6-O'XO also known as 4-androsten-3,6,17-trione3,6,17-androstenetrione androst-4-ene-3,6,17-trione 6-ketoandros'tenedione is a stero aromatase inhibitor, known as a suicidal inhibitor because it permanently binds to the aromatase enzyme.Its primary use is for Estrogen blocking and inhibtion. It also elevates levels of test.

Ingredients such as 6-O'XO are becoming increasingly hard to find and purchase becuase of its strength.Its also worth mentioning that 6-o'xo should never be used post cycle, as its steroidial effects would likely interfere with recovery of natural test production.

An eight week study was done at Baylor University to determine the effects of 300 mg or 600mg of 6-o'xo used by resistance trained males. The study showed an increse of 90% for 300 mg group and 84% for the 600 mg group. The study concluded that the ratio of free test to estradiol increased significatly.

The 6-O'XO (4-A'ndrostene-3,6,17-trione) disables the Aromatase enzyme. The chemical reaction is classified as a "suicide inhibition". What this really means is that one molecule of 4-A'ndrostene-3,6,17-trione binds to one molecule of Aromatase permanently. The Aromatase molecule is not destroyed or broken into pieces, but it is neutralized by the 4-A'ndrostene-3,6,17-trione. While these molecules are bonded together, Aromatase cannot interact with test and convert it to estrogen, and is eventually degraded by other enzymes or eliminated through urine.