6-OXO was the 1st effective anti-aromatase to hit the OTC market. Originally formulated and marketed by Patrick Arnold, the chemist-guru who brought pro-hormones to the marketplace, including the original 4AD and 1AD, Patrick was the man who helped launch the modern OTC prohormone movement. Patrick has also been responsible for bringing several undetectable designer steroids to elite athletes, has been featured in bodybuilding magazines as a monthly columnist, owns his own supplement company, and is still widely respected as an authority on anabolic chemistry and ergogenic aids. With that said, we will delve into 6-OXO and explain why it is still relevant today.

So, what are aromatase inhibitors? In Short, they are a category of compounds which reduce estrogen in the body, but in order to have a more thorough understanding of how aromatase inhibitors (which will be referred to as A.I’s from this point forward) work, we will need to define some of the other basic terms associated with the subject of aromatase inhibition. First of all, aromatase is an endogenously produced enzyme responsible for the conversion of testosterone into estrogen. Without aromatase, normal physiological functioning is impaired, as estrogen plays a critical role in the lives of males. However, excess aromatase can result in numerous negative side effects, some of which include increased bodyfat gain, female fat pattern distribution, increased blood pressure, water retention, gynecomastia, reduced libido and sexual functioning, as well as the suppression of both natural testosterone production and spermatogenesis.

While it is possible that elevated levels of estrogen may occur naturally, steroid users are often at a greater risk for experiencing these side effects, due to the use of aromatizable drugs, such as testosterone, Dianabol, etc. When administering a drug such as testosterone in supraphysiological quantities, the body’s natural hormonal environment is disturbed, altering the testosterone to estrogen ratio. In an attempt to correct this imbalance and restore equilibrium, the body’s natural response is to aromatize a portion of the available testosterone into estrogen; the more testosterone that is present, the more interaction will take place between testosterone and the aromatase enzyme.

This reaction may help to correct the T: E ratio, but it will not do anything to protect the body from the effects of excess estrogen levels. If this weren’t bad enough, users of aromatizable drugs often have to contend with the effects of elevated estrogen post-cycle, resulting in a prolonged recovery of the HPTA. Therefore, management of estrogen both during and post-cycle is critical if the individual wishes to avoid estrogenic side effects and restore testosterone production as quickly as possible.


In addition to the avoidance of estrogen-related side effects, 6-OXO may impart cosmetic benefits, such as an increase in the hardness & dryness of the musculature. This is primarily due to an overall decrease in the body’s level of estrogen–induced water retention and/or a more favorable ratio of androgens to estrogen, allowing the individual to showcase a more visually pleasing physique. 6-OXO also serves as an SHBG modulator, contributing to a further increase in free testosterone. While SHBG (sex hormone binding globulin) is a necessary hormone, it is also directly responsible for making most of the testosterone we produce/administer unavailable for use by the body. It accomplishes this by irreversibly binding to testosterone in the bloodstream, rendering it completely inactive and worthless for muscle-buildin, or anything else for that matter. In fact, about 98% of all circulating testosterone is bound by this seemingly adversarial protein. Needless to say, a reduction of SHBG is advantageous for those trying to add lean muscle tissue and 6-OXO helps to achieve this.



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Note; dosage information is only for scientific reference purposes. SARMs Central, does not condone the human consumption or use of this substance outside of a controlled scientific environment (i.e. a lab).

The recommended starting dose for 6-OXO-4-Androstene-3,6,17-Trione is 300mg daily and can be increased to a maximum of 600mg daily over an 8-week cycle period.

Potential Side Effects

  • Low estrogen levels – can lead to serious side effects in men (e.g. fatigue, joint pain, memory lapses, rise in cholesterol levels, night sweats and decreased libido)

  • Hair Loss – increased DHT can lead to alopecia

  • Risk of BPH (benign prostatic hyperplasia) – excess DHT can bind to the prostate causing it to swell

  • Acne – an increase in testosterone, DHT or changing hormonal levels can lead to acne (especially in the shoulders and back)

  • Does not totally impede estrogen

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