Definitive Test E Half-Life?

[Equinob]

I've googled all over the internet looking for something definitive, and can't really seem to find two reliable sources that agree on the answer to this.

There seem to be two camps: the 4-5 day camp, and the 8-11 day camp.

I'm trying to calculate my PCT start date, but for a drug that's been around as long as this, I'm having a hard time getting a reliable figure to use. I know it's only a guideline as each person metabolizes it differently and bloods are the only way to know for sure when to optimally start, but still, this is a pretty wide window. At the moment I'm splitting the difference using 7 days which gives me a 21 day waiting period, but that could either be way too long, or way too short based on my research.

 

[Wunderpus]

The Half Lives of the Most Popular Anabolic Steroids and Bodybuilding Drugs

 

[Equinob]

The Half Lives of the Most Popular Anabolic Steroids and Bodybuilding Drugs

Thanks. I saw that. Roberts seems to be in the 5 day camp.

I also saw this posted by Northern Nutrition indicating up to 7 days:
Education on esters

And a paper published by Dr. John Crisler shows up to 8 days.

And in the article Pharmacokinetics and Pharmacodynamics of Steroid Esters by Dr. Michael Scally, he suggests 7-12 days.

That's a lot of conflicting expert opinions.

 

[Wunderpus]

I use 5 days as a genera rule of thumb to be safe. Better under estimate, than over I assume.

 

[bdg77]

From what I understand about steroid half-lives it's a little more complex than say a pill or tablet. I wish I could find a post I read on some other board where it was explained much better than I can. I'll try to find it, but here's what I can remember in a nutshell. It started off with someone looking at a test-c molecule. The question was about the half-life in relation to the eight carbon ester. Was it broken down one carbon at a time? Answer: No, the whole ester is cleaved at once. How does the ester affect the half-life? Answer: The longer the ester the more fat soluble it is. Which keeps it in depot and fatty tissue longer. Now here's where it gets complicated. At least to me, maybe a good doc or someone can explain it better. But the big question is why doesn't all the test get released at once. Which most of it might but some sooner and some later. Geez, I feel lke I'm digging myself in a hole right now. As it was explained much better. Basically there are a lot of factors. Like metabolism, depot volume/concentration, etc. Which is why the half-life has a wide range. As far as pct I think your pretty close with your middle-road approach. Although your going to know when your test starts to crash after test-e. So you might need to adjust your time accordingly.

 

[xupc]

Testosterone Enanthate: 4.5 days

The formula used for calculating the rate of compound release at a given day t is:

λ * N(t)
Where λ is the decay constant equal to ln(2)/h, h being the half life of the compound given in days; and N(t) is the half-life equation given by:

N(t) = n * e^(-t/λ)
Where n is the original dose of the compound in mg and t is given in days.

Behre HM, Nieschlag E. 1998 Comparative pharmacokinetics of testosterone esters. In: Nieschlag E, Behre HM, eds. Testosterone: Action, Deficiency, Substitution, ed 2. Berlin: Springer-Verlag; 329–348.

 

[bdg77]

When I do a search I get answers from as low as 4.5, 5.25, 5.5, 8 up to 10.5. So what's the deal am I reading old outdated stuff or what. Then again it's not surprised, I can't a straight answer for anything on the net nowadays. There's always two opposing arguments that both seem to make sense and I end up wanting to bang my head on the wall.

 

[xupc]

When I do a search I get answers from as low as 4.5, 5.25, 5.5, 8 up to 10.5. So what's the deal am I reading old outdated stuff or what. Then again it's not surprised, I can't a straight answer for anything on the net nowadays. There's always two opposing arguments that both seem to make sense and I end up wanting to bang my head on the wall.

The article is not old or outdated. If a piece of work has produced a new contribution the work does not get repeated. The halflife is 4.5 days. I cant understand why you are struggling?

 

[bdg77]

I'm not struggling at all. It's just there are a lot of opinions out there. And if there is one thing I know it is people respond differently to steroids. And I get leary when I see things regarding biology explained with simple equations. If that's correct then that changes a lot of info that I believed to be accurate. And that information does not answer the question. That's just a formula to use after the variables are known. It is the accuracy of the variables we are wondering about.

 

[xupc]

I'm not struggling at all. It's just there are a lot of opinions out there. And if there is one thing I know it is people respond differently to steroids. And I get leary when I see things regarding biology explained with simple equations. If that's correct then that changes a lot of info that I believed to be accurate. And that information does not answer the question. That's just a formula to use after the variables are known. It is the accuracy of the variables we are wondering about.

It is extremely simple to calculate half life of drugs. It is not rocket science. The half life is 4.5 days. Read the paper for more information.

