Boldione (1,4-androstadiene-3,17-dione) is the lead innovation to arise out of the next generation of orally active prohormones. It is a direct precursor to the anabolic steroid boldenone, and displays a level of oral bioavailability far superior to any other compound, including the new 1-androstenes. If you are unfamiliar with boldenone, it is an anabolic steroid most often found in injectable form as a veterinary medication (boldenone undecylenate). It is chemically a derivative of testosterone, characterized as a strong anabolic and low to moderately androgenic agent. As its name indicates, Boldione is simply the “dione” form of boldenone, activated in the body by the same widely distributed 17beta-hydroxysteroid dehydrogenase enzyme that converts androstenedione to testosterone. The chemical structures of both are:
Boldione (1,4-androstadiene-3,17-dione) Boldenone (1,4-androstadiene-3-one,17b-ol)
Boldione is truly the most advanced and potent anabolic prohormone ever developed, exhibiting several undeniable advantages over competing products:
The Most “Orally Active” Prohormone
Boldione is unquestionably the most orally active prohormone ever developed. As you probably know, poor oral bioavailability is one of the most fundamental problems with prohormones. The liver processes natural steroid hormones so efficiently, that when taken orally little will make its way all the way through to the blood stream in active from. All but a small percentage of the steroid will typically be found as an inactive 17-keto steroid. Here the 17 beta-hydroxyl group, vital to androgen binding, is removed and the compound rendered inactive. To solve this problem with pharmaceutical agents, chemists have synthetically altered most oral steroids with some form of 17-alpha alkylation (typically a methyl or ethyl addition), which virtually inhibits 17-ketosteroid reduction by occupying a carbon bond necessary for this reaction. But this type of alteration is also toxic to the liver, synthetic, and clearly not possible to use with natural prohormones.
The structure of Boldione however is intrinsically resistant to 17-ketosteroid deactivation during this first pass through the liver. The combination of its delta 1 and delta 4 double bond (1,4-Di Ene) shifts the hepatic metabolism (the 17-keto redox potential) of this compound far in favor of activation. This is made clear by studies showing Boldione to produce by far the most profound excretion of active 17beta-hydroxysteroids we have seen of any prohormone, as much as 50% of recovered urinary metabolites [1] . Surprisingly the 17beta-hydroxyl group survives hepatic metabolism to an enormous degree. Although this is not the near 100% recovery you would expect with a synthetic agent, it is amazingly superior (by far) to every other prohormone ever developed including the 1-androstene’s [2] .
…by far the most profound excretion of active 17beta-hydroxysteroids of any prohormone, as much as 50% of recovered urinary metabolites…
Figure 1 compares the 17-beta hydroxysteroid recovery of 4-androstenedione, the new 1-androstenedione, and Boldione (1,4-androstadienedione). As you can see, the delta 1 bond alone increases active metabolite recovery considerably. However when we add the additional delta 4 bond, the recovery is far more dramatic.
Figure 1. Average percentage of 17beta-hydroxysteroid metabolites recovered from human urine after 4-Androstenedione injection (J. Biol Chem 239(1964) 1578-84), 100mg oral 1-androstenedione (J Steroid Biochem 3 (1972) 933-6) and 100mg oral 1,4-androstadienedione (Steroids 18 (1971) 39-50).
Favorable Aromatization
Boldione converts to estrogen at roughly half the rate of androstenedione and testosterone [3] . This significantly reduces the level of estrogen buildup during use compared to that achieved with testosterone precursors, and similarly also lowers the chance of noticing strong estrogen related side effects such as increased body fat, gynecomastia and definition hiding water retention. It is no coincidence that the best bulking agents are estrogenic though, as this hormone does offer more than just side effects. Aside from the basic size increase we would attribute to fluid retention, estrogen also aids the muscle building process by enhancing glucose utilization for tissue growth and repair [4] [5] , increasing growth hormone secretion [6] and perhaps even by increasing androgen receptor concentrations [7] . It is clear today that estrogen serves a positive function in muscle growth, finally allowing us to explain a well known anecdotal fact: Aromatizable steroids are always the strongest muscle-builders, and preferred over non-aromatizable steroids when mass is desired. Boldione coverts to estrogen at a high enough rate to support excellent muscle gains, yet is typically mild enough to promote quality, defined growth without unwanted side effects. The long and fond relationship bodybuilders have had with boldenone is a clear testament to this fact.
… estrogen also aids the muscle building process by enhancing glucose utilization for tissue growth and repair, increasing growth hormone secretion and perhaps even by increasing androgen receptor concentrations…
Reduced Androgenic Activity
Boldenone is classified as an anabolic steroid, exhibiting much less androgenic activity than its analogue testosterone. This is because unlike testosterone, boldenone is a poor substrate for the 5-alpha reductase enzyme [8] . This is the enzyme responsible for converting testosterone to the more potent steroid dihydrotestosterone in many androgen responsive tissues such as the skin, scalp, prostate and central nervous system. Consequently the local potency of testosterone is increased significantly in these tissues, often allowing it to trigger unwanted side effects such as oily skin, acne, body/facial hair growth and male pattern hair loss (for those with a genetic predisposition). But boldenone tends to interact with the 5-beta reductase enzyme instead, which reduces this steroid into a very weak binder of the androgen receptor instead of potentiating its activity. Consequently boldenone is much milder in terms of androgenic side effects compared to testosterone, being much more similar to nandrolone in this regard.
A Naturally Occurring Hormone
In order for any prohormone to be classified as a nutritional supplement, the compound in question must be “naturally occurring”. This means that we must isolate a clear source for it in nature, without human synthesis. Thankfully 1,4-androstadienedione was shown unquestionably to be a natural androgen in cows. The first study to isolate this compound was conducted back in 1956, where scientists believed that it was most likely produced from progesterone in the animal’s gastrointestinal tract [9] . Later studies show the production of this hormone in cow ovarian tissues however [10] , suggesting another location and method of endogenous production. We can also look toward studies in the agricultural industry, where the natural occurrence of 1,4-dienones [11] have caused some difficulty and debate over the screening processes used for detecting the illegal use of boldenone in cattle. Many have suggested threshold limits to prevent false positives due to the low level of 1,4-diene androgens that may be present naturally in these animals.
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