# Undecanoate VS. Enanthate



## miami797 (Feb 19, 2004)

Article 1:

*Injectable testosterone undecanoate has more favourable pharmacokinetics and pharmacodynamics than testosterone enanthate *CJ Partsch, GF Weinbauer, R Fang, and E Nieschlag

Institute of Reproductive Medicine of the University, Munster, Germany.

Testosterone preparations producing constant physiological testosterone serum levels are desirable for long-term treatment of androgen deficiency. However, all injectable testosterone esters used clinically for substitution of male hypogonadism are characterized by unfavourable pharmacokinetics. We therefore tested two groups of five long-term orchidectomized cynomolgus monkeys (Macaca fascicularis), which received a single intramuscular injection of 10 mg/kg body weight of an injectable testosterone undecanoate (TU) preparation or testosterone enanthate (TE) in a preclinical study to assess the pharmacokinetic and pharmacodynamic characteristics of TU in comparison to TE. The dose was equivalent to 6.3 and 7.2 mg of pure testosterone per kilogram body weight in the TU and TE group, respectively. Following injection of TU, mean serum testosterone rose to 58 +/- 18 nmol/l on day 1 and remained at moderately supraphysiological levels of 40-68 nmol/l for 45 days. Thereafter, testosterone levels were maintained in the normal range of intact monkeys for another 56 days. The TE injection resulted in highly supraphysiological levels of 100-177 nmol/l from immediately after the injection to day 5. A rapid decline followed and testosterone levels reached the lower limit of normal after 31 days. Serum testosterone levels were significantly higher in the TE-than in the TU-treated animals on days 0.5-7 (p < 0.05). Significantly lower testosterone levels were seen in the TE than in the TU group on days 16, 22, 25 and 31 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Article 2:

*Repeated intramuscular injections of testosterone undecanoate for substitution therapy in hypogonadal men*

Eberhard Nieschlag, Dorothee Büchter, Sigrid von Eckardstein, Katrin Abshagen, Manuela Simoni & Hermann M. Behre0Institute of Reproductive Medicine of the University, Münster, Germany

Correspondence to: Prof. Dr E. Nieschlag, Institute of Reproductive Medicine of the University, Domagkstr.11, D-48149 Münster, Germany. Fax: + 49 251835 6093; E-mail: [email protected]

OBJECTIVE

To investigate the suitability of intramuscular testosterone undecanoate (TU) injections for substitution therapy in hypogonadal men.

STUDY DESIGN

Clinical, open-label, non-randomized trial of 13 hypogonadal men receiving 4 intramuscular injections of 1000 mg TU in 4-ml castor oil at 6-week intervals. General wellbeing, sexual parameters, clinical chemistry, hormone levels, prostate size and prostate-specific antigen (PSA) were evaluated over 24 weeks and compared with baseline values.

RESULTS

Testosterone serum levels were never found below the lower limit of normal and only briefly after the 3rd and 4th injection above the upper limit of normal, while peak and trough values increased over the 24-week observation period. Oestradiol and dihydrotestosterone followed this pattern, not exceeding the normal limits. No serious side-effects were noted. Slight increases in body weight, haemoglobin, haematocrit, prostate volume and PSA, suppression of gonadotrophins as well as increased ejaculation frequency occurred as signs of adequate testosterone substitution.

CONCLUSION

Testosterone undecanoate is well tolerated by the patients. The injection intervals can be extended even beyond the 6-week periods chosen in the present study. Altogether, intramuscular testosterone undecanoate appears to be well suited for long-term substitution therapy in hypogonadism and hormonal male contraception

Links to these articles:

1. http://www.eje-online.org/cgi/content/abstract/132/4/514

2. http://www.blackwell-synergy.com/links/doi/10.1046/j.1365-2265.1999.00881.x


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## hackskii (Jul 27, 2003)

I saw swale answer to this one.

He suggested it was too hard to dose a man with a super long ester.

But then again he is a TRT doc.

This is one reason why I suggest guys wait 3 week after last shot of sust.

But looking at this maybe 4 weeks might be better for recovery.

But if you hate jabs then this is very cool and you could shoot every couple or even few weeks depending on dose.