 

[bdg77]

If you say so. I really have no reason or evidence to doubt what your telling me. But then why do half-lives of drugs have such wide ranges? Like differing ranges of 400-500% in some cases. Valium for example has it's half-life in the range of 20-80hrs. Up to 50-200 hours in some listings. What accounts for the wide range. I realize it has active metabolites that have half-lives of their own. So why isn't it as straight forward as it should be?

 

[bdg77]

I've thought about it for a little while and 4-5 days sounds reasonable. I was trying to factor in why it can build up at once a week. It works there too. Now if the big question wasn't what is actually in my bottle. We could have tons of empirical data which would shed some light on what should be trivial questions. With the increased interest of trt all of this will become clear.

 

[InquisitiveT]

So, on another thread here on meso-rx, I was sort of reading into this same thing. Doc on this forum says 5-7 for half life and he suggest start PCT at ~day 21. This would put your test e levels back to a low level; low enough that a SERM will be effective. Most people stick to starting PCT at day 14 after last pin, but it looks like your Test levels are still too high at day 14 that a SERM would be effective. Just my 2 cents, not an expert opinion, but just based on what I've read.

Thread where I've read this: Proper way to inject HCG

 

[Dr JIM]

The half life of T-e varies but much like those who INSIST on an "optimal" E-2 level, if one compiles all the studies who investigated this issue and perform a "meta-anaylsis" we find the half-life for T-e is;
6.72309 DAYS, or 161.35 HOURS, or 9681.2496 SECONDS

I hope this facilitates your perfectly timed PCT.

None of that means SQUAT unless your perform POST-PCT LABS to determine if such "timing" was prolonged enough to enable HTPA recovery!

 

[Dr JIM]

SIMPLIFIED PCT no calculator or meta-analysis required

Roughly 3-4 weeks after the LAST T-e injection, begin SERM tx.

Run the SERMS for another 3-4 weeks (or LONGER if desired) and STOP.

Wait at least one week for the SERMS to clear and draw an LH and TT level

IF the levels have returned to your PRECYCLE baseline (you did conduct pre-cycle labs didn't you?) then it's reasonable to assume HTPA recovery has occurred, if such is NOT the case, continue the SERM TX.

PCT failure?
SERM tx is run to EARLY not enabling the clearance of ALL AAS
SERM tx duration is TO SHORT not allowing time for HTPA recovery to occur
The SERMS agents being used are of poor quality, often being purchased over the net thru some IndoChina UGL manufacturer!
The most common cause IME is a failure to conduct CONFIRMATORY LABS !!!

Good luck!

 

[Dr JIM]

Oh it's also perfectly reasonable to perform a TT level before the onset of PCT. The level SHOULD at least approximate that of pre-"TRT" values (300ng/dl) or LOWER, before PCT is started.

PCT may be started sooner BUT, folk need to understand it will only be minimally effective (if at all) with NON-TRT TT levels.

WHAT is the above based upon? Data on the use of SERMS as agents for TRT patients whom suffer from secondary hypogonadism.

 

[Dr JIM]

If you say so. I really have no reason or evidence to doubt what your telling me. But then why do half-lives of drugs have such wide ranges? Like differing ranges of 400-500% in some cases. Valium for example has it's half-life in the range of 20-80hrs. Up to 50-200 hours in some listings. What accounts for the wide range. I realize it has active metabolites that have half-lives of their own. So why isn't it as straight forward as it should be?

Using CARBON decay time as a measure of a DRUGS half life assumes far to much, such as; linear pharmacokinetics, a singular injection, "equalized" partitions coefficients, protein binding capacity, normalized hepatic metabolism and renal excretion of metabolites etc, for use on a clinical basis.

Otherwise the differences in the literature are the result of EXACTLY what has been studied bc the serum half life is actually a reflection of multiple metabolic processes and for this reason half life RANGES SHOULD and WOULD be expected for essentially all drugs.

If you want to know more i'd suggest you check out (Wiki is fine for starters IMO) how a drugs VOLUME of DISTRIBUTION and the PARTITION COEFFICIENT can effect it's half life.

 

[Dr JIM]

Also check out 0, 1st and 2nd order kinetics.

 

[EbFS]

So @Dr JIM I'm on the 19th day after last pin of test cyp. Originally I had planned to run my PCT following the standard 14 days after, then I read somewhere that it's only after 3 or 4 half lives that the TT levels go low enough for SERMs to be effective. This thread confirmed that however on that very same read I found that the half life of cyp was 12 days and based on that data I was planning to wait 36 days. Luckily I found this thread and prevented myself from waiting too long. My question is this, according to your meta-analysis what is the average half life of test cyp? I'm guessing 8-9 days?
Thanks in advance for your answer.
Oh, I ran a test only cycle for 12 weeks 450 mg per week

 

[Dr JIM]

So @Dr JIM



what is the average half life of test cyp?

I'd suggest 7 days for the purposes of PCT.