Dose Reduction: Linear or Not? How to calibrate?

[eyeheartny]

I am in the middle of a trial of transitioning from TRT using cypionate to propionate. The goal was to try to beat some water retention I'd been struggling with for years. I'm working with Ben Walker at Defy Medical. I have a consult with him tomorrow but just got some labs in and I would like some thoughts/advice.

I started with discontinuing cyp on 10/22 (last shot on an EOD regimen, 40mg EOD) and felt amazing for the first day or so. Ben had RXed propionate 20mg/day ED or 40mg EOD. I went to 20mg ED for stability. Within a few days I started to feel a noticeable decline in sleep quality, decrease in libido, and general sense of fatigue. While Ben had suggested a 3 month trial, I knew something was wrong. I had labs drawn on 11/7 and just got them back today. Blood draw was 8 hours after my last Propionate injection.

Total T	Free T	E2 (Sensitive)
1192 ng/dL (ref. 264-916)	33.5 pg/mL (ref 8.7-25.1)	53 pg/mL (ref 8.0-35.0)

If I'd like to target the top of the range (916), or let's say 85% of the top of the range (778), is a reasonable way to go reducing the dose by the equivalent percentage? So if I'm 30% over the top of the range for total T right now and I reduce my dose by 30%, is it reasonable to expect that I'll settle close to that value? Or is this not as linear as I'm making it out to be?

Thanks!

 

[Cataceous]

Back up a little: Do you have lab results from when you were stabilized on EOD cypionate, including SHBG? What dose(s)? If you have this then you're in good shape and can make make some decent estimates about what's going on with propionate. I've been through the same and found that ED propionate was giving relatively large swings in testosterone, and presumably estradiol as well. In fairly static conditions (e.g. EOD cypionate) you can expect a pretty linear response in Tru-T calculated free testosterone versus dose. From this and SHBG you can go the other direction to make predictions about total testosterone.

With propionate I think one is better off measuring trough values, because it's uncertain exactly when the peak occurs. The trough and a previous calibration with cypionate can be used to estimate the peak value.

 

[eyeheartny]

Back up a little: Do you have lab results from when you were stabilized on EOD cypionate, including SHBG? What dose(s)? If you have this then you're in good shape and can make make some decent estimates about what's going on with propionate. I've been through the same and found that ED propionate was giving relatively large swings in testosterone, and presumably estradiol as well. In fairly static conditions (e.g. EOD cypionate) you can expect a pretty linear response in Tru-T calculated free testosterone versus dose. From this and SHBG you can go the other direction to make predictions about total testosterone.

With propionate I think one is better off measuring trough values, because it's uncertain exactly when the peak occurs. The trough and a previous calibration with cypionate can be used to estimate the peak value.

Thanks for the speedy reply! Lab values from before here, I'm not sure why I came in so low as I think that was a weird draw. For these I was on EOD cypionate.

October 8

Total T	588 ng/dL (ref 264-916)
Free T	14.2 pg/mL (ref 8.7-25.1)
E2 Sensitive	30.5 pg/mL (ref 8.0-35.0)
SHBG	25.7 nmol/L (ref 16.5-55.9)

I felt sort of ok, not great at this amount. I had lowered my dose to 40mg EOD on cyp from 44mg EOD to see if it helped at all with water retention and how I felt running a little lower. What's weird is that I had other bloodwork at another lab a few weeks prior that had me over the range at the same dose on the same schedule.

September 24

Total T	1002.92 ng/dL (ref 123-813)
Free T	205 pg/mL (ref 47-244)

 

[Vince Carter]

Its not linear in that way none of this is. Reduce by 2mg and retest and stay consistent on the time you inject and the time you have your blood draw, use the same lab, etc etc...this will give you better comparability side-by-side with results. Every time you deviate in any way you introduce those variables that break up the comparison's.

 

[Cataceous]

Although discrepancies between labs aren't unusual, these two are so much different that one is likely to be wrong. But here's how the technique works: Using the LabCorp data, your Tru-T free testosterone would be 20.6 ng/dL at a dose of 98 mg testosterone per week. This measurement would be used to predict your average testosterone response to any dose of any ester. Applying the idea to 20 mg T propionate ED, with a weekly testosterone dose of 117 mg, the predicted average free testosterone is proportionally higher, 24.6 ng/dL. Assuming SHBG is unchanged, predicted average total testosterone is about 700 ng/dL. But your measurement with propionate is 70% higher, which is unrealistic and suggests the reading of 588 ng/dL on cypionate is too low. The measurement from the other lab is probably closer to the mark, but I would not try to combine results from different labs to make predictions.

