"Deca" Half-Life

[OhNoYo]

I was always under the impression that Deca-Durabolin (Nandrolone Decanoate) was approximately two weeks. However, this study says it is six days: Pharmacokinetic parameters of... [Acta Endocrinol Suppl (Copenh). 1985] - PubMed - NCBI

I provided the abstract below. So, what do you all think? Does anyone have any reputable literature to validate or refute this?

AbstractNandrolone decanoate (Deca-Durabolin) was injected intramuscularly into healthy volunteers. One group of females received one injection of 100 mg and three groups of males received one injection of 200 mg, two repeat injections of 100 mg or four repeat injections of 50 mg respectively. The serum levels of nandrolone (19-nortestosterone) were determined by radioimmunoassay and used to estimate pharmacokinetic parameters. The following pharmacokinetic parameters were found: a mean half-life of 6 days for the release of the ester from the muscular injection depot into the general circulation; a mean half-life of 4.3 h for the combined processes of hydrolysis of nandrolone decanoate and of distribution and elimination of nandrolone; a mean nandrolone serum clearance of 1.55 1 X h-1 X kg-1. The half-life of hydrolysis of nandrolone decanoate in serum was of the order of one hour or less. The data are consistent with linear kinetics.

 

[CensoredBoardsSuck]

I was always under the impression that Deca-Durabolin (Nandrolone Decanoate) was approximately two weeks. However, this study says it is six days: Pharmacokinetic parameters of... [Acta Endocrinol Suppl (Copenh). 1985] - PubMed - NCBI

I provided the abstract below. So, what do you all think? Does anyone have any reputable literature to validate or refute this?

J Clin Endocrinol Metab. 2005 May;90(5):2624-30. Epub 2005 Feb 15.
Pharmacokinetic evaluation of three different intramuscular doses of nandrolone decanoate: analysis of serum and urine samples in healthy men. Pharmacokinetic evaluation of three ... [J Clin Endocrinol Metab. 2005] - PubMed - NCBI
Bagchus WM1, Smeets JM, Verheul HA, De Jager-Van Der Veen SM, Port A, Geurts TB.

Abstract

The pharmacokinetics of nandrolone in serum and urine were investigated in healthy young men after a single im injection of 50 mg (n = 20), 100 mg (n = 17), or 150 mg (n = 17) nandrolone decanoate. Blood samples were collected before treatment and for up to 32 d after dosing. In addition, in the 50- and 150-mg groups, 24-h urine samples were collected before treatment and on d 1, 7, and 33 after treatment; in the 150-mg group, additional samples were collected after 3 and 6 months. Serum concentrations and the area under the curve of nandrolone increased proportionally with the dose administered. The peak serum concentration ranged from 2.14 ng/ml in the 50-mg group to 4.26 ng/ml in the 100-mg group and 5.16 ng/ml in the 150-mg group. The peak serum concentration was reached after 30 h (50 and 100 mg) and 72 h (150 mg), whereas the terminal half-life was 7-12 d. In urine, pretreatment concentrations of 19-norandrosterone (19-NA) and/or 19-noretiocholanolone (19-NE) were detected in five of 37 subjects (14%). In the 50-mg group, 19-NA and/or 19-NE could be detected at least until 33 d after injection in 16 of 17 subjects (94%). In the 150-mg group, who were presumed to have not previously used nandrolone, nandrolone metabolites could be detected for up to 6 months in eight of 12 subjects (67%) for 19-NE and in 10 of 12 subjects (83%) for 19-NA.

 

[OhNoYo]

J Clin Endocrinol Metab. 2005 May;90(5):2624-30. Epub 2005 Feb 15.
Pharmacokinetic evaluation of three different intramuscular doses of nandrolone decanoate: analysis of serum and urine samples in healthy men. Pharmacokinetic evaluation of three ... [J Clin Endocrinol Metab. 2005] - PubMed - NCBI
Bagchus WM1, Smeets JM, Verheul HA, De Jager-Van Der Veen SM, Port A, Geurts TB.

