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Testosterone Replacement, Low T, HCG, & Beyond
Testosterone Basics & Questions
SubQ vs IM (E2)
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<blockquote data-quote="madman" data-source="post: 219703" data-attributes="member: 13851"><p>Whether injected strictly IM or sub-q the esterified T (prodrug) does not aromatize to estradiol until the ester has been cleaved which <strong><em>mainly happens when it enters the bloodstream</em></strong> as you are then left with native/free T.</p><p></p><p><strong><em>*PRODRUG HYDROLYSIS occurs in the blood and the ester is also partly hydrolyzed within the interstitium<strong>"</strong></em></strong></p><p></p><p>Then the magic happens as some will be bound to binding proteins (SHBG, HSA, cortisol-binding globulin, and orosomucoid, binding/activation of androgen receptors, converted by the 5α reductase enzyme to DHT and aromatized to estradiol.</p><p></p><p>I would be more concerned with your protocol (dose T/injection frequency) let alone where your FT level sits than fretting over injecting IM vs sub-q!</p><p></p><p></p><p></p><p></p><p><strong>NEW INSIGHTS INTO DRUG ABSORPTION FROM OIL DEPOTS (2017)</strong></p><p><strong></strong></p><p><strong>CONCLUSIONS</strong></p><p></p><p><em>It is interesting to realize that drug absorption from an oil depot cannot entirely be described by a simple two-phase mass transfer model where concentration gradients, diffusion, and partition coefficients would enable the calculation of the expected absorption. It is demonstrated in this dissertation that there is a role of the excipient BOH in yielding an initially high absorption.<strong> The oil depot forms a continuous phase after injection but will be dispersed and encapsulated at the injection site after some days. This in turn largely influences the way the prodrug becomes available; after release from the oil depot, it is present in the interstitial fluid which is drained through the lymph into the systemic circulation. <u>Subsequently, the prodrug permeates through the wall of blood cells and is hydrolyzed</u>. Both the lymph transport and the cell wall permeation take time which is expressed in a lag time.</strong></em></p><p><em></em></p><p><em><u><strong>This lag time is different for each injection site</strong></u><strong>:</strong> <strong>a subcutaneously administered prodrug</strong> <strong>will enter the systemic circulation via a <u>short path and at a low drainage flow</u>. This results in a <u>short lag time and a slow absorption rate constant of the prodrug</u>.</strong></em></p><p><em><strong></strong></em></p><p><em><strong>Deeper administered prodrugs (i.e. intramuscular injections)</strong> <strong>are suggested to be absorbed via a <u>longer path, but at a higher flow, which results in a longer lag time but a higher absorption rate constant of the prodrug</u>.</strong></em></p><p><em><strong></strong></em></p><p><em><strong>[ATTACH=full]20346[/ATTACH]</strong></em></p><p><strong>Figure 7.2: <u>Schematic overview of the new insights into drug absorption from oil depots</u>. After release from the oil depot (yellow circle at the injection site), the prodrug is transferred towards the central compartment via the lymphatic system. Here, it will be hydrolyzed to the active substance (see circle). ka = absorption rate constant; ke = elimination rate constant.</strong></p><p></p><p></p><p></p><p></p><p>[URL unfurl="true"]https://www.excelmale.com/forum/threads/trt-with-subcutaneous-testosterone-injections-a-safe-practical-and-reasonable-option.24297/#post-210977[/URL]</p><p></p><p><strong>B) <u>Schematic illustration of the absorption steps of testosterone esters after IM (left) or SC (right) injection</u>. With administration using either route, the ester exits the depot via diffusion into the interstitium from where it enters the lymphatics and <u>subsequently reaches the circulation where it undergoes hydrolysis by intracellular esterases</u>. <u>Testosterone ester is also partly hydrolyzed within the interstitium, with free testosterone entering the circulation directly</u>.</strong></p><p><strong></strong></p><p><strong>IM (intramuscular)</strong></p><p><strong>[ATTACH=full]20344[/ATTACH]</strong></p><p><strong></strong></p><p><strong></strong></p><p><strong>SC (subcutaneous)</strong></p><p>[ATTACH=full]20345[/ATTACH]</p></blockquote><p></p>
