Understanding Esters, Active-Life and Half-Life

[Prodiver]

Also, if the whole subject is so friggin confusing, and highly complicated mathematically then why the hell are all these bodybuilders just banging in the same doses at the same arbitrary time (ie 1 week).

Surely you want a cycle to have roughly the same active hormone in the blood for a specified duration. Weekly injections will not achieve this. Active hormone in the body will be all over the place, especially taking things like sustanon on a 7 day rota.

Talk about people blindly following the same trite spewed by the masses.

In the land of the blind the one eyed man will be king!

Sorry, I'm either being thick or just keenly inquisitive.

Indeed. The only real way to determine dose is to have your test levels checked periodically, as we do on TRT, and have the dose adjusted. Other factors like hematocrit can be monitored carefully then too.

However, it does turn out that endocrinologists know with a fair degree of confidence that 250 mg test every 14, 10 or 7 days will achieve the desired levels safely - that's what Sus etc. were designed for.

 

[Prodiver]

Well I suppose that makes some sense, which is why the half lives quoted in the op are for the ester, NOT the hormone. But I'm still no sure I understand why the body uniformly strips the ester in half life fashion, if it does, which I think it doesn't. I'm inclined to go with the 500mg from 1g after 10 days, then 400, then the rest as you said earlier.

Half lives are not designed into drugs or hormones - they are simply a testament to the fact that many functions in the body - as in nature - decay exponentially.

 

[B|GJOE]

Here we go again

Look at the quoted half life's of Cyp, Enth, and Deca below from Anabolic Steroid Esters by Bill Roberts

What are the half-lives of different esters?

Shorter chain esters have shorter half-lives, because of their lower partition coefficient. Testosterone cypionate has a half-life of 8 days5, the enanthate ester has a half-life of 4 days6, and nandrolone decanoate has a half-life of 8 days7. These figures are only approximate. The difference between these values for cypionate and enanthate probably includes difference attributable to different measuring techniques. The actual difference is probably not more than two days.

In the rat, where half-lives of anabolic steroid esters are similar to those in humans but somewhat shorter, the half-lives of the phenylpropionate, decanoate, and laurate esters are 1, 5, and 10 days respectively.3 The same trend would be expected in man.

Half-life is linearly related to log partition coefficient, which is itself linearly related to the carbon chain length, the exception being if the ester is an unusual one such as phenylpropionate. This was shown by James et al.3 for the formate through valerate esters of testosterone in the rat. The half-life of testosterone propionate was approximately 4 days, and each carbon added to or subtracted from that chain length changed half-life by about 1.5 days.



Read more from this MESO-Rx article at: Anabolic Steroid Esters by Bill Roberts

I recommend you read the full article above.

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[B|GJOE]

Now this one really got me thinking......

The active life of a steroid is the amount of time that the drug is still delivering you anabolic effects in the body. For some orals, active life can be just a few hours. For some oil-based testosterone esters, it can be weeks. The amount of time can vary from person to person, based upon metabolism and a wealth of other factors, so active life should never be the sole determinant in any decision making regarding steroid use. What is important to you are a person injecting testosterone and maintaining artificial T levels is to know that you need to make each injection just before the effectiveness of a drug stops. At that point, your testosterone levels will plummet, estrogen levels will fluctuate, and you’re in for a world of lost muscle and energy and the potential emergence of gyno. Know your active lives, and plan your cycles accordingly.

Half life is much easier to understand. Its use isn’t as dire as active live, but it is very useful when making calculations for knowing when drugs will be out of your system so that you can be clean for employment or competition testing. The half life of a steroid is the amount of time it will take for the active life to be halved in the body.

Source:Half Life, Active Life & AAS | Steroids Today .com

The way that reads is as follows:

If I have a drug that has an active life of 10 days for example, and a half life of 5 days then.....

in 5 days the active life would be 5 days.

in 5 more days the active life would be 2.5 days

in 5 more days the active life would be 1.25 days.

and so on..............


which is a bit more complex than the old drug mg halves every so often.

 

[Prodiver]

Blood plasma concentration is the only measure of how much of a drug exists in the body.

So I'd bet the half life is the time taken for blood plasma concentration to be halved.

This is probably taken fron the peak value, which occurs after a latency period of some hours after first administration.

Half life is a statistical value simply used to estimate dose times to maintain a desired plasma concentration.

 

[Greyphantom]

Now this one really got me thinking......


Source:Half Life, Active Life & AAS | Steroids Today .com

The way that reads is as follows:

If I have a drug that has an active life of 10 days for example, and a half life of 5 days then.....

in 5 days the active life would be 5 days.

in 5 more days the active life would be 2.5 days

in 5 more days the active life would be 1.25 days.

and so on..............


which is a bit more complex than the old drug mg halves every so often.

