Has anyone seen visual charts showing how testosterone levels change between TRT injections?
I'm curious whether the curves are smooth or if there are sharp peaks/drops, especially for the common esters like cypionate and enanthate.
Just looking to see what the typical pharmacokinetic profile looks like visually.
I found this post, but would like some more examples if available!:
Pharmacokinetic Profile of Subcutaneous Testosterone - Excel Male Health Forum
Regarding half-lives keep in mind that a majority of studies on the PK/PD of the various T-esters were done using IM (once weekly/fortnightly) injections in a small number of subjects and most of the literature is from decades ago.
Top it off that blood samples were generally collected once per day at a consistent time not every few hrs over a 24 hr period.
The 2019 Kaminetsky 52-week phase III study injecting TE strictly sub-q (Xyosted auto-injector) more frequent sampling was done during pharmacokinetic assessment.
Over a 24 hr period blood draws were done at predefined intervals (0, 2, 4, 8, 12, 24) then 48, 72, 96,120, 144, and 168 hours post-dose.
There is not going to be a big difference in the PKs (TC vs TE) although TC is slightly longer acting they are basically interchangeable.
There is. lots of misinformation out there littered on the forums/net regarding the half-life TC which is shorter than many think.
TE/TC are basically interchangeable and the half-life of TC is not 8 days.
TE: 7-carbon aliphatic ester side-chain
TC: 8-carbon aliphatic ester side-chain
T levels will start rising fairly quick even when using the medium-chain esters.
There will be a burst release of T within 2 hrs post-injection and true peak can be achieved within 24 hrs even as soon as 8-12 in some cases!
Depending on the dose injected T levels will be high/very high post-injection (peak/during the first few days) as once Tmax is achieved levels decline gradually over the following days.
Increasing your injection frequency clips the peak--->trough let alone keeps blood levels more stable throughout the week.
There is going to be a big difference in peak--->trough injecting once weekly vs twice-weekly vs daily.
Even then when looking at the PKs injecting once weekly there can be high be variability in T levels (peak/trough) between men.
Even then much more to the story here!
My reply from an older thread:
I would not fret over whether one uses enanthate vs cypionate as they are basically interchangeable.
Regardless of the minor differences in the esters between the two, there are many other factors that affect the rate at which testosterone is released from the oily depot at the injection site.
Sub-q vs IM, the volume of injection, injection depth, site of injection, lymphatic flow, and the concentration of BOH (benzyl alcohol) is other possible factors that can affect absorption rates of the esterified hormone.
As far as testosterone esters 100 mg of enanthate= 72 mg active testosterone and 100 mg cypionate= 70 mg active testosterone.
Would not even waste my time getting too caught up on the PKs.
If anything I would be far more concerned with your protocol (dose T/injection frequency)/SHBG level and where such has your trough FT levels!
Figure 5.
Schematic overview of the pharmacology of testosterone esters. Testosterone is esterified through the 17 β hydroxyl group with fatty acid esters of different aliphatic or other chain length which is a biologically inactive pro-drug.
The esterified testosterone in an oil vehicle is injected deeply into a muscle forming a local drug depot from which the testosterone ester is released at a slow rate determined by its physico-chemical partitioning according to the testosterone ester’s hydrophobicity. Once the testosterone ester exits the depot and enters the extracellular fluids, it is rapidly hydrolyzed by ubiquitous non-specific esterases thereby releasing the testosterone into the general circulation.
SWIFT
They are basically interchangeable!
COMPARISON OF TESTOSTERONE, DIHYDROTESTOSTERONE, LUTEINIZING HORMONE, AND FOLLICLE-STIMULATING HORMONE IN SERUM AFTER INJECTION OF TESTOSTERONE ENANTHATE OR TESTOSTERONE CYPIONATE (1980)
MECHTHILD SCHULTE-BEERBUHL, CAND.MED. EBERHARD NIESCHLAG, PROF.DR.MED.*
However, since no comparison of the serum testosterone levels achieved by injection of testosterone enanthate or cypionate in equivalent doses has been reported, it is undecided which of the two esters produces the longer-lasting effects and the more favorable plasma...
COMPARISON OF TESTOSTERONE, DIHYDROTESTOSTERONE, LUTEINIZING HORMONE, AND FOLLICLE-STIMULATING HORMONE IN SERUM AFTER INJECTION OF TESTOSTERONE ENANTHATE OR TESTOSTERONE CYPIONATE (1980)
MECHTHILD SCHULTE-BEERBUHL, CAND.MED. EBERHARD NIESCHLAG, PROF.DR.MED.*
FIG. 1. Effect of 140 mg of testosterone injected either as enanthate (e) or cypionate ester (0) on serum hormone levels of six normal men. To convert testosterone values from nanomoles per liter (SI units) to nanograms per 100 ml the results must be divided by 0.0347; for DHT the factor is 0.0345.
Regarding half-lives keep in mind that a majority of studies on the PK/PD of the various T-esters were done using IM (once weekly/fortnightly) injections in a small number of subjects and most of the literature is from decades ago.
Here is a more recent and in-depth study using TC.
Population Pharmacokinetic/Pharmacodynamic Modeling of Depot Testosterone Cypionate in Healthy Male Subjects (2018)
Youwei Bi Paul J. Perry Touro University California, [email protected] Michael Ellerby Touro University California, [email protected] Daryl J. Murry...
