I think it’s just the simple mechanism of the medication itself and it is designed to sit in a depot and be released slowly overtime so if you think about it there’s really no logic to dosing more frequently than one week or four or five days bare minimum there’s just no logic to it. SHBG plays absolutely no part in the release from the depot and someone with a single digit SHBG will have the same amount remaining in the depot as I would have ain’t admit to upper range SHBG.
For those who are struggling on TRT
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When you were dosing daily, were you using Subq instead of shallow IM?
I tried both and honestly I felt fantastic on the Xyosted injections as well. I’m not sure why but they absolutely obliterated my lipids when using those subtitueneous injectors as opposed to doing intramuscular. Not really sure the mechanism behind that but it would never improve while on those injectors
@Cataceous
Do you think there is reason to believe that Xyosted has a higher absorption rate than regular TE due to its lack of preservatives and alcohol? The studies shows that 100mg leads to an average level of 900 TT, which seems higher than what people generally report for 100mg regular TE. People generally report the trough though. I can’t grasp my head around why seem people claim they need 150mg sometimes to reach a level like 700TT.
Also, the half life of TC is 8 days I believe, so I would think that two weekly shots of TC is still better than one weekly shot of Xyosted.
Do you think there is reason to believe that Xyosted has a higher absorption rate than regular TE due to its lack of preservatives and alcohol? The studies shows that 100mg leads to an average level of 900 TT, which seems higher than what people generally report for 100mg regular TE. People generally report the trough though. I can’t grasp my head around why seem people claim they need 150mg sometimes to reach a level like 700TT.
Also, the half life of TC is 8 days I believe, so I would think that two weekly shots of TC is still better than one weekly shot of Xyosted.
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tareload
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Intramuscular vs SubQutaneous Injections for Testosterone
100 mg/week of TC IM vs SQ IM modeled as 4.5 day elimination half life and 8 hr absorption half life SQ modeled as 8 day elimination half life and 16 hr absorption half life E7D injections and typical clearance volume… IM is orange and SQ is blue. If you were only looking at trough TT...
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See here.
I like that discussion, but the graphs and charts are not labeled. I am trying to infer which color is IM vs SubQ based on the discussion, but admittedly, I can't tell for sure. Based on 4.5 days vs. 8 days, I assume the lower peaked curve is SubQ.Intramuscular vs SubQutaneous Injections for Testosterone
100 mg/week of TC IM vs SQ IM modeled as 4.5 day elimination half life and 8 hr absorption half life SQ modeled as 8 day elimination half life and 16 hr absorption half life E7D injections and typical clearance volume… IM is orange and SQ is blue. If you were only looking at trough TT...
See here.
Lol same. Those charts are poorly labeled. I was confused what the takeaway was supposed to be other than SubQ is stronger than IM. The TC half life is still 8 days SubQ correct?
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tareload
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Correct, lower peak / higher trough would be the modeled subQ case.
More background.
Intramuscular vs SubQutaneous Injections for Testosterone
The misinformation on here regarding IM vs SQ injections and resulting serum TT levels is staggering but understandable. The area under the curve (AUC) will be invariant to injection method (IM vs SQ) for equivalent testosterone ester dose. There can be a measurable difference in...
forums.t-nation.com
Intramuscular vs SubQutaneous Injections for Testosterone
See below and TU paper above. 4 ml oil injection…i will pass: The PK profile of serum testosterone and its two bioactive metabolites, DHT and E2 in this study indicate that the SC injections of TU displayed no significant differences from the IM route. This is consistent with PK studies of...
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Our thinking is that the absorption rate of Xyosted is lower than it is with other formulations due to the lack benzyl alcohol. This means a longer effective half-life, but does not imply that any less testosterone is absorbed overall. As you and @readalot note, reporting only trough testosterone measurements is problematic when levels are varying significantly during the injection cycle. A figure of 900 ng/dL does seem reasonable for an average serum TT level when on 100 mg/week of enanthate. My own number is over 1,200 ng/dL. The guys needing 150 mg to reach 700 ng/dL at trough may also have low SHBG, which drives down total testosterone.
I'd be more inclined to assign cypionate a nominal half-life of 5 days, based on various information posted by @madman. This makes it little different from enanthate. It is quite a contrast to see a half-life of 10 days reported for Xyosted. This suggests that one needs two injections a week of conventional cypionate or enanthate to be comparable to Xyosted—with respect to the peak and trough levels of serum testosterone.
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tareload
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Haha. Like I continue to he reminded on forums....give somebody a car and they will almost always complain about the color. You have to do a little work yourself. Based on the gory details provided all you could conclude is that SQ is stronger?
@Fortunate
SQ case is on the right:
Added legends to the graph and figure. Thanks for reading and the feedback guys.
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tareload
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To @Cataceous 's point, you can see in the examples above I double the absorption half life of the SQ case vs IM case. In the grand scheme however it is the modeled 8 day elimination half life (SQ) vs 4.5 days (IM) that largely drives the difference.
What do you mean assign it a half life? I thought it was established that TC has a half life of 8 days.
Also, the peak trough ratio for TC for just once weekly based on the above charts appears to be 11:7, which still beats the Xyosted ratio of 2:1. I’d imagine the ratio for TC injections would be even lower on twice weekly injections. I’m not convinced Xyosted has a better PK profile than twice weekly TC injections.
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tareload
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The elimination half life is a range (think normal distribution) like all/many other human/biological characteristics and varies by individual. 4.5 to 7 days for IM and 8 to 10 days for SQ is reasonable for TC. More details I am ignoring....
Bolus oil amount, additives like BA, lymphatic activity, injection location, bodyfat level...
Got it. Thank you for the clarification.
It seems that 5 is too low for the TC half life SubQ.
Pfizer lists the half life of TC as 8 days even for IM. https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/085635s029lbl.pdf
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tareload
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Sure.
Most likely unless you have a physique like this guy or @BigTex ...
The PK data we typically use for SQ is from Xyosted studies which is clouded by the BA as @madman and @Cataceous have pointed out. One man's SQ is another man's IM unless you are pinching the injection site. And some don't have as much to pinch.
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tareload
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Yep. See top two rows of Table 2 in linked post below:
What kind of levels to expect from 100mg weekly
I'm a new to this entire scene, started with levels of around 320, age 40, doctor started me on 100mg once a week. Curious on what type of levels I should expect to see from this? Thanks
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DADT(1)=-KA*A(1)
DADT(2)=K1+KA*A(1)-CL/V*A(2)
CL/V is elimination rate constant or k. See 95% intervals in Table 2.
t1/2 (elimination half life) is ln(2)/k.
For example, k = 2.42/11.9 = 0.203 1/day
t1/2 = 0.693 / 0.203 = 3.4 days (low side)
Another example, k = 2.8 / 17.6 = 0.159 1/days
t1/2 = 0.693 / 0.159 = 4.4 days
I gravitate toward 4 days vs 8 days based on my own shallow IM data and this more comprehensive study.
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tareload
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I put some more comments and calcs in above post for you. You mean better as is more constant profile? Flatter with lower peak and higher trough than IM for a 7 day injection interval?
That’s a great question and I’m not exactly sure what I meant by how it’s better.
I think the fact that there is lower peak-troughs and that you’re less likely to feel “gassed” on the day before you’re next injection. I’ve heard people complain (and I ve had this experience as well using Xyosted) that people feel tired and more blah on Day 6/7 of Xyosted.
I am more confident of this conclusion on 2x weekly TC schedule.
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