One will notice many prohormones have the suffix of either diol or dione. For example, there’s androstenedione and androstenediol. What does this mean?
Prohormones are precursor hormones. This means that once you eat androstenedione it will convert to testosterone in your liver. Because the diol and dione prohormone structures are different, the physical processes undergone to convert diols and diones to testosterone also are different. Specifically, separate enzymes convert diols and diones to the target hormone.
As mentioned above, prohormones are precursors to hormones. Chemically, they are very similar to the actual hormones. Diols have a keto group in the seventeeth position. Testosterone has a hydroxyl group in the seventheeth position. Otherwise, they are identical. Diones have a hydroxyl group in the 3rd position, while testosterone has a keto group in the third position. Otherwise, they too are identical.
The diol enzyme (3b-HSD) converts the one differing molecular group in the prohormone to turn the prohormone into testosterone. The dione enzyme (17b-HSD) converts the one different molecular group in the dione prohormone to make the prohormone into testosterone.
There are two caveats concerning the enzymatic conversion. First, the diol and dione enzymes do not operate at the same level of efficiency. Second, they are present in different concentrations.
The diol enzymes work to convert about 15% of the prohormone into testosterone. The dione enzymes work to convert about 5% of the prohormone into testosterone. This means that you’ll have to take about 3x the quantity of dione prohormones to equal the same effective dosage of diol prohormones. Assuming they’re the same price, it would make sense to use the diol prohormones over the dione prohormones because of less liver damage, right? Not quite so simple.
The fact of the matter is different people respond better to diols vs diones, and vice-versa. One theory that some people respond better to diones than diols is the “enzyme availability theory.” This states that there are more dione enzymes present in the body than the diol enzymes. So even though diols convert more efficiently into testosterone, the body can convert more dione than diol into testosterone.
