DuoDeca contains:
150 mg/ml Nandrolone Decanoate
50 mg/ml Nandrolone Phenylpropionate

The following study had a big influence on some products as developed by Hard Core Labs (HCL).

Because of this study our advisor (RT) developed a stable compound that contains both esters used in this study: 150 mg/ml nandrolone decanoate and 50 mg/ml nandrolone phenylpropionate, because he assumed that it would work synergistic. The results amoung users proved him right.

Pharmacokinetics and Pharmacodynamics of Nandrolone Esters in Oil Vehicle: Effects of Ester, Injection Site and Injection Volume. Minto et all, JPET 281:93–102, 1997
Exerpt from the study that explains why the Organon Company conducted this study:

“The influence of site and volume of injection on the release kinetics of androgen esters from oil vehicle depots has, however, not been systematically investigated in humans.

This study compared the pharmacokinetics and pharmacodynamics of two currently available esters of nandrolone, the decanoate and phenylpropionate, as well as the influence of i.m. injection sites (gluteal vs. deltoid) and injection volumes (4 ml vs. 1 ml). In addition to measuring plasma nandrolone to investigate pharmacokinetics. “

Volume and Concentration

Steroids come in all shapes and sizes. In other words, you can find nandrolone (or Testosterone or boldenone) esters in 25 mg/ml, 50 mg/ml, 100 mg/ml, 200 mg/ml and so forth. Is a 400 mg injection using two milliliters of a 200 mg/ml oily solution the same as using four milliliters of a 100 mg/ml solution? After all, the net amount is still 400 mg, right? Unfortunately, this isn’t the case.

Steroid concentration in the solution greatly affects the dynamics and kinetics. In this study, some of the men received a 100 mg/ml injection of nandrolone decanoate and other men received a 100 mg injection using a 25 mg/ml solution (which means they received four milliliters, of course). Those that received the 100 mg/ml injection reached significantly higher (between 30% and 50%) plasma levels of nandrolone than those who got 100 mg via the 25 mg/ml solution. To top it off, the 100 mg/ml group’s plasma nandrolone level stayed elevated for a little bit longer; however, the length of suppression of endogenous Testosterone was almost identical.

What does this tell us? It tells us that if we want to maximize plasma levels of hormone (and thereby, maximize gains in lean muscle) we want to opt for the most concentrated version of whatever steroid(s) we decide we’re going to use. If we?re using Testosterone, we surely want to use a 200mg/ml enanthate over something like 100mg enanthate. If we’re using nandrolone, we want to use 200mg/ml stuff over 50mg/ml or 100mg/ml nandrolone decanoate made by others.


An other remarkeble result from this study was the fact that an injection in the butt cheek gave much better results then the same amount in the deltoid (shoulder).

For more information: common sense cycling

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