Methyltrienolone (Metribolone)


methyltrienolone Metribolone (methyltrienolone R1881) [ 17-beta-hydroxy-17-methyestra-4,9,11-trien-3-one ], is a powerful non-aromatizable an androgen, which is structurally similar to trenbolone and is called “oral trenbolone” (there is also an injectable version): it is actually methylated trenbolone at the C-17 alpha position, and like trenbolone, it does not aromatize at any dosage. In fact, it would be more accurate to say that Trenbolone is Metribolone clarified by methylation in the C-17 alpha channel (Trenbolone was only sold in 1976).


Methyltrienolone binds strongly to the androgen receptor (AR) and is a more potent androgen receptor agonist (activator) than trenbolone or DHT and its derivatives: as is often the case, 17-alpha methylation involves not only the ability of the molecule to pass more or less intact through the liver, other modifications occur, in this particular case, extremely affinity for androgen receptors and bond stability (as mentioned earlier, from this point of view, it is considered the most powerful AAS and therefore is used in the laboratory to determine the strength of affinity for the AR receptors of other AAS). In addition, the affinity for androgen-binding proteins (which prevent the biological activity of AAS) is even lower than that of trenbolone, almost zero.

But also the strength of the signal emitted by the molecule, once bound to the receptor site, is enormously enhanced, possibly due to the stability of the binding to the androgen receptor: for some time there has been talk of an androgenic and anabolic strength equal to 10 or 100 times Trenbolone (empirical estimates). Julius Vida, already in 1969 in his fundamental book Androgens and Anabolic Agents: Chemistry and Pharmacology, claims that in a laboratory he measured anabolic strength equal to 30,000 times (not a mistake) and 12000 times the androgenic strength in relation to methyltestosterone 100: 100 (which is 150: 130 compared to testosterone). This means that one molecule, mg per mg, is about 72 times more anabolic and 100 times more androgenic than trenbolone . The effective dosage for this molecule starts at only 25 mcg / day, the advantage of this molecule is to avoid receptor saturation by avoiding high doses, great.

Steroid experts William Llewellyn and Patrick Arnold describe methyltrienolone as one of the “most powerful” anabolic steroids ever made. It is also one of the most hepatotoxic AAS ever produced. Originally developed by Roussell-UCLAF in the 1960s, the hepatotoxicity of Metribolone prevented its market launch. Bill Roberts compared the toxicity of methyltrienolone to toxicity that should be taken with high doses of Anadrol in combination with high doses of halotestin. Due to the very low dosages required for the molecule to exert its effect, hepatotoxicity is manageable and reduced, especially when taking N-ademetionine (Samyr).

According to Patrick Arnold, many athletes used methyltrienolone in the 1990s and successfully passed drug tests due to the very small amount of this steroid needed to improve performance. He was somewhat surprised that methyltrienolone was detected by anti-doping tests, which caused a scandal that affected some Greek athletes. This event showed that anti-doping tests have been significantly improved upon the discovery of this molecule. 11 Greek weightlifters and 4 Greek athletes tested positive for methyltrienolone ahead of the 2008 Beijing Olympics. .
gestrinone-thg Patrick Arnold is the organic chemist who developed the tetrahydrogestrinone (THG), once undetectable by AAS tests. THG is a modified form of methyltrienolone. In March 1997, Patrick Arnold published a detailed method for the synthesis of methyltrienolone from the readily available veterinary product Finaplix-H (trenbolone acetate granules for subcutaneous administration in cattle).

To summarize and given the typical characteristics of trenbolone, metribolone has the following characteristics:

  • 12,000 androgen / 30,000 anabolic versus methyltestosterone
  • Strong AR, but with the addition of the ability to establish a direct connection of an agonist with progestogen receptors and an agonist feedback with cortisol receptors;
  • Not fully aromatized, even if not reduced to 5-alpha due to the double bond in C9-C10 introduced compared to nandrolone
  • High hepatotoxicity when certain dosage thresholds and time of administration are exceeded (also dependent on feeding): hepatotoxicity is kept to a minimum, as with other C-17-methylates, relative to (mg x mg)), less in absolute terms, given the size of the doses. With excessive doses, liver damage is not only a danger but a reality.
  • His active life is approximately 24 hours (about the same as the injectable version).

It is safe to say that the claims of William Llewellyn and Patrick Arnold that Metribolone is the most powerful anabolic agent ever made are completely correct.

Hopefully once again it was helpful to clarify some of the concepts behind chemistry applied to bodybuilding.

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