Steroid Esters Part I

An extremely important, yet often forgotten, component of steroid chemistry is the fact that every esterified steroid (steroid with an ester attached) has a certain component of the steroids overall mass consisting of the weight of the ester, not of the hormone. This means that, 100mg of Testosterone Enanthate is not 100mg of pure Testosterone. In fact, you may have been severely under-dosing compared to what you though you were taking, and once the ester has been removed through the esterase enzyme, the amount of pure hormone testosterone left over is very different than what you thought you were administering. 


Long chain esters, such as Cypionate, Decanoate, Enanthate, etc. possess a significantly greater molecular weight than short chain esters. Consequently, on a mg per mg basis, you are receiving far more unesterified steroid in a short estered compound compared to a large estered compound. 100mg of Testosterone Propionate is not equivalent to 100mg of Testosterone Enanthate, contrary to common belief. This is due to the shorter, and consequently lighter weight of the propionate ester relative to the larger and heavier enanthate ester. Mindful bodybuilders should always consider this factor as one of the various elements that determine their choice of AAS type or dosage. Esters are an essential component of how steroid hormones are metabolized and should be common knowledge for anyone taking AAS.


In order to more appropriately convey the massive differences in the quantity of raw hormone in a given dosage depending on ester, here is a list of some of the most common esterified injectable compounds and how much free hormone is left in a given amount of the compound (standardized to 100mg),


100mg Testosterone Suspension (un-esterified Testosterone) = 100mg Testosterone

100mg Testosterone Acetate = 83mg Testosterone

100mg Testosterone Propionate = 80mg Testosterone

100mg Testosterone Isocaproate = 72mg Testosterone

100mg Testosterone Enanthate = 70mg Testosterone

100mg Testosterone Cypionate = 69mg Testosterone

100mg Testosterone Phenylpropionate = 66mg Testosterone

100mg Testosterone Decanoate = 62mg Testosterone

100mg Testosterone Undecanoate = 61mg Testosterone


100mg Trenbolone Acetate = 87mg Trenbolone

100mg Trenbolone Enanthate = 70mg Trenbolone 

100mg Trenbolone Hexahydrobenzylcarbonate = 70mg Trenbolone


100mg Nandrolone Phenylpropionate = 67mg Nandrolone

100mg Nandrolone Decanoate = 64mg Nandrolone


100mg Drostanolone Propionate = 80mg Drostanolone

100mg Drostanolone Enanthate = 70mg Drostanolone


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