Joe you made my head hurt... thats way to complex for a dope like me, imho I think half lives (ie dose halfing each x time) will do me...

 

[Stephen]

Now this one really got me thinking......


Source:Half Life, Active Life & AAS | Steroids Today .com

The way that reads is as follows:

If I have a drug that has an active life of 10 days for example, and a half life of 5 days then.....

in 5 days the active life would be 5 days.

in 5 more days the active life would be 2.5 days

in 5 more days the active life would be 1.25 days.

and so on..............


which is a bit more complex than the old drug mg halves every so often.

that's pretty much exactly how it's calculated Joe, no different in essence from decay times used when looking at radiation.

Do we really need to understand the exact mg content though, as this does not take into account receptor sensitivity or the directly linked increase in estrogen, cortisol etc, before we even start looking at the latest theory that myostatin will increase throughout a cycle!

It's obviously handy to have an understanding of esters but IMO around 95% of bodybuilding chemical science is guess work based on the small amounts of empirical data available in studies and then applying them to our real life scenarios.

I couldn't agree more with your point though about the blind following the blind, I'm not a clever guy by any means but I put a bit of thought into what I do, the amount of people I see or speak to doing 1 sust, 1 deca for 6 weeks cos some big guy in the gym said so gives me the watery bowk I'm so sick of it!

 

[GetXXL]

I didn't read all comments, but it appears some people struggle with the entire half-life idea being an exponential breakdown rather than linear.

Imagine being on a shooting range, having 1000 targets at random in front of you. If you simply spray and pray on the shooting range, you'll hit a lot more targets a lot faster if there are 1000 instead of 10 for example. So imagine it takes you 5 minutes to take down the first 500 targets. Now after those 5 minutes of spraying, there are only 500 targets left, instead of 1000, you won't just shoot the remaining 500 targets in another 5 minutes by just spraying around. You'll most likely hit another 250 targets in another 5 minutes, etc. Maybe a bad example, but maybe this is a 'breakthrough' for some people

I'd also like to clarify the esterification (sorry if this has been done already in this thread, didn't read all comments). Testosterone in it's free form hits the bloodstream rapidly and will be gone within hours after injection, as it is water soluble. The esterisation makes it soluble in oil. So when you inject, the testosterone won't rapidly hit the bloodstream, because of the esterification the testosterone has more 'affinity' (don't know if it's the right word to use in this context, language barrier ) for the oil. The longer the ester, the better the testosterone will be soluble in oil, so the longer it stays in the depot. This is better known as an "afscheidingscoëfficiënt" in Dutch, the term for the ratio between oil and water solubility. Google Translate gives me "partition coefficient", god may know if that's the correct translation for it. And the more C-atoms an ester has, the better soluble it is in oil (hence the longer half-life for the testosterone distribution). Although more C-atoms doesn't necessarily mean a better solubility, it's also dependent on structural factors, but it's a good rule of the thumb.

The amount of testosterone is for nearly 100% dependent on the release of the ester (in case of oral steroids it's for nearly 100% dependent on the liverpassage). So that's why we can calculate it pretty efficiently knowing the half-lifes of the esters.

 

[B|GJOE]

I didn't read all comments, but it appears some people struggle with the entire half-life idea being an exponential breakdown rather than linear.

Imagine being on a shooting range, having 1000 targets at random in front of you. If you simply spray and pray on the shooting range, you'll hit a lot more targets a lot faster if there are 1000 instead of 10 for example. So imagine it takes you 5 minutes to take down the first 500 targets. Now after those 5 minutes of spraying, there are only 500 targets left, instead of 1000, you won't just shoot the remaining 500 targets in another 5 minutes by just spraying around. You'll most likely hit another 250 targets in another 5 minutes, etc. Maybe a bad example, but maybe this is a 'breakthrough' for some people

I'd also like to clarify the esterification (sorry if this has been done already in this thread, didn't read all comments). Testosterone in it's free form hits the bloodstream rapidly and will be gone within hours after injection, as it is water soluble. The esterisation makes it soluble in oil. So when you inject, the testosterone won't rapidly hit the bloodstream, because of the esterification the testosterone has more 'affinity' (don't know if it's the right word to use in this context, language barrier ) for the oil. The longer the ester, the better the testosterone will be soluble in oil, so the longer it stays in the depot. This is better known as an "afscheidingscoëfficiënt" in Dutch, the term for the ratio between oil and water solubility. Google Translate gives me "partition coefficient", god may know if that's the correct translation for it. And the more C-atoms an ester has, the better soluble it is in oil (hence the longer half-life for the testosterone distribution). Although more C-atoms doesn't necessarily mean a better solubility, it's also dependent on structural factors, but it's a good rule of the thumb.

