Understanding Esters, Active-Life and Half-Life

[GetXXL]

Been a long time since I did maths at school mate, 41 this year. Just to think I actually went to college to do A level pure and applied maths with the hope of doing maths at uni. Anyway, dropped out!

However, in our example, where the ester has 2 days half life. If I inject 500mg every day for 10 days, will I yield the same result as injecting 1000mg every other day for the same 10 day period? Does maths do the magic again???

This is what forums are for.....Thanks for joining in the convo GetXXL

Yes, after the 10 days they will have exactly the same wash-out period. Do note that 1000mg EOD yields less stable bloodlevels than 500mg ED does, but if you avarage them out they will yield the same "result" yes. Maths do the magic again

I'm a computer science student at uni, so I'm expected to know my maths :p Although I'm not very good at it hehe.

Furthermore you can use the first derivate of this function to calculate the slope of a specific point (derivate of 1/(2^n) = -2^(-n)log(2)) and use the primitive to integrate under the graph (the integral is (-(2^-n)/log(2))) I think, not sure) whereas n is the amount of half-lifes past.

 

[B|GJOE]

Yes, after the 10 days they will have exactly the same wash-out period. Do note that 1000mg EOD yields less stable bloodlevels than 500mg ED does, but if you avarage them out they will yield the same "result" yes. Maths do the magic again

I'm a computer science student at uni, so I'm expected to know my maths :p Although I'm not very good at it hehe.

Furthermore you can use the first derivate of this function to calculate the slope of a specific point (derivate of 1/(2^n) = -2^(-x)log(2)) and use the primitive to integrate under the graph (the integral is -(log(2) / 2^x) I think, not sure).

I do like maths. Used to do PHP and MySQL web based apps, and at work I've created quite a lot of Excel VBA applications. But saying that, it's the old gigo isn't it. You have know the formula to get the desired result. Been a great thread, and I've achieved the objective of understanding half life from it.

However, I still don't get why the internet has contradictory info on the actual half life of the different esters, I mean min 4 days and max 12 days quoted for same ester is bullsh1t.

Also if you read further back I've highlighted from the Op, that the purpose of esterification is purely to slow release from depot site. Then others have said that the compound is in the blood within hours to a couple of days, and cleaving the ester from position 17 on the hormone is what slows release.???

 

[GetXXL]

Also if you read further back I've highlighted from the Op, that the purpose of esterification is purely to slow release from depot site. Then others have said that the compound is in the blood within hours to a couple of days, and cleaving the ester from position 17 on the hormone is what slows release.???

It's caused by the difference in solubility in oil and water. An ester makes the substance more soluble in oil, and less in water. The longer the ester, the more soluble it is in oil (enanthate is more soluble in oil than propionate, hence the longer half-life of enanthate). If you wouldn't esterize testosterone it would rapidly hit the bloodstream after injection, but because of the esterization, it is slowed down because of the higher solubility in oil (since you inject the compound with an amount of oil, it serves as a depot in the muscle).

I do like maths. Used to do PHP and MySQL web based apps, and at work I've created quite a lot of Excel VBA applications. But saying that, it's the old gigo isn't it. You have know the formula to get the desired result. Been a great thread, and I've achieved the objective of understanding half life from it.

I've recently started webdeveloping with use of PHP/MySQL/javascript/AJAX/CSS. I pick it up very fast since I'm already known with programming (Java and C mainly). It's very easy to program something and make a nice interface around it with this. Really love it.

 

[B|GJOE]

It's caused by the different in solubility in oil and water. An ester makes the substance more soluble in oil, and less in water. The longer the ester, the more soluble it is in oil (enanthate is more soluble in oil than propionate, hence the longer half-life of enanthate). If you wouldn't esterize testosterone it would rapidly hit the bloodstream after injection, but because of the esterization, it is slowed down because of the higher solubility in oil (since you inject the compound with an amount of oil, it serves as a depot in the muscle).

I get that bit, and that version is the 1 that makes sense to me.

What I don't get is why some say Enanthate is a 4 day half life, some 6-8, and I've even seen 12 days for enanthate. I would expect a particular time + or - 25%. But the difference between 4 days and 12 days is + 200%!

 

[GetXXL]

I think you mist this part of a previous post of me:

This is due to what some people interpretet as half-life and active-life. It's common to speak of active-life being two half-lifes past. So if the half-life is 5 days, it's common to speak of an active-life of 10 days (2 * half-life). (keep in mind in this case active-life says absolutely nothing about the substance still being active or not).

Enanthate half-life is approximately 5 days, but people copy paste, errors are made, and so the 10 days are born. The other 1-day marge is pretty much 'cause half-life isn't exactly the same in each person. Half-life could very well be 5 days in person X, yet it could be 6 days in person Y. Half-lifes in literature are always avarages of a group.

And had to Google the word "cleaving" (I'm good at English, but it's still not my native language ), yes that's also a part of what happens, since the "reverse esterification", decreases oil solubility and increases water solubility. It's pretty much like this, you have a substance, with a C-atom, a double-bounded O atom, and another O-atom, and the rest of the actual substance (aka. the esterized substance). You add a H2O molecule, what happens is that an O-H connection is added to the C-atom, and an alcohol is split from the sustance, containing the other H-atom, and the single-bounded O-atom and some of the rest (H-O-R). Hm, sounds weird if I try to describe it.

