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Thread: 1/2 Life of Testosterone Myth? Injecting every 2 weeks is better?

  1. #1
    jdjr is offline New Member
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    1/2 Life of Testosterone Myth? Injecting every 2 weeks is better?

    I've been lurking here for months after my doctor put me on 400mg of Testosterone Cypionate every 2 weeks. I've asked if it is OK to split that into weekly doses and he had not problem with that. I've seen the 1/2 life graph on here and read explanations on why weekly injections or even more frequent are better.

    I then cama across a rebuttal to this on the "Center for Men's Health" web site that shows that every 2 weeks is "better", (more test after 7 days, than a weekly dose)

    Since I can't post a URL here is what it said...

    The half life is the point at which the drug in plasma is reduced by 50%.
    The half life of Depo-Testosterone is 8 days.

    Now “simple” logic would lead one to believe that at twice the ½ life (16 days) there would be ZERO
    (0%) of the injected testosterone in your plasma but that is NOT THE CASE as half life science is not
    that simple……as that mathematical formula above indicates.

    The half life formula for Depo-Testosterone in plasma states that at 8 days you would have 50% of the
    initial dose remaining, at 16 days you would have 25% of the initial dose, at 24 days it would be 12.5%,
    at 32 days 6.25% and so on.

    The 14 day protocol 200mg treatment (standard C4MH dose): at 8 days =100mg’s remaining, 16 days =
    50 mg’s, 24 days = 25 mg’s. At 14 days you would still have 62.5mg’s of active Depo –Testosterone
    in plasma.

    The 7 day protocol 100mg treatment (standard dose): at 7 day = 57 mg’s remaining of active DepoTestosterone
    in plasma.

    So at 200mg/14 days (C4MH protocol) you have an active 100mg’s in plasma at 8 days and
    at the 100mg / 7day protocol you have an active 57mg’s at 7 days.


    Clearly the 7 day protocol makes ZERO medical sense……and any perceived
    difference is truly placebo.



    Seems to make sense to me, but I'm still injecting weekly

    Thanks,
    John

  2. #2
    DocToxin8's Avatar
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    You are mistaking the amount of testosterone left in the oil depot in the muscle with plasma/serum/blood testosterone.

    In blood, testosterone has a half life of minutes.
    As a depot in oil, in the muscle or fat (if SubQ), it has a somewhat stable half
    Life, but it fluctuates a lot also.

    When you have 100mg test cyp in your system that means there's 100mg test cyp in an oil depot in a muscle. Not that you have 100mg test cyp in your bloodstream.

    Frequent injects hinder spikes in absorption from the oil depot and gives smoother blood levels of T.

  3. #3
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    The 14 day protocol 200mg treatment (standard C4MH dose): at 8 days =100mg’s remaining, 16 days =
    50 mg’s, 24 days = 25 mg’s. At 14 days you would still have 62.5mg’s of active Depo –Testosterone
    in plasma.
    The point being? For optimal treatment stable concentrations of hormones are desired, not "different than zero".

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    Once test cyp or test enanthate or any ester is released to the blood,
    esterases quickly cleave of the fatty acid attached.
    Test propionate becomes testosterone + propanoic acid.
    The fatty acid is used for energy and the free testosterone acts just like your natural testosterone. And if it isn't bound to albumin or SHBG it's destroyed very quickly.

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    DocToxin8's Avatar
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    Furthermore, to elaborate on my first post.
    Let's say you inject 400mg test e in your glutes,
    and you then go running or squatting or whatever that trains the gluteus.
    This will cause a spike in absorption.
    You also get a spike in absorption at day 1&2 after injecting.

    More frequent injects of less mgs causes smaller spikes.
    Thus more stable T values.

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    redz's Avatar
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    To optimize stable blood levels and minimal side effects every week is better than every two and twice a week is even better still. There is simply no way that injecting less frequently is superior in any way.

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    Couchlock is offline Banned
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    Quote Originally Posted by jdjr View Post
    I've been lurking here for months after my doctor put me on 400mg of Testosterone Cypionate every 2 weeks. I've asked if it is OK to split that into weekly doses and he had not problem with that. I've seen the 1/2 life graph on here and read explanations on why weekly injections or even more frequent are better.