Population Pharmacokinetic/Pharmacodynamic Modeling of Depot Testosterone Cypionate in Healthy Male Subjects (2018)
Youwei Bi1, Paul J. Perry1,2, Michael Ellerby2 and Daryl J. Murry3
Look over post #4/5 (PKs different T formulations)
Does Patient-Applied Testosterone Replacement Therapy Pose Risk for Blood Pressure Elevation? Circadian Medicine Perspectives (2022)
Michael H. Smolensky, Ramon C. Hermida, Linda Sackett-Lundeen, *Ramon G. Hermida-Ayala, and Yong-Jian Geng
ABSTRACT
We reviewed medication package inserts, US Food and Drug Administration (FDA) reports, and journal publications concerning the 10 nonbiosimilar patient-applied (PA) testosterone (T) replacement therapies (TRTs) for intraday serum T patterning and blood pressure (BP) effects. Blood T concentration is circadian...
PK Testosterone Propionate (1976/1986)
It's important to be aware that the measurements in this study were only once a day, at 8:00. The injection was at 18:00. So in reality Tmax could occur much sooner than 14 hours post-injection. My experience with propionate at low doses (<10 mg) is at least suggestive of a Tmax under six hours.
MADNESS!
Indeed!
Bioavailability and LH-Suppressing Effect of Different Testosterone Preparations in Normal and Hypogonadal Men (1976)
Pharmacokinetic Properties of Testosterone Propionate in Normal Men (1986)...
Case Study: Absorption of Testosterone Cream via Scrotal Delivery.
Needham S1, Needham S2.
1Moses Lake Professional Pharmacy, Moses Lake, Washington. 2Alturas Analytics in Moscow, Idaho.
Abstract
Transdermal testosterone has been used for years to treat patients with low testosterone symptoms. Clinically, we have monitored patients to evaluate results of testosterone absorption via blood serum concentrations. The data on multiple time points to determine trough and peak concentrations is lacking in the literature. In this case study, we demonstrate the absorption of...
Case Study: Absorption of Testosterone Cream via Scrotal Delivery (2018)
Needham S, Needham S.
Moses Lake Professional Pharmacy, Moses Lake, Washington. Alturas Analytics in Moscow, Idaho.
Conclusion
*we concluded that the scrotal administration of testosterone in a cream formulation provides high bioavailability, dose-dependant peak serum testosterone concentration, and tolerability with a much lower dose relative to the non-scrotal transdermal route
*further studies of extended duration will be required to fully evaluate the clinical application of this new scrotal testosterone formulation
Pharmacokinetics of testosterone cream applied to scrotal skin (2017)
*R. Iyer, *S. F. Mok, S. Savkovic, L. Turner, G. Fraser, R. Desai, V. Jayadev, A. J. Conway and D. J. Handelsman
MP85-14 VARIANCE IN PEAK AND TROUGH TESTOSTERONE LEVELS IN MEN USING INTRAMUSCULAR TESTOSTERONE
Bruno Nascimento*, Helen L Bernie, Elizabeth Schofield, John P. Mulhall, New York, NY
INTRODUCTION AND OBJECTIVES
In men using intramuscular testosterone (IM T), clinical experience shows us that, despite stable dosing and frequency, total testosterone peak (Tp) and trough (Tt) levels are highly variable, thus challenging the clinician to make a decision regarding dose adjustments. The goal of this study was to define...
MP85-14 VARIANCE IN PEAK AND TROUGH TESTOSTERONE LEVELS IN MEN USING INTRAMUSCULAR TESTOSTERONE
Bruno Nascimento*, Helen L Bernie, Elizabeth Schofield, John P. Mulhall, New York, NY
CONCLUSIONS
In our population of patients on stable IM T dose, there was a wide mean variation in both Tp (23%) and Tt (17.5%). In addition to that, 25% of patients had a maximum Tp change greater than 50% and a maximum Tt change greater than 35%. Clinicians should be aware of this high variability in levels when deciding on dose adjustment.
Look over post #5/7-10 (PKs different T formulations)
Abstract Context: Injections with intramuscular testosterone esters have been available for almost 8 decades and not only result in predictable serum testosterone levels but are also the most inexpensive modality. However, they are difficult to self-administer and associated with some discomfort. Recently, subcutaneous administration of testosterone esters has gained popularity, as self-administration is easier with this route. Available data, though limited, support the feasibility of this route. Here we review the pharmacokinetics and safety of subcutaneous testosterone therapy...
Look over post #3 (PKs different T formulations)
Abstract
Background: To improve symptoms associated with testosterone deficiency (TD), many testosterone therapies (TTh) are available that aim to restore serum testosterone (T) levels to the normal physiologic range. The magnitude, frequency, and duration between peak and trough T concentrations vary with route of administration, and none reflect normal endogenous daily diurnal T variations.
Objective: To compare pharmacokinetic (PK) profiles of serum T from approved T formulations with endogenous diurnal T variations in young and older men, and to consider whether...
PK Xyosted (Sub-q TE Auto-injector)
Notice when looking at the graph for Panel A.....
during weeks 6 and 12 testosterone levels peak 10 hrs post injection followed by dip and than a second peak at 36 hrs when using
testosterone enanthate (TE Auto-Injector).