[QUOTE="madman, post: 219703, member: 13851"] Whether injected strictly IM or sub-q the esterified T (prodrug) does not aromatize to estradiol until the ester has been cleaved which [B][I]mainly happens when it enters the bloodstream[/I][/B] as you are then left with native/free T. [B][I]*PRODRUG HYDROLYSIS occurs in the blood and the ester is also partly hydrolyzed within the interstitium[B]"[/B][/I][/B] Then the magic happens as some will be bound to binding proteins (SHBG, HSA, cortisol-binding globulin, and orosomucoid, binding/activation of androgen receptors, converted by the 5α reductase enzyme to DHT and aromatized to estradiol. I would be more concerned with your protocol (dose T/injection frequency) let alone where your FT level sits than fretting over injecting IM vs sub-q! [B]NEW INSIGHTS INTO DRUG ABSORPTION FROM OIL DEPOTS (2017) CONCLUSIONS[/B] [I]It is interesting to realize that drug absorption from an oil depot cannot entirely be described by a simple two-phase mass transfer model where concentration gradients, diffusion, and partition coefficients would enable the calculation of the expected absorption. It is demonstrated in this dissertation that there is a role of the excipient BOH in yielding an initially high absorption.[B] The oil depot forms a continuous phase after injection but will be dispersed and encapsulated at the injection site after some days. This in turn largely influences the way the prodrug becomes available; after release from the oil depot, it is present in the interstitial fluid which is drained through the lymph into the systemic circulation. [U]Subsequently, the prodrug permeates through the wall of blood cells and is hydrolyzed[/U]. Both the lymph transport and the cell wall permeation take time which is expressed in a lag time.[/B] [U][B]This lag time is different for each injection site[/B][/U][B]:[/B] [B]a subcutaneously administered prodrug[/B] [B]will enter the systemic circulation via a [U]short path and at a low drainage flow[/U]. This results in a [U]short lag time and a slow absorption rate constant of the prodrug[/U]. Deeper administered prodrugs (i.e. intramuscular injections)[/B] [B]are suggested to be absorbed via a [U]longer path, but at a higher flow, which results in a longer lag time but a higher absorption rate constant of the prodrug[/U]. [ATTACH type="full" alt="1647708026475.png"]20346[/ATTACH][/B][/I] [B]Figure 7.2: [U]Schematic overview of the new insights into drug absorption from oil depots[/U]. After release from the oil depot (yellow circle at the injection site), the prodrug is transferred towards the central compartment via the lymphatic system. Here, it will be hydrolyzed to the active substance (see circle). ka = absorption rate constant; ke = elimination rate constant.[/B] [URL unfurl="true"]https://www.excelmale.com/forum/threads/trt-with-subcutaneous-testosterone-injections-a-safe-practical-and-reasonable-option.24297/#post-210977[/URL] [B]B) [U]Schematic illustration of the absorption steps of testosterone esters after IM (left) or SC (right) injection[/U]. With administration using either route, the ester exits the depot via diffusion into the interstitium from where it enters the lymphatics and [U]subsequently reaches the circulation where it undergoes hydrolysis by intracellular esterases[/U]. [U]Testosterone ester is also partly hydrolyzed within the interstitium, with free testosterone entering the circulation directly[/U]. IM (intramuscular) [ATTACH type="full" alt="Screenshot (11534).png"]20344[/ATTACH] SC (subcutaneous)[/B] [ATTACH type="full" alt="Screenshot (11535).png"]20345[/ATTACH] [/QUOTE]
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Testosterone Replacement, Low T, HCG, & Beyond
Testosterone Basics & Questions
SubQ vs IM (E2)
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