    I then cama across a rebuttal to this on the "Center for Men's Health" web site that shows that every 2 weeks is "better", (more test after 7 days, than a weekly dose)

    Since I can't post a URL here is what it said...

    The half life is the point at which the drug in plasma is reduced by 50%.
    The half life of Depo-Testosterone is 8 days.

    Now “simple” logic would lead one to believe that at twice the ½ life (16 days) there would be ZERO
    (0%) of the injected testosterone in your plasma but that is NOT THE CASE as half life science is not
    that simple……as that mathematical formula above indicates.

    The half life formula for Depo-Testosterone in plasma states that at 8 days you would have 50% of the
    initial dose remaining, at 16 days you would have 25% of the initial dose, at 24 days it would be 12.5%,
    at 32 days 6.25% and so on.

    The 14 day protocol 200mg treatment (standard C4MH dose): at 8 days =100mg’s remaining, 16 days =
    50 mg’s, 24 days = 25 mg’s. At 14 days you would still have 62.5mg’s of active Depo –Testosterone
    in plasma.

    The 7 day protocol 100mg treatment (standard dose): at 7 day = 57 mg’s remaining of active DepoTestosterone
    in plasma.

    So at 200mg/14 days (C4MH protocol) you have an active 100mg’s in plasma at 8 days and
    at the 100mg / 7day protocol you have an active 57mg’s at 7 days.

    Clearly the 7 day protocol makes ZERO medical sense……and any perceived
    difference is truly placebo.

    Seems to make sense to me, but I'm still injecting weekly

    Thanks,
    John
    See here, your going to have a severe flux of levels at 14 days. Up a and down

    Yes at 8 days an injection of 400 will be 200.

    And at day 15 100

    So in 2 weeks you go down 75% in test (I'm,just using basic numbers as example, not actual circulating plasma levels)

    If you took the 200 every week, you'd have this

    At day 8 you'd be at 100, and also receiving another shot adding to bring you back up to 200 you never have more than a 50% drop.

    And its also adding to the already present 100.

    In the 400 every 2 weeks your adding 400 to the 100 and causing a extreme flux over time

  8. #8
    kelkel's Avatar
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    Your doc is injecting you with a cycle dosage. Do blood work on day 2 or 3 and then on day 14. See the difference.
    It's all about blood work and how you feel. Extreme levels do not equal hormone replacement.
    You'll also have massive estrogen conversion with such large injections resulting in more issues to mitigate.
    Take some time and read articles by some of the top men in this field, Crisler, Vergel, etc.
    -*- NO SOURCE CHECKS -*-

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    Quote Originally Posted by jdjr View Post

    So at 200mg/14 days (C4MH protocol) you have an active 100mg’s in plasma at 8 days and
    at the 100mg / 7day protocol you have an active 57mg’s at 7 days.

    Here is why there are wrong.
    They are comparing day 8 of the 200mg to day 7 of the 100mg protocol.

    On day eight of the 100mg protocol you would be injecting again so....
    200mg protocol day 8 is 100mg in plasma vs
    100mg protocol day 8 is 150mg in plasma.

    More frequent injections equals lower highs but higher lows.

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    jdjr is offline New Member
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    Thanks!

  11. #11
    jdjr is offline New Member
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    Thanks,

    48 hours after injection I was 1168ng/dl and Free T was 377ng/dl

    Quote Originally Posted by kelkel View Post
    Your doc is injecting you with a cycle dosage. Do blood work on day 2 or 3 and then on day 14. See the difference.
    It's all about blood work and how you feel. Extreme levels do not equal hormone replacement.
    You'll also have massive estrogen conversion with such large injections resulting in more issues to mitigate.
    Take some time and read articles by some of the top men in this field, Crisler, Vergel, etc.

