This agent is not recommended for women for physique- or performance-enhancing purposes due to strong androgenic nature and a tendency to produce virilizing side effects.
Pharmaceutical preparations containing trenbolone acetate remain scarce. The bulk of the supply for this compound comes from underground steroid manufacturers.
- Unique steroid congeners for receptor studies. Ojasoo, Raynaud. Cancer Research 38 (1978):4186-98.
- 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.
- Disposition of 17 beta-trenbolone in humans. Spranger, Metzler. J Chromatogr 564 (1991):485-92.