As for what to do going forward, you can keep things simple if your SHBG isn't changing much: just assume that average serum testosterone is proportional to dose. Calculate dose according to daily or weekly testosterone content, noting that cypionate is 70% testosterone and propionate is 83.7% testosterone. With propionate, if you get a trough measurement then you can see how much it is below the predicted average. The peak should be roughly the same amount above the average.

In spite of Vince Carter's skepticism, there is linearity, with free testosterone essentially proportional to dose, as my own measurements demonstrate:

 

[eyeheartny]

Although discrepancies between labs aren't unusual, these two are so much different that one is likely to be wrong. But here's how the technique works: Using the LabCorp data, your Tru-T free testosterone would be 20.6 ng/dL at a dose of 98 mg testosterone per week. This measurement would be used to predict your average testosterone response to any dose of any ester. Applying the idea to 20 mg T propionate ED, with a weekly testosterone dose of 117 mg, the predicted average free testosterone is proportionally higher, 24.6 ng/dL. Assuming SHBG is unchanged, predicted average total testosterone is about 700 ng/dL. But your measurement with propionate is 70% higher, which is unrealistic and suggests the reading of 588 ng/dL on cypionate is too low. The measurement from the other lab is probably closer to the mark, but I would not try to combine results from different labs to make predictions.

As for what to do going forward, you can keep things simple if your SHBG isn't changing much: just assume that average serum testosterone is proportional to dose. Calculate dose according to daily or weekly testosterone content, noting that cypionate is 70% testosterone and propionate is 83.7% testosterone. With propionate, if you get a trough measurement then you can see how much it is below the predicted average. The peak should be roughly the same amount above the average.

In spite of Vince Carter's skepticism, there is linearity, with free testosterone essentially proportional to dose, as my own measurements demonstrate:
View attachment 8634

Interesting, and many thanks for the help and detailed reply. I'm not necessarily following how you got to the "your Tru-T free testosterone would be 20.6 ng/dL at a dose of 98 mg testosterone per week" figure. I see that at 40mg EOD on Cyp I'm at 98mg/week of testosterone after accounting for ester weight, so that makes sense. And I follow your math about calculating the ester-weight adjusted dose of propionate. Where I lose you is the 20.6 ng/dL figure.

Can you help me understand how you arrived at that number? I so appreciate your help.

 

[Vince]

I think a good dose would be 16 mg daily. For me that would be a good starting point.

 

[Cataceous]

Interesting, and many thanks for the help and detailed reply. I'm not necessarily following how you got to the "your Tru-T free testosterone would be 20.6 ng/dL at a dose of 98 mg testosterone per week" figure. I see that at 40mg EOD on Cyp I'm at 98mg/week of testosterone after accounting for ester weight, so that makes sense. And I follow your math about calculating the ester-weight adjusted dose of propionate. Where I lose you is the 20.6 ng/dL figure.

Can you help me understand how you arrived at that number? I so appreciate your help.

If you follow the Tru-T link then you'll find that the page requests total T and SHBG. At 98 mg T per week you measured total T of 588 ng/dL and SHBG of 25.7 nMol/L. The resulting calculated free testosterone is 20.58 ng/dL. The idea is that the injected dose drives free testosterone in a linear manner, as supported by my own data. When SHBG is pretty constant then the injected dose would appear to drive total testosterone in a fairly linear manner as well.

 

[eyeheartny]

If you follow the Tru-T link then you'll find that the page requests total T and SHBG. At 98 mg T per week you measured total T of 588 ng/dL and SHBG of 25.7 nMol/L. The resulting calculated free testosterone is 20.58 ng/dL. The idea is that the injected dose drives free testosterone in a linear manner, as supported by my own data. When SHBG is pretty constant then the injected dose would appear to drive total testosterone in a fairly linear manner as well.

Whoops, I missed the link and thought it was one of those advertising links that some forums insert automatically! Got the link now and what you're saying makes perfect sense.

I just had my consult with Ben Walker and I'm going to drop my dose down by 35% of the propionate and retest bloodwork after a week to give myself a chance to settle in to the lower dose. I'll add SHBG to that round of labs to get a picture of where I am on the propionate.

I will likely repost in this thread and seek your counsel then! In the meantime, many many thanks.

 

[Vince Carter]

you need 6 weeks on a dose change to stabilize

retest bloodwork after a week

 

[Cataceous]

you need 6 weeks on a dose change to stabilize

There's room for debate on this: It probably takes three to four weeks for cypionate to clear the system and no longer affect serum testosterone, but @eyeheartny is about there. The propionate should stabilize in less than a week, meaning that the serum profile of each day looks the same, but there's still the potential for substantial peaks and troughs. Only if "stabilize" is meant to include "feel all the effects of" would you be looking at six weeks or even longer.