Some results from my Depo-T Absorption Calculator

[ASaxon]

Determined to understand the dosing of Depo-T I created a absorption calculator in Excel that calculates the absorption levels of Depo-T over time and graphs the daily concentrations of Active T in the blood. I did this so I could see the difference between the various dosing possibilities. I’d post the graphs but I don’t have a location to host the charts so I’m just including the summary numbers. It's interesting to see how doubling the first dose helps stablize T-levels very quickly as opposed to just starting the regular dose.

Note: These values are only after treatment on a dose for at least 45 days so that ramp up values are not evaluated. These calculations assume a Depo-T half-life of 8 days as published.

On 100mg every 7 days we have:
18.251 - Maximum Daily Concentration (mg)
14.244 - Average Daily Active Concentration (mg)
9.951 - Minimum Daily Concentration (mg)
8.300 - Change in Concentrations During Cycle (mg)

On 200mg every 14 days we have:
23.622 - Maximum Daily Concentration (mg)
14.257 - Average Daily Active Concentration (mg)
7.599 - Minimum Daily Concentration (mg)
16.023 - Change in Concentrations During Cycle (mg)

On 150mg every 7 days we have:
27.377 - Maximum Daily Concentration (mg)
21.366 - Average Daily Active Concentration (mg)
14.927 - Minimum Daily Concentration (mg)
12.449 - Change in Concentrations During Cycle (mg)

On 300mg every 14 days we have:
35.433 - Maximum Daily Concentration (mg)
21.385 - Average Daily Active Concentration (mg)
11.398 - Minimum Daily Concentration (mg)
24.035 - Change in Concentrations During Cycle (mg)

On 200mg every 7 days we have:
36.502 - Maximum Daily Concentration (mg)
28.488 - Average Daily Active Concentration (mg)
19.903 - Minimum Daily Concentration (mg)
16.599 - Change in Concentrations During Cycle (mg)

On 400mg every 14 days we have:
47.244 - Maximum Daily Concentration (mg)
28.514 - Average Daily Active Concentration (mg)
15.197 - Minimum Daily Concentration (mg)
32.047 - Change in Concentrations During Cycle (mg)

Just thought I’d post this. I’m still analyzing various dosing amounts and schedules but it’s interesting that my current dose of 400mg every 14 days has a swing in concentrations twice as much as 200mg every 7 days, which makes sense.

Scott

[ASaxon]

Oh and here’s the dosing for a steroid user.

A dose of 1000mg every 7 days.
182.511 - Maximum Daily Concentration (mg)
142.440 - Average Daily Active Concentration (mg)
99.515 - Minimum Daily Concentration (mg)
82.996 - Change in Concentrations During Cycle (mg)

Interesting!

Scott

[wildfox]

Interesting. How about for smaller amounts more frequently?

WF

[ASaxon]

I posted some more frequent doses but something's screwy with the calculator when using less than a 7 day cycle. I'll figure it out and post the results.

UPDATE:

Figured it out.

I can only do whole day cycles so putting in a cycle of 3.5 days gives a 7 day cycle so I had to do a 3 day cycle and a 4 day cycle then average the results. Here’s what I got.

On 75mg every 3 days:
27.044 - Maximum Daily Concentration (mg)
24.605 - Average Daily Active Concentration (mg)
22.404 - Minimum Daily Concentration (mg)
4.640 - Change in Concentrations During Cycle (mg)

On 75mg every 4 days:
21.135 - Maximum Daily Concentration (mg)
18.562 - Average Daily Active Concentration (mg)
16.132 - Minimum Daily Concentration (mg)
5.003 - Change in Concentrations During Cycle (mg)

Averaging we get (for 75mg every 3.5 days):
24.090 - Maximum Daily Concentration (mg)
21.584 - Average Daily Active Concentration (mg)
19.268 - Minimum Daily Concentration (mg)
4.822 - Change in Concentrations During Cycle (mg)

Likewise, averaging 50mg every 3.5 days we get:
16.060 - Maximum Daily Concentration (mg)
14.389 - Average Daily Active Concentration (mg)
12.845 - Minimum Daily Concentration (mg)
3.214 - Change in Concentrations During Cycle (mg)

That you go.

