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- Mar 18, 2012
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There has been much debate on accurate half life calculations over the years, here is a more updated list:
The formula used for calculating the rate of compound release at a given day t is:
λ * N(t)
Where λ is the decay constant equal to ln(2)/h, h being the half life of the compound given in days; and N(t) is the half-life equation given by:
N(t) = n * e^(-t/λ)
Where n is the original dose of the compound in mg and t is given in days.
Terminal Half-lives
Testosterone Propionate: 0.8 days
Testosterone Phenylpropionate: 1.5 days
Testosterone Isocaproate: 4.0 days
Testosterone Enanthate: 4.5 days
Testosterone Cypionate: 5.0 days
Testosterone Decanoate: 7.5 days
Testosterone Undecanoate: 20.9 days
Trenbolone Acetate: 1.0 days
Trenbolone Enanthate: 4.5 days
Masteron Propionate: 0.8 days
Masteron Enanthate: 4.5 days
Nandrolone Phenylpropionate: 1.5 days
Nandrolone Decanoate: 7.5 days
Equipoise: 14.0 days
Primobolan Oral: 5 hours
Primobolan Injectable: 4.5 days
Halotestin: 7 hours
Anadrol: 14 hours
Dianabol: 5 hours
Turinabol: 16 hours
Winstrol Oral: 8 hours
Winstrol Injectable: 1.0 days
Anavar: 10 hours
Superdrol: 10 hours
These half-lives are approximations, and may vary slightly depending on injection site, carrier oil, and other factors.
Note: A different list of half-lives is often copy and pasted on various sites, claiming that, for example, the half-life for the propionate ester is 4.5 days and that the half-life for the enanthate ester is 10.5 days. This list is incorrect, and is the result of flawed calculations by Bill Roberts many years ago. See the "References" section for more information.
Active Dose
Injectable steroids are typically bound by esters, which comprise a portion of the steroid's weight. Because of this, 100mg of, for example, testosterone enanthate does not equate to 100mg of pure testosterone. In this case, there is only 70mg of testosterone being injected, and the remaining 30mg is the enanthate ester. This is taken into account when plotting cycles on this site, as different esters have different weights. Listed below is the percentages of the actual hormones for different steroid and ester combinations:
Testosterone Propionate: 80%
Testosterone Phenylpropionate: 66%
Testosterone Isocaproate: 72%
Testosterone Enanthate: 70%
Testosterone Cypionate: 69%
Testosterone Decanoate: 62%
Testosterone Undecanoate: 61%
Trenbolone Acetate: 87%
Trenbolone Enanthate: 70%
Masteron Propionate: 80%
Masteron Enanthate: 70%
Nandrolone Phenylpropionate: 67%
Nandrolone Decanoate: 64%
Equipoise: 61%
Primobolan Oral: 100%
Primobolan Injectable: 70%
Halotestin: 100%
Anadrol: 100%
Dianabol: 100%
Turinabol: 100%
Winstrol Oral: 100%
Winstrol Injectable: 87%
Anavar: 100%
Superdrol: 100%
References
Behre HM, Nieschlag E. 1998 Comparative pharmacokinetics of testosterone esters. In: Nieschlag E, Behre HM, eds. Testosterone: Action, Deficiency, Substitution, ed 2. Berlin: Springer-Verlag; 329–348.
The formula used for calculating the rate of compound release at a given day t is:
λ * N(t)
Where λ is the decay constant equal to ln(2)/h, h being the half life of the compound given in days; and N(t) is the half-life equation given by:
N(t) = n * e^(-t/λ)
Where n is the original dose of the compound in mg and t is given in days.
Terminal Half-lives
Testosterone Propionate: 0.8 days
Testosterone Phenylpropionate: 1.5 days
Testosterone Isocaproate: 4.0 days
Testosterone Enanthate: 4.5 days
Testosterone Cypionate: 5.0 days
Testosterone Decanoate: 7.5 days
Testosterone Undecanoate: 20.9 days
Trenbolone Acetate: 1.0 days
Trenbolone Enanthate: 4.5 days
Masteron Propionate: 0.8 days
Masteron Enanthate: 4.5 days
Nandrolone Phenylpropionate: 1.5 days
Nandrolone Decanoate: 7.5 days
Equipoise: 14.0 days
Primobolan Oral: 5 hours
Primobolan Injectable: 4.5 days
Halotestin: 7 hours
Anadrol: 14 hours
Dianabol: 5 hours
Turinabol: 16 hours
Winstrol Oral: 8 hours
Winstrol Injectable: 1.0 days
Anavar: 10 hours
Superdrol: 10 hours
These half-lives are approximations, and may vary slightly depending on injection site, carrier oil, and other factors.
Note: A different list of half-lives is often copy and pasted on various sites, claiming that, for example, the half-life for the propionate ester is 4.5 days and that the half-life for the enanthate ester is 10.5 days. This list is incorrect, and is the result of flawed calculations by Bill Roberts many years ago. See the "References" section for more information.
Active Dose
Injectable steroids are typically bound by esters, which comprise a portion of the steroid's weight. Because of this, 100mg of, for example, testosterone enanthate does not equate to 100mg of pure testosterone. In this case, there is only 70mg of testosterone being injected, and the remaining 30mg is the enanthate ester. This is taken into account when plotting cycles on this site, as different esters have different weights. Listed below is the percentages of the actual hormones for different steroid and ester combinations:
Testosterone Propionate: 80%
Testosterone Phenylpropionate: 66%
Testosterone Isocaproate: 72%
Testosterone Enanthate: 70%
Testosterone Cypionate: 69%
Testosterone Decanoate: 62%
Testosterone Undecanoate: 61%
Trenbolone Acetate: 87%
Trenbolone Enanthate: 70%
Masteron Propionate: 80%
Masteron Enanthate: 70%
Nandrolone Phenylpropionate: 67%
Nandrolone Decanoate: 64%
Equipoise: 61%
Primobolan Oral: 100%
Primobolan Injectable: 70%
Halotestin: 100%
Anadrol: 100%
Dianabol: 100%
Turinabol: 100%
Winstrol Oral: 100%
Winstrol Injectable: 87%
Anavar: 100%
Superdrol: 100%
References
Behre HM, Nieschlag E. 1998 Comparative pharmacokinetics of testosterone esters. In: Nieschlag E, Behre HM, eds. Testosterone: Action, Deficiency, Substitution, ed 2. Berlin: Springer-Verlag; 329–348.
I see he's now gone fully online though!