 

[Mars]

I get that bit, and that version is the 1 that makes sense to me.

What I don't get is why some say Enanthate is a 4 day half life, some 6-8, and I've even seen 12 days for enanthate. I would expect a particular time + or - 25%. But the difference between 4 days and 12 days is + 200%!

If you only use scientific data/sites then the biological half life is always quoted as the the same, IE: test enanthates biological half life IS 5-8 days.
This is worked out using the terminal half (which is found using psuedo equilibrium constant dynamics, which is extremely accurate) from this the half life is workrd out using pseudo equilibrium variable dynamics, this also gives mean resistance times and terminal mean times and from this the terminal active life is also ascertained.
PS, getxxl, i'm not sure were you are coming from with your hypothesis oil and water and the ester as the life is decided by the number of atoms in the side chain and not wether the ester is in oil or water.

 

[B|GJOE]

If you only use scientific data/sites then the biological half life is always quoted as the the same, IE: test enanthates biological half life IS 5-8 days.
This is worked out using the terminal half (which is found using psuedo equilibrium constant dynamics, which is extremely accurate) from this the half life is workrd out using pseudo equilibrium variable dynamics, this also gives mean resistance times and terminal mean times and from this the terminal active life is also ascertained.
PS, getxxl, i'm not sure were you are coming from with your hypothesis oil and water and the ester as the life is decided by the number of atoms in the side chain and not wether the ester is in oil or water.

Thanks Mars.

Just 1 more thing mate.

Where the hell have you been? I thought you had fell of the face of the planet.

 

[GetXXL]

If you only use scientific data/sites then the biological half life is always quoted as the the same, IE: test enanthates biological half life IS 5-8 days.
This is worked out using the terminal half (which is found using psuedo equilibrium constant dynamics, which is extremely accurate) from this the half life is workrd out using pseudo equilibrium variable dynamics, this also gives mean resistance times and terminal mean times and from this the terminal active life is also ascertained.
PS, getxxl, i'm not sure were you are coming from with your hypothesis oil and water and the ester as the life is decided by the number of atoms in the side chain and not wether the ester is in oil or water.

Hm, I do not exactly understand what you mean? But what I meant was that it's a good rule of the thumb that, the more C-atoms the ester contains, the longer the half-life, or isn't that what you meant?

Thanks Mars.

Just 1 more thing mate.

Where the hell have you been? I thought you had fell of the face of the planet.

Maybe my post revived him

 

[B|GJOE]

Maybe my post revived him

Maybe not, he's gone again......

 

[cecil_sensation]

brill read

 

[smurphy]

thanks for sharing information about this.. Now i can buy winstrol

I doubt anyone would buy from you at your prices! Fook me you'd have to be desperate

 

[Imspartacus]

I thought I would give this another look.
I can see why people are confused.
The terms used when discussing half lives are Terminal or elimination, and biological or mean, the sticky is very confusing in this respect as it tries to use the term to differentiate between active life and half life but then lists them as "active half lives" the terminology and the half lives are both wrong.
The half lives listed therefore are not accurate for either of the above hence where I think the confusion lies, it certainly does for me.
Take just a single example, Test Enanthate, according to he science of pharmacokinetics this has a biological/mean half life of approx 7 days, It's terminal/elimination half life is approx 4 days, continuing on It's MRT or (mean residence time) is approx 12 - 14 days, (this is serum level).
There is a 96% reduction (total elimination bar metabolites) after the 5th half life which happens after approx 21 days.

 

[G-G]

I thought I would give this another look.
I can see why people are confused.
The terms used when discussing half lives are Terminal or elimination, and biological or mean, the sticky is very confusing in this respect as it tries to use the term to differentiate between active life and half life but then lists them as "active half lives" the terminology and the half lives are both wrong.
The half lives listed therefore are not accurate for either of the above hence where I think the confusion lies, it certainly does for me.

well you’ve confused the shit out of me with that.

If the mean half life is 7 days and terminal half life is 4 days, how can the 5th half life be 12-14 days?

can I ask where your information has come from? Reason I ask is whatever resource I’ve looked at over the years has advised a half life of test e at approx 10.5 days.

 

[Imspartacus]

well you’ve confused the shit out of me with that.

If the mean half life is 7 days and terminal half life is 4 days, how can the 5th half life be 12-14 days?

can I ask where your information has come from? Reason I ask is whatever resource I’ve looked at over the years has advised a half life of test e at approx 10.5 days.

My apologies, I have written it correctly now.
My Info comes from medical/scientific websites, there is not much point looking for this information anywhere else.
If you look up the page you will see MARS post (thats me, who Simon banned when he found I was still moderating on uk-m lol) which explains the science behind it.
I only ever research scientific/medical papers, you will never find one of these listing a biological half life of TE as approx 10.5 days.

 

[Imspartacus]

If cycling to obtain the necessary supraphysiological levels required for optimum muscle growth I would use the elimination half life and jab my test e every 4-5 days.
I would use the biological half life for TRT.