I’m pretty sure these are correct but if you notice anything strange let me know.

Scott

[pmgamer18]

I am not sure what your doing but it looks like every 3 or 4 days is better not so high so less E2 problems. If I am wrong tell me.

[Ruper]

I'd really like to know the time to the peak (I assume an exponential decay after the peak).

I guess I could just calculate it from your numbers, but it would be easier to ask. (EDIT - I'm guessing the peak is ~24 hours after injection?)

Also do you ramp linearly to the peak, or use some other function?

Any idea (anyone) on the range of extra T 250IU of hCG will give for someone who is secondary - or is that just a huge variation.

[Ruper]

Originally Posted by ASaxon

Just thought I’d post this. I’m still analyzing various dosing amounts and schedules but it’s interesting that my current dose of 400mg every 14 days has a swing in concentrations twice as much as 200mg every 7 days, which makes sense.

Scott

Yes, it's easy to come to the conclusion that if you have to exceed 100mg every week by much, then you might be better off doing less every 3-4 days instead.

[chap]

How about the concept that the published 8 day half life is completely wrong.
Also the concept that the absorption of a steroid ester is not linear.

Interesting exercise in spreadsheet skills, but I think the real life application of the data is not useful.

[ASaxon]

Originally Posted by Ruper

I'd really like to know the time to the peak (I assume an exponential decay after the peak).

I guess I could just calculate it from your numbers, but it would be easier to ask. (EDIT - I'm guessing the peak is ~24 hours after injection?)

Also do you ramp linearly to the peak, or use some other function?

Any idea (anyone) on the range of extra T 250IU of hCG will give for someone who is secondary - or is that just a huge variation.

My calcs are based on how much Depo-T is absorbed into the body. The formula to calculate how much Depo-T remains in the body from a single injection is:

y=(original dose) * 1 / 2 ^ ((Day number after inject)/(half life in days))

Note: the ^ symbol means raised to the power of.

I see no point in putting in 24 or 48 hour ramp up curve at the beginning of this as after you reach peak you will just decay as if the peak was immediate. There would be a small difference as the amount of Depo-T present at a peak 48-hours after injection would be slightly less than the injected amount but I don’t think by that much. Plus, I just want to get a accurate estimate not an actual 100% accurate model.

So if you wanted to find out how much Depo-T (with a half life of 8 days) was left form a 100mg injection after 5 days you’d calculate it as:

y = 100 * 1 / 2 ^ ( 5 / 8 )

y = 100 * 0.6484

y = 64.84 mg

So after 5 days a 100mg injection roughly has 64.84mg of Depo-T that has not been activated via enzyme activity. This also means that 35.16 mg has been activated over that 5 day period.

You also have to remember that if someone was to inject another 100mg at 5 days the total Depo-T in their system would then be 100 + 64.84 = 164.84 mg just waiting to be cleaved by enzyme action into active T. As we all know this means that injections overlap in their absorption into the body so figuring out the actual absorption of all Depo-T in the body form all active injections is the process by which we can determine how much actual Depo-T we absorb and activate on any one day.

The calculator I created looks at the overlapped dosing to get the total absorbed from day to day.

Scott

[ASaxon]

Originally Posted by chap

How about the concept that the published 8 day half life is completely wrong.
Also the concept that the absorption of a steroid ester is not linear.

Interesting exercise in spreadsheet skills, but I think the real life application of the data is not useful.

Pfizer states in there Depo-T patient information sheet that:

“The half-life of testosterone cypionate when injected intramuscularly is approximately eight days.” (source: http://www.pfizer.com/pfizer/downloa...stosterone.pdf)

And the decay I use is not linear…sorry!!!