Please Scroll Down to See Forums Below
.jpg "Research Chemical Sciences")
.png "Research Chemical Sciences")
padycakes_16
New member
bump
what do you guys think?
what do you guys think?
strong island
New member
I was doing a lot of research on this very topic. No consensus. Pharmacokinetics is a very technical science and there haven't been a lot of studies for the benefit of juiceheads.
Basically what I found is that undecylenate's half-life is supposedly compareable to undecanoate. I read an article on the anabolic extreme website that stated undecanoate should have a half life around 16.5 days. So undecylenate is "supposedly around that area"
But that article also said that enanthate has a half life of 10.5 days. But I have read in other articles that the half life is between 7-9.
Like I said..no consensus.
Basically what I found is that undecylenate's half-life is supposedly compareable to undecanoate. I read an article on the anabolic extreme website that stated undecanoate should have a half life around 16.5 days. So undecylenate is "supposedly around that area"
But that article also said that enanthate has a half life of 10.5 days. But I have read in other articles that the half life is between 7-9.
Like I said..no consensus.
1: Acta Endocrinol Suppl (Copenh) 1985;271:19-30 Related Articles, Books
1. Pharmacokinetic parameters of nandrolone (19-nortestosterone) after intramuscular administration of nandrolone decanoate (Deca-Durabolin) to healthy volunteers.
Wijnand HP, Bosch AM, Donker CW.
Nandrolone 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.
PMID: 3865478 [PubMed - indexed for MEDLINE]
--------------------------------------------------
1: Int J Androl 1984 Jun;7(3):181-7 Related Articles, Books
Comparative pharmacokinetics of testosterone enanthate and testosterone cyclohexanecarboxylate as assessed by serum and salivary testosterone levels in normal men.
Schurmeyer T, Nieschlag E.
The pharmacokinetics of 2 testosterone esters, testosterone enanthate and testosterone cyclohexanecarboxylate, were compared in a single blind crossover study in healthy young men. Their effects on serum and salivary levels of testosterone, as well as on the serum levels of LH, FSH and prolactin were measured after the injection of doses equivalent to 140 mg free testosterone. Both preparations yielded supraphysiological testosterone levels in serum and saliva as early as 2 h following injection, reaching peak levels 4 to 5 times above basal between 8 and 24 h. LH and FSH levels were suppressed as long as serum testosterone levels were elevated. Nine days after injecting testosterone enanthate and 7 days after giving testosterone cyclohexanecarboxylate, serum and salivary levels of testosterone had returned to basal. The longer activity of testosterone enanthate was also evidenced from more extended suppression of gonadotrophin levels. Although neither preparation is ideal because of the initial supraphysiological peaks, testosterone enanthate appears preferable for clinical use because of its slightly longer duration of action.
---------------
Nine days after injection of Enanthate serum level returned to normal, which gives us 4.5 days of half life.
-----------------------------------------------------------------------------
Pharmacokinetic properties of testosterone propionate in normal men
1. M Fujioka, Y Shinohara, S Baba, M Irie and K Inoue
The pharmacokinetic characteristics of testosterone propionate were studied in normal men after a single im dose of 25 mg testosterone propionate-19,19,19-d3. Plasma levels of testosterone propionate- 19,19,19-d3, its active metabolite testosterone-19,19,19-d3, and endogenous testosterone were measured by gas chromatography-mass spectrometry. Testosterone propionate-19,19,19-d3 was gradually transferred from the im injection site to the systemic circulation. The plasma levels of testosterone propionate-19,19,19-d3 were maintained at 2-4 ng/ml between 3 and 36 h after administration. Plasma testosterone- 19,19,19-d3 levels were maintained above the physiological testosterone level for 48 h, while plasma levels of endogenous testosterone changed little
------------------------------------------------------------------------------------
Bioavailability and LH-suppressing effect of different testosterone preparations in normal and hypogonadal men.
Nieschlag E, Cuppers HJ, Wiegelmann W, Wickings EJ.
The therapeutic effectiveness of intramuscularly administered testosterone esters and free testosterone in suppositories was investigated by the measurement of plasma testosterone and LH levels after administration to normal and hypogonadal men. Testosterone levels were elevated above the lower physiological limit for 1 day after 25 mg testosterone one propionate, for 2 days after 50 mg testosterone propionate and for 14 days after 250 mg testosterone oenanthate. LH levels were suppressed for the corresponding periods. Elevated plasma testosterone and suppressed LH levels were maintained by testosterone suppositories (3 x 20 mg for 5 days).
PMID: 1002121 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------------
What is summery of those studies, not articles, but studies?
Propionate's half life is 1-2 days, Enanthate's 5 days, Decanoate's 6 days.
Now, isn't it obvious that with carbon chain just slightly longer then Decanoate, Undecylanate's half life can't possibly be nothing even close to 16 days?
I don't think, anyone will find studies done on that particular ester, but, I 8-9 days of half life sound the most logical.
1. Pharmacokinetic parameters of nandrolone (19-nortestosterone) after intramuscular administration of nandrolone decanoate (Deca-Durabolin) to healthy volunteers.