The amount of testosterone is for nearly 100% dependent on the release of the ester (in case of oral steroids it's for nearly 100% dependent on the liverpassage). So that's why we can calculate it pretty efficiently knowing the half-lifes of the esters.

No disrespect mate, but you should've read the entire thread. I get what you said, but it is the inconsistencies, and different versions of events and calculated times that is causing me the biggest issue. Also, with you analogy multiple injections will effect half life:

For example, you are spraying 1000 targets and it takes 5 minutes to reduce that figure to 500. But if you add another 1000 targets at around the 3 minute mark, then you will have approx 1700 targets being sprayed, does this mean that 5 minutes from this point you will be down to 850?

Either I am over complicating something that is simple, or it is in fact a very complicated subject.

 

[GetXXL]

No disrespect mate, but you should've read the entire thread. I get what you said, but it is the inconsistencies, and different versions of events and calculated times that is causing me the biggest issue. Also, with you analogy multiple injections will effect half life:

For example, you are spraying 1000 targets and it takes 5 minutes to reduce that figure to 500. But if you add another 1000 targets at around the 3 minute mark, then you will have approx 1700 targets being sprayed, does this mean that 5 minutes from this point you will be down to 850?

Either I am over complicating something that is simple, or it is in fact a very complicated subject.

In case of the same ester, yes.

And it doesn't effect the half-life, it stays 5 minutes in this case.

 

[B|GJOE]

In case of the same ester, yes.

I thought so, therefore it is more complicated than the simplistic versions floating around.

I am sure that most users, actually think that injection 1 has it's own half life independent of subsequent injections.

 

[GetXXL]

I thought so, therefore it is more complicated than the simplistic versions floating around.

I am sure that most users, actually think that injection 1 has it's own half life independent of subsequent injections.

It doesn't matter at all, imagine you inject 500mg, with a half-life of 2 days. So after 2 days you have 250mg left.
Then you inject another 500mg, with the same half-life of 2 days, so after 2 days there will be 250mg left of that depot, and after 2 days there will be 125mg left of the other depot. Which is 375mg in total. If you simply added the amounts you'd yield the same results, 500+250mg = 750mg. So after 2 days, it's once again 375mg which is left.

Or isn't this what you meant?

 

[B|GJOE]

It doesn't matter at all, imagine you inject 500mg, with a half-life of 2 days. So after 2 days you have 250mg left.
Then you inject another 500mg, with the same half-life of 2 days, so after 2 days there will be 250mg left of that depot, and after 2 days there will be 125mg left of the other depot. Which is 375mg in total. If you simply added the amounts you'd yield the same results, 500+250mg = 750mg. So after 2 days, it's once again 375mg which is left.

Or isn't this what you meant?

LOL, isn't maths just beautiful. Numbers always follow patterns.

It works when you inject at the half life point, but what about if you do it before half life.

So in your example.

Day 0 500
Day 2 250+500 =750
Day 4 375
Day 6 187.5
Day 7 Would be approx 140.625

Right now lets inject again before half life, and we get.....
Day 0 500
Day 1 375 Approx + 500 = 875
Day 3 437.5
Day 5 218.5
Day 7 109.25

Now if we keep injecting before half life, the maths gets even more complex. Add to this the fact that I have seen sources for the same ester quote half lives with massive differences, i.e. Enanthate 4 days to 12 days.

 

[GetXXL]

Day 1 isn't 375. What you're doing right now is making it linear between the half-lifes themselves, and exponential on the half-lifes. Use 1/(2^n), with n the amount of half-lifes past. In this case 0.5 (1 day, instead of 2), so 1/(2^0.5) = 1/(sqrt(2))
1/(sqrt(2)) * 500 = 250 * (sqrt(2)) = 353.something instead of 375. You're making a math error.

Add to this the fact that I have seen sources for the same ester quote half lives with massive differences, i.e. Enanthate 4 days to 12 days.

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.

 

[B|GJOE]

Day 1 isn't 375. What you're doing right now is making it linear between the half-lifes themselves, and exponential on the half-lifes. Use 1/(2^n), with n the amount of half-lifes past. In this case 0.5 (1 day, instead of 2), so 1/(2^0.5) = 1/(sqrt(2))
1/(sqrt(2)) * 500 = 250 * (sqrt(2)) = 353.something instead of 375. You're making a math error.

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