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## Nytol (Jul 16, 2005)

You will have to up the dose though, as you get less test per gram, as the Undec ester is bigger that the enanthate ester.


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## hackskii (Jul 27, 2003)

Nytol said:


> You will have to up the dose though, as you get less test per gram, as the Undec ester is bigger that the enanthate ester.


It weights more due to the ester coorect?

So you get less mg per ml correct?

But not having to jab for awhile to me sounds great, but the clearance time to start PCT would be terribly hard to calculate.

Damn near would have to go on blood work


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## miami797 (Feb 19, 2004)

Ester weight. Same reason for the enanthare-cypionate debate (well, one of the reasons).

Although, it's such a small difference I doubt you would even know it.

Would've like to see the doc's response to this.


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## Nytol (Jul 16, 2005)

hackskii said:


> *It weights more due to the ester coorect?*
> 
> *
> So you get less mg per ml correct?*
> ...


Yes that is correct.


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## Nytol (Jul 16, 2005)

miami797 said:


> Ester weight. Same reason for the enanthare-cypionate debate (well, one of the reasons).
> 
> Although, it's such a small difference I doubt you would even know it.
> 
> Would've like to see the doc's response to this.


It is a much bigger difference than the enth/cyp compounds

Enth is about 30% ester weight, where as Undec is nearly 40%.

Over the course of a 10 week cycle, at 1g per week, that adds up to be a fair difference in the amount of test actually available to the body.

Certainly something to take into account.

Where as cyp/enth is only 1% difference in ester weight.


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## miami797 (Feb 19, 2004)

Molecular weight of these two. Not saying your're wrong Nytol, just adding to it with some numbers.

Testosterone Base: 288.4

Testosterone Enanthate: 400.6

Testosterone Undecanoate: 456.7

Testosterone Cypionate: 412.6

Also, undecanoate has 11 carbons and 22 hydrogens. I'm sure most of you already know that enanthate has C7 H14.


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## Nytol (Jul 16, 2005)

Milligrams below are the estimated amount of active hormone per 100mg of hormone and ester

Testosterone Base: 100mg

Testosterone Acetate: 83mg

Testosterone Propionate: 80mg

Testosterone Isocaproate: 72mg

Testosterone Enanthate: 70mg

Testosterone Cypionate: 69mg

Testosterone Phenylpropionate: 66mg

Testosterone Decanoate: 62mg

Testosterone Undecanoate: 61mg


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## hackskii (Jul 27, 2003)

Nytol said:


> Milligrams below are the estimated amount of active hormone per 100mg of hormone and ester
> 
> Testosterone Base: 100mg
> 
> ...


Ouch, so what would sust be in total mg for test then?

Under 200mg?


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## miami797 (Feb 19, 2004)

hackskii said:


> Ouch, so what would sust be in total mg for test then?
> 
> Under 200mg?


Sustanon250 (30mg prop, 60mg phenyl prop, 60mg iso, 100mg deca) would wind up coming out with about 169.2mg of actual test. If you go according to these numbers you come out with this

prop @ 24mg

phen @ 40mg

iso @ 43.2

deca @ 62mg

correct me if I'm wrong, but this is what I'm coming up with.


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## hackskii (Jul 27, 2003)

My math sucks, I would not even guess but I bet that is pretty freaking close.


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## Nytol (Jul 16, 2005)

Yeah that is about right, make you think a bit more about what drug ester to use, e.g phenylprop is ****, as it is pretty much the same as prop but a lot bigger, so less test.

Unfortunately we have to put up with it in NPP, as there is no Nandrolone Prop, but there is Nandrolone base, and I shall be aquiring some soon,


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## tkd (Feb 27, 2006)

The leaflet inside my testoviron depot says :

1ml / 250mg testosterone enanthate contains the equivalent of 180mg of testosterone.


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## Nytol (Jul 16, 2005)

That is about right then, 175/180mg


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## miami797 (Feb 19, 2004)

250mg should have about 175mg.

I would bet that schering doesn't under dose either. Some labs even over dose the products too. I've seen lab reports from two seperate lots of jelfa that were overdosed by almost 50mg, and this was on a 100mg test.

Maybe they do this to compensate for the esters. I can't see any other reason.


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