Esters Active Half-Life Table
Posted: Tue Nov 29, 2022 2:55 am
Esters Active Half-Life Table
Different esters exist for various compounds. Different esters give compounds different clearance times in the blood. All over the internet, you will find different (unreferenced) information on the half-life of compounds. A lot of the confusion comes from a lack of understanding on a compound's half-life versus it's biological or terminal half-life. For our purposes, we really only care about the terminal half-life, defined as:
The biological half-life or elimination half-life of a substance is the time it takes for a substance (for example a metabolite, drug, signaling molecule, radioactive nuclide, or other substance) to lose half of its pharmacologic, physiologic, or radiologic activity, as per the MeSH definition.
More information on terminal half-life is available here.
Reference study.
Ester Half-life Terminal Half-life
Suspension within 1 hour
Acetate 3 days 1 day
Propionate 2 days 0.8 days
Phenylpropionate 4.5 days 1.5 days
Butyrate 2-3 days
Valerate 3 days
Hexanoate 3 days
Caproate 4-5 days
Isocaproate 9 days 4 days
Heptanoate 5-6 days
Enanthate 10.5 days 4.5 days
Cypionate 6-7 days 5 days
Octanoate 6-7 days
Nonanoate 7 days
Decanoate 15 days 7.5 days
Undecylenate 8-9 days 14 days
Undecanoate 16.5 days 20.9 days
IMPORTANT NOTE: These half-lives are approximations, and may vary slightly depending on injection site, carrier oil, and other factors. There isn't any pharmacokinetics studies done on the majority of AAS. Most of the above is the theoretical half-lives when we are not presented with real data.
Esters And The Active Dose
It is important for every person to understand that the ester which is attached to any injectable anabolic steroid possesses a certain percentage amount of the total molecular weight of the molecule. Therefore, for example, 100mg of Testosterone Enanthate is not 100mg of pure Testosterone. The reality is that you are receiving less Testosterone than most of you think, and once the ester has been removed through the esterase enzyme, the amount of pure un-esterified Testosterone left over is very different depending on the ester in question that was previously attached to the hormone.
Long chain esters, such as Cypionate, Decanoate, Enanthate, etc. possess a much heavier molecular weight than short chain esters. Consequently, on a mg for mg basis, you are receiving far extra mg of steroid in a short estered compound as opposed to a large estered compound. As an example, there exists a larger amount of mg of Testosterone in 100mg of Testosterone Propionate than 100mg of Testosterone Enanthate. This is due to the shorter, and therefore lighter weight of the Propionate ester in comparison to the larger and therefore much heavier Enanthate ester. Many individuals just do not realize this, and should always consider this factor as one of the factors involved in the decision making process concerning which ester variant of any given compound to use during a cycle.
Listed below is the percentages of the actual hormones for each ester:
Ester % Of The Actual Hormone
Acetate 87%
Propionate 80%
Phenylpropionate 66-67%
Isocaproate 72%
Enanthate 70%
Cypionate 69%
Decanoate 62%
Undecylenate 61%
Undecanoate 61%
Different esters exist for various compounds. Different esters give compounds different clearance times in the blood. All over the internet, you will find different (unreferenced) information on the half-life of compounds. A lot of the confusion comes from a lack of understanding on a compound's half-life versus it's biological or terminal half-life. For our purposes, we really only care about the terminal half-life, defined as:
The biological half-life or elimination half-life of a substance is the time it takes for a substance (for example a metabolite, drug, signaling molecule, radioactive nuclide, or other substance) to lose half of its pharmacologic, physiologic, or radiologic activity, as per the MeSH definition.
More information on terminal half-life is available here.
Reference study.
Ester Half-life Terminal Half-life
Suspension within 1 hour
Acetate 3 days 1 day
Propionate 2 days 0.8 days
Phenylpropionate 4.5 days 1.5 days
Butyrate 2-3 days
Valerate 3 days
Hexanoate 3 days
Caproate 4-5 days
Isocaproate 9 days 4 days
Heptanoate 5-6 days
Enanthate 10.5 days 4.5 days
Cypionate 6-7 days 5 days
Octanoate 6-7 days
Nonanoate 7 days
Decanoate 15 days 7.5 days
Undecylenate 8-9 days 14 days
Undecanoate 16.5 days 20.9 days
IMPORTANT NOTE: These half-lives are approximations, and may vary slightly depending on injection site, carrier oil, and other factors. There isn't any pharmacokinetics studies done on the majority of AAS. Most of the above is the theoretical half-lives when we are not presented with real data.
Esters And The Active Dose
It is important for every person to understand that the ester which is attached to any injectable anabolic steroid possesses a certain percentage amount of the total molecular weight of the molecule. Therefore, for example, 100mg of Testosterone Enanthate is not 100mg of pure Testosterone. The reality is that you are receiving less Testosterone than most of you think, and once the ester has been removed through the esterase enzyme, the amount of pure un-esterified Testosterone left over is very different depending on the ester in question that was previously attached to the hormone.
Long chain esters, such as Cypionate, Decanoate, Enanthate, etc. possess a much heavier molecular weight than short chain esters. Consequently, on a mg for mg basis, you are receiving far extra mg of steroid in a short estered compound as opposed to a large estered compound. As an example, there exists a larger amount of mg of Testosterone in 100mg of Testosterone Propionate than 100mg of Testosterone Enanthate. This is due to the shorter, and therefore lighter weight of the Propionate ester in comparison to the larger and therefore much heavier Enanthate ester. Many individuals just do not realize this, and should always consider this factor as one of the factors involved in the decision making process concerning which ester variant of any given compound to use during a cycle.
Listed below is the percentages of the actual hormones for each ester:
Ester % Of The Actual Hormone
Acetate 87%
Propionate 80%
Phenylpropionate 66-67%
Isocaproate 72%
Enanthate 70%
Cypionate 69%
Decanoate 62%
Undecylenate 61%
Undecanoate 61%