Natural T vs. Test Cyp.

[McBeavy]

I'm sure this has been answered here before but I searched and can't find the answer.

The question I have is: Normal males produce around 4-7 milligrams of natural testosterone per day, so that works out to 28-49mgs per week. Why do we tend to use so much more, say testosterone cypionate, when we're on T replacement? Is test cyp not as "strong" as biological T?

 

[Cataceous]

This has been discussed in detail, but here's a quick recap from my perspective: First, testosterone cypionate is only 70% testosterone, so you need 70 mg of it to get the 49 mg of T per week. The testosterone in cypionate is bioidentical, meaning once it's loose your body can't tell it apart from natural T. Next, let's be generous and say that the full range of natural production is 3-9 mg per day. This corresponds to 30-90 mg T cypionate per week. Also, because testosterone cypionate does not provide normal diurnal variation in serum testosterone you have to increase the dose by ~20% to achieve the same peak levels. With this calculation you get a maximum dose of about 110 mg TC per week. This is in line with the Xyosted product, which is injectable testosterone enanthate. The only doses available are 50, 75 and 100 mg per week. Enanthate has only slightly more testosterone than cypionate. A final factor is the injection frequency. If you're injecting frequently—daily or EOD—then serum levels usually don't fluctuate too much. But if you're injecting once weekly then you can have large swings in serum testosterone, with peaks as much as 2.5-3 times larger than troughs. To put the troughs at minimum acceptable levels may require increasing the dose to over ~100 mg/week. However, this usually results in supraphysiological peaks.

This part is speculative: There are guys who insist they need supraphysiological dosing to feel good. If this is the case then perhaps the excessive dosing is compensating for the disruptions caused by TRT. For example, in some cases high doses may compensate for excessive estradiol, as eventually the aromatase enzyme starts to saturate and you can reduce your E2/T ratio. Of course there's the very real possibility of creating other imbalances, and the long-term safety is uncertain.

 

[tareload]

This has been discussed in detail, but here's a quick recap from my perspective: First, testosterone cypionate is only 70% testosterone, so you need 70 mg of it to get the 49 mg of T per week. The testosterone in cypionate is bioidentical, meaning once it's loose your body can't tell it apart from natural T. Next, let's be generous and say that the full range of natural production is 3-9 mg per day. This corresponds to 30-90 mg T cypionate per week. Also, because testosterone cypionate does not provide normal diurnal variation in serum testosterone you have to increase the dose by ~20% to achieve the same peak levels. With this calculation you get a maximum dose of about 110 mg TC per week. This is in line with the Xyosted product, which is injectable testosterone enanthate. The only doses available are 50, 75 and 100 mg per week. Enanthate has only slightly more testosterone than cypionate. A final factor is the injection frequency. If you're injecting frequently, daily or EOD, then serum levels usually don't fluctuate too much. But if you're injecting once weekly then you can have large swings in serum testosterone, with peaks as much as 2.5-3 times larger than troughs. To put the troughs at minimum acceptable levels may require increasing the dose to over ~100 mg/week. However, this usually results in supraphysiological peaks.

This part is speculative: There are guys who insist they need supraphysiological dosing to feel good. If this is the case then perhaps the excessive dosing is compensating for the disruptions caused by TRT. For example, in some cases high doses may compensate for excessive estradiol, as eventually the aromatase enzyme starts to saturate and you can reduce your E2/T ratio. Of course there's the very real possibility of creating other imbalances, and the long-term safety is uncertain.

For those that may want a picture to back up what @Cataceous so eloquently said.

Above what weekly dosage does the upper confidence line (97.5 percentile) start to venture outside the green shaded area? What about the 50 percentile line?

We have baby growth charts. Now you have TOT/TRT dose response charts. Enjoy!

Tool to Assess your TT Dose Response -- Percentile Curves

Summary: Tools to estimate your individual dose response for injectable testosterone ester in comparison to a normal distribution (95 percentile confidence estimate) of adult males (Ref). Plot below shows a summary of data from (1) clinical trials gathered from the literature + (2)...

forums.t-nation.com

What is TRT and What is NOT TRT

Note: I originally posted this over at T-Nation so hope it's ok if I share it here @Nelson Vergel. Had an interesting and lively exchange over there with one of the proponents of the "TOT" protocol (Testosterone Optimization Therapy as it is called). This short summary gives guys a look of...

www.excelmale.com

Thanks for the explanation @Cataceous.

 

[Vince]

Keep It Up: The Power of Precision Medicine to Conquer Low T and Revitalize Your Life! Hardcover October 8, 2013 by Florence Comite - I read this book a couple of years ago and thought it was really good. I read the kindle version. She talks about men feeling their best, when having their testosterone levels, at the levels they were, when they were young. She believes young men should have their levels tested, so when they get older they know what to shoot for.

 

[McBeavy]

Thank you for the detailed replies.

Once again, this site overwhelms me with the generous knowledge shared here.