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Question on 'Peak and Trough' Testing

My Endo is insisting on peak and trough testing to try and determine if my dosage needs to be changed.

I’ve been on TRT (200mg/ml every 2 weeks, split into 2 .25ml doses per week SC) for the past 2 months. I’ve had to “go it alone” because the Endo will not allow SC, only IM injections.

I’m concerned that my dosing schedule is going to screw up the tests as he is expecting levels related to 200mg IM every 2 weeks. These results will dictate whether my dosage is changed.

How should I dose to give a more “correct” result for the Endo? Something on par for what he expects.

The peak test is supposed to be 1 week after my next “prescribed” dose of 200mg. The trough test is 1 week after that (before my next dose).

I know this may be confusing, but I really appreciate your time.

How about adjusting your schedule so the the trough is one day before injection and the peak is a day after? Your levels will be pretty steady with your scheduling, so when the results come in, be sure to tell your doctor how great he is that he managed to stabilize your testosterone levels.

Peak is two days after.

Tell doc that you are injecting the amount that is prescribed, but that you are injecting it more often to get closer to a natural state. Ask him to prove that injecting every two weeks and better and what the rational is for that. Tell him that what the labs show are not changing much, so peak-trough is not beneficial for you. [never ,ever, heard that line before]

Your 100mg/week levels should be high normal. But your balance with E2 is a huge factor, where is that? Perhaps in some other post there this post of yours should have been. Keep one thread please :wink: as per the advice for new guys sticky.

Thanks, KSman. I’m just asking the question to get some idea of how to get the levels more in line with what he wants to see on those tests.

This guy has already shown that he doesn’t really know what he is doing, so my telling him anything that doesn’t agree with what he already thinks will just confuse and piss him off. He is very “by the book” and has said many of the same things others here have experienced.

I’m afraid he will suspend my T prescription all together since he is under the impression that it is a “controlled substance” and he’s “going way out on a limb by prescribing it” in the first place. It took ALOT of persuading on my part to get it written eve though my levels indicate I definitely need it.

He absolutely will not test my E2 levels and will not prescribe HCG while I’m on T, so you see where I’m coming from. I’ve really got no other options right now as no other doc I’ve talked to will agree and no referrals from compounding pharmacies have helped thus far. No “nudges” towards understanding docs from members here either.

On a side note, how should I append my previous posts to add info or ask a new question? Edit the subject of my opening post and add the info? I’ll be happy to do so, but please elaborate on how you guys would rather it be done.

If is good to have the everything in the opening post, later lab results would then be a new post in the thread.

Where are you located?

It’s interesting that he would order a “peak test” one week after injection, since test cyp peaks at 48-72 hours. Also, it has a 7 day half-life, so you would already be at half the starting dose at that time; 100mg for you if you were injecting 200mg/week. Hardly the peak.

I agree with you that he sounds like he’s not very informed on the topic. If you feel like any pressing on him may get him to cancel your prescription, maybe it’s time to find a new doc or at least start shopping around. I had a couple of endos that I had to see connected to some pituitary issues and none of them were very informed on TRT. It’s sad, really. They were all great guys and great doctors. Just not too spun up on TRT.

But here is where we are. Not sure how long you have until your blood test, but since he’s the guy writing the scripts and calling the shots (unfortunately), we need to play by his rules. Here is a calculator to see how many mgs are running through your system at any given time. You’ll still need to change your schedule for the trough test.


Input your values as you’ve been doing for the past couple of months (50mg 2x/week) to see where you’re at, then input values for the protocol he prescribed (100mg 1x/week) to see where you WOULD be if that’s what you were doing. Adjust accordingly.

Good luck,

The roidcalc seems confusing, I don’t think that the definitions are clear. I entered 14.3 mg every day [100mg/day] and the results were somewhat above the assumed average T delivery in mg’s/day for young normal males. So it might be useful for estimating mg delivery per day. But what we are really wanting to see is serum levels, numbers closer to 800-900. While the mg delivery per day may in theory be very predictable, serum levels are heavily dependant on liver condition, body weight and many other factors that are known and unknown.

Rates of T delivery and the number of mg’s in serum are not the same either. The half life of T in serum is a separate factor from half life of the injected ester. From our point of view and how we feel, knowing that SHBG+T is inert, we would be more interested in response curves for bio-T or free-T. With injections once a week, a given 7 day old TT levels may feel a lot worse than a change in TT suggests. The drop in bio-T may correlate better to what guys feel after 7 [or 14] days.

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I’m in North Carolina near Greensboro.


It was a bit confusing to me as well. I was trying to figure out a method for him to determine exactly how many MGs he had in his system so he could mimic the amount of MGs he SHOULD have in his system. I don’t know of a better way of matching serum levels short of blood tests. Still not sure when his blood test is, but if he stays on his current dosing schedule one of two things will happen. 1) his levels will be high and his doc will lower the dosage, or 2) he will figure out that he has been following his own dosing schedule and cut him out completely.

Pinion has already said that he thinks it is a “controlled substance” and he’s “going way out on a limb by prescribing it”. Don’t want to instigate him. Or, maybe, this isn’t such a bad thing, because I’m not very hopeful that Pinion will have a successful TRT experience with this endo, anyway.

Thanks for the vote of confidence, Kaynon311;) My “peak” test is on 12-27 and the “trough” test is 6 days later on 1-2.

I don’t know why this guy is so hard to work with, but I need to stay with him at least until I find another, more helpful doc.

Hey brother I have all the confidence in the world in you. You’re here asking questions. You changed your own TRT knowing that the medical professional treating you wasn’t entirely correct. It take some guys months or years to get to that point. Me included. Not sure what you thought was my lack of confidence, but I assure you I did not intend it.

My only goal here is to figure out where you’re supposed to be according to your endo’s schedule. I doubt this is his first time, so I’m sure he has some sort of a baseline. If you pop up off the charts he’s going to know something is up.

It takes a few weeks to reach peak blood serum levels with injections. That’s why some protocols call for front-loading twice the dosage on the first injection to get to peak levels quicker. I haven’t really read much on going backwards, but I assume the same applies. That’s why I suggested the roidcalc above, so you could input values to try and figure out what dosage to inject to try and have the same MGs in your system that you would on your endo’s protocol.

You still have 12 days, so I would say if you injected none until the 20th, then injected 100mg, you probably wouldn’t be too far off from where you’re supposed to be. The math is complicated.

Maybe KSman could help out.

That should be OK.

Well did the “Peak” test today. Will update when I get the results.

Endo asked for T, PSA, and CBC tests. I had him add the E2 test as well.

We’ll see…

Posted results in “Pinion - New Updated Labs”