Abstract

The pharmacokinetics of nandrolone in serum and urine were investigated in healthy young men after a single im injection of 50 mg (n = 20), 100 mg (n = 17), or 150 mg (n = 17) nandrolone decanoate. Blood samples were collected before treatment and for up to 32 d after dosing. In addition, in the 50- and 150-mg groups, 24-h urine samples were collected before treatment and on d 1, 7, and 33 after treatment; in the 150-mg group, additional samples were collected after 3 and 6 months. Serum concentrations and the area under the curve of nandrolone increased proportionally with the dose administered. The peak serum concentration ranged from 2.14 ng/ml in the 50-mg group to 4.26 ng/ml in the 100-mg group and 5.16 ng/ml in the 150-mg group. The peak serum concentration was reached after 30 h (50 and 100 mg) and 72 h (150 mg), whereas the terminal half-life was 7-12 d. In urine, pretreatment concentrations of 19-norandrosterone (19-NA) and/or 19-noretiocholanolone (19-NE) were detected in five of 37 subjects (14%). In the 50-mg group, 19-NA and/or 19-NE could be detected at least until 33 d after injection in 16 of 17 subjects (94%). In the 150-mg group, who were presumed to have not previously used nandrolone, nandrolone metabolites could be detected for up to 6 months in eight of 12 subjects (67%) for 19-NE and in 10 of 12 subjects (83%) for 19-NA.

Ah, nice find, Lad.

The scientists though go into more detail about half-lives though, speaking more than just "terminal", as absorption & elimination half-lives are both approximately 5-6 days. Terminal half-life though is ~7d for 50mg IM, while ~12d for 100mg or 150mg.

I would like all you Lads to take a look at Table 2 & lemme know whatcha think as well as anymore pertinent info about estimated half-life of "Deca", as it appears confusing/conflicting from research present: http://press.endocrine.org/doi/pdf/10.1210/jc.2004-1526

 

[Purge]

If I understand it correctly, the first post says it takes about 6 days for the nandrolone to move from the muscle to the bloodstream. Then it takes 7 - 12 days to fall from peak serum levels to one half that level (the definition of terminal half-life). Wouldn't that give 13 - 18 days for injection to one half serum level? That's about two weeks.

 

[Oregongearhead]

If you think deca's half-life is around a week or two you havent taken real deca at high doses. It last forever it seems . By far the longest of the androgens. Its been over a month since I had to abruptly stop my last deca cycle and the deca is just now clearing out . You"ve got to watch those "studys" , its easy to misinterpret what they are saying .

And remember alot those studies arent taking the kinds of doses that are took around here . We should be the ones being studied . 100-250mg took in the studies doesnt compare to a 500-750 mg deca cycle. So double the clearance time of whatever you read on Pub-Med .

 

[OhNoYo]

If you think deca's half-life is around a week or two you havent taken real deca at high doses. It last forever it seems . By far the longest of the androgens. Its been over a month since I had to abruptly stop my last deca cycle and the deca is just now clearing out . You"ve got to watch those "studys" , its easy to misinterpret what they are saying .

And remember alot those studies arent taking the kinds of doses that are took around here . We should be the ones being studied . 100-250mg took in the studies doesnt compare to a 500-750 mg deca cycle. So double the clearance time of whatever you read on Pub-Med .

Ah, nice catch there, Lad. Indeed, it does appear from some of the data posted that there is a dose-response increase from how much you take to how long its half-life, so associated clearance will be, at least in some of the half-life markers tested.

 

[OhNoYo]

If I understand it correctly, the first post says it takes about 6 days for the nandrolone to move from the muscle to the bloodstream. Then it takes 7 - 12 days to fall from peak serum levels to one half that level (the definition of terminal half-life). Wouldn't that give 13 - 18 days for injection to one half serum level? That's about two weeks.

They explain the parameters in more detail in the paper. If you cannot retrieve the from the website link I provided, I can provide by attaching it to a post, if you'd like to take a look at it.