Wijnand HP, Bosch AM, Donker CW.
Nandrolone 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.
PMID: 3865478 [PubMed - indexed for MEDLINE]
--------------------------------------------------
1: Int J Androl 1984 Jun;7(3):181-7 Related Articles, Books
Comparative pharmacokinetics of testosterone enanthate and testosterone cyclohexanecarboxylate as assessed by serum and salivary testosterone levels in normal men.
Schurmeyer T, Nieschlag E.
The pharmacokinetics of 2 testosterone esters, testosterone enanthate and testosterone cyclohexanecarboxylate, were compared in a single blind crossover study in healthy young men. Their effects on serum and salivary levels of testosterone, as well as on the serum levels of LH, FSH and prolactin were measured after the injection of doses equivalent to 140 mg free testosterone. Both preparations yielded supraphysiological testosterone levels in serum and saliva as early as 2 h following injection, reaching peak levels 4 to 5 times above basal between 8 and 24 h. LH and FSH levels were suppressed as long as serum testosterone levels were elevated. Nine days after injecting testosterone enanthate and 7 days after giving testosterone cyclohexanecarboxylate, serum and salivary levels of testosterone had returned to basal. The longer activity of testosterone enanthate was also evidenced from more extended suppression of gonadotrophin levels. Although neither preparation is ideal because of the initial supraphysiological peaks, testosterone enanthate appears preferable for clinical use because of its slightly longer duration of action.
---------------
Nine days after injection of Enanthate serum level returned to normal, which gives us 4.5 days of half life.
-----------------------------------------------------------------------------
Pharmacokinetic properties of testosterone propionate in normal men
1. M Fujioka, Y Shinohara, S Baba, M Irie and K Inoue
The pharmacokinetic characteristics of testosterone propionate were studied in normal men after a single im dose of 25 mg testosterone propionate-19,19,19-d3. Plasma levels of testosterone propionate- 19,19,19-d3, its active metabolite testosterone-19,19,19-d3, and endogenous testosterone were measured by gas chromatography-mass spectrometry. Testosterone propionate-19,19,19-d3 was gradually transferred from the im injection site to the systemic circulation. The plasma levels of testosterone propionate-19,19,19-d3 were maintained at 2-4 ng/ml between 3 and 36 h after administration. Plasma testosterone- 19,19,19-d3 levels were maintained above the physiological testosterone level for 48 h, while plasma levels of endogenous testosterone changed little
------------------------------------------------------------------------------------
Bioavailability and LH-suppressing effect of different testosterone preparations in normal and hypogonadal men.
Nieschlag E, Cuppers HJ, Wiegelmann W, Wickings EJ.
The therapeutic effectiveness of intramuscularly administered testosterone esters and free testosterone in suppositories was investigated by the measurement of plasma testosterone and LH levels after administration to normal and hypogonadal men. Testosterone levels were elevated above the lower physiological limit for 1 day after 25 mg testosterone one propionate, for 2 days after 50 mg testosterone propionate and for 14 days after 250 mg testosterone oenanthate. LH levels were suppressed for the corresponding periods. Elevated plasma testosterone and suppressed LH levels were maintained by testosterone suppositories (3 x 20 mg for 5 days).
PMID: 1002121 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------------
What is summery of those studies, not articles, but studies?
Propionate's half life is 1-2 days, Enanthate's 5 days, Decanoate's 6 days.
Now, isn't it obvious that with carbon chain just slightly longer then Decanoate, Undecylanate's half life can't possibly be nothing even close to 16 days?
I don't think, anyone will find studies done on that particular ester, but, I 8-9 days of half life sound the most logical.
Last edited:
Another very interesting study, not connected directly to the topic of this thread, but explaining a lot about half lives of steroids, etc..
Very good read:
http://jpet.aspetjournals.org/cgi/content/full/281/1/93#F2
Very good read:
http://jpet.aspetjournals.org/cgi/content/full/281/1/93#F2
strong island
New member
Great info...but still shady.
The enanthate study only used the equivalent of 140mg of Test. Then it reports levels reached 4-5 times basal levels. That means basal test levels must have been around 35.(I do no know much about basal levels but that sounds pretty low.)
I would love to see studies with 500 grams of test shot per week for a few weeks. Maybe a large depot slows the distribution, maybe when blood levels are higher the liver can't metabolize the steroids as fast. Especially with multiple doses.
I would love to know where that guy from anabolic extreme got his info.
Great stuff panerai...I have been getting very interested in this shit lately, could you recommend any good books.
The enanthate study only used the equivalent of 140mg of Test. Then it reports levels reached 4-5 times basal levels. That means basal test levels must have been around 35.(I do no know much about basal levels but that sounds pretty low.)
I would love to see studies with 500 grams of test shot per week for a few weeks. Maybe a large depot slows the distribution, maybe when blood levels are higher the liver can't metabolize the steroids as fast. Especially with multiple doses.
I would love to know where that guy from anabolic extreme got his info.
Great stuff panerai...I have been getting very interested in this shit lately, could you recommend any good books.
Similar threads