  12. #12
    kelkel's Avatar
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    Quote Originally Posted by jdjr View Post
    Thanks,

    48 hours after injection I was 1168ng/dl and Free T was 377ng/dl

    And possibly still rising, metabolism dependent.
    -*- NO SOURCE CHECKS -*-

  13. #13
    Youthful55guy is online now Knowledgeable Member
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    Quote Originally Posted by jdjr View Post
    48 hours after injection I was 1168ng/dl and Free T was 377ng/dl
    These numbers just don't seem right to me, particularly with a 400 mg dose of T-cyp. I'm wondering if anyone else sees the same thing, or is there something I'm missing. I'll be the first to admit, I don't know everything about TRT.

    Here's a kinetic curve for T-eth and T-cyp. The data shows that the kinetics of T-cyp and T-eth are very similar. Three healthy men aged 20-29 received 194 mg of T-eth followed 7 weeks later by 200 mg T-cyp and then vice versa. The publication claims n=6, but it was actually n=3 in a cross-over design, but for argument sake, we'll go with n=6. they used the unusual number of 194 mg T-eth in order to equalize the amount of molecular T that was delivered in each injection. T-eth has a slightly lower molecular weight of the ester side chain than T-cyp, so it delivers slightly more T per mg solution than T-cyp, hence the need for correction.

    1/2 Life of Testosterone Myth? Injecting every 2 weeks is better?-t-cyp-kinetic-curve-2.png
    Data source: Behre, H.M., and Nieschlag, E. (1998). Comparative pharmacokinetics of testosterone esters. In Testosterone: Action - Deficiency - Substitution, E. Nieschlag, and H.M. Behre, eds. (Berlin, Heidelberg: Springer Berlin Heidelberg), pp. 329-348.

    Note that the original paper only published the blood levels in nmol/L and I converted it to ng/dL and added the second axis. As you can see, a 200 mg injection of either T-Cyp or T-Eth results in a peek blood level in 24 to 48 hours of around 1,400 ng/dL. I don't have normal values for the same age group, but for 50-60 age group Lab Corp normal values are 348-1197 ng/dL. It is safe to say from this data that at 200 mg per injection, resulting Testosterone blood levels exceed the upper end of normal physiological range by about 200 ng/dL, and exceed midrange values by about 700 ng/dL. If you inject 400 mg as you have done, I would anticipate the 24-48 hour blood levels to be much higher than 1168 ng/dL.

    The second thing that struck me as very odd was the Free T level. Typically, at least in the USA, Free T is expressed in pg/mL. Below are the Lab Corp Free T reference ranges for various age groups.
    * 20-29 years 9.3-26.5 picogram/mL
    * 30-39 years 8.7-25.1 picogram/mL
    * 40-49 years 6.8-21.5 picogram/mL
    * 50-59 years 7.2-24.0 picogram/mL
    * 60+ years 6.6-18.1 picogram/mL

    In order to convert ng/dL to pg/mL, you move the decimal one place to the right, so 377 ng/dL would be 3,770 pg/mL, which is a very, very large number. Perhaps I'm not doing the conversion correctly (again, I am by no means an expert), but the numbers just don't look right to me. Please, if anyone sees an error in my logic or calculations, please chime in.

  14. #14
    kelkel's Avatar
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    I would agree it seems quite low. I wonder if we both misread the op 55guy? He said he asked his doc if he could split the dose from 400 E2W to 200 EW. If the latter is much more pallatable.

    The op needs to clear this up.
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    LeeSin1 is offline Junior Member
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    I did it every two weeks and my levels were always the same at the end of the 2 weeks, so it ran out before then. Every week has been much better for me.

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    Quote Originally Posted by jdjr View Post
    Thanks,

    48 hours after injection I was 1168ng/dl and Free T was 377ng/dl
    Impossible if was injected 400mg, unless very poor injection technique leading not to inject in muscle.

    The OP probably mixed the numbers, and is getting the outdated protocol of 200mg every 2 weeks.

  17. #17
    jdjr is offline New Member
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    The results of that blood test were after 200mg/week for at least 6 months. Prior Blood test ( 4 months ago ) had me at 960


    Quote Originally Posted by Mr.BB View Post
    Impossible if was injected 400mg, unless very poor injection technique leading not to inject in muscle.

    The OP probably mixed the numbers, and is getting the outdated protocol of 200mg every 2 weeks.

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