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I came across this on reddit - someone has correlated different test doses & total test blood levels. It’s Interesting to analyse… I’m wondering if anyone knows of any other studies/data/links to similar such things?
Thanks!
There are a few testosterone studies in which dose is listed, and they have TT, FT, E2 listed with average and standard deviation. It gives you an idea.
Most of the studies I have seen use once weekly injections, and measure at the trough. Someone on ED, EOD or even 2X a week will have lower peaks and higher troughs than if they were doing once a week. If measuring at trough, they will on average read higher.
Can you please post the link to the internet source? I’d love to get my hands on the original paper too. It looks like an experiment with multiple subjects. I’d like to read the full paper. I did a similar experiment on myself. The main difference is that I am an N of 1 and I used Free T rather than Total T as my response variable. Also, I only took the dose up to about 250 mg/week. See the graph below.
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If you can provide any links to any of interest in here that would be great. I have seen some studies but this above is the most interesting I’ve seen with the most data correlated. But there isn’t enough information about when the readings were taken. Etc.
These reports are interesting and reflect what I’ve seen over the years. There are large disparities at dosages where there are more than a couple subjects. This assumes all labs are obtained at troughs with the same injection schedule.
For example, looking at the five data points for 150mg/week dosing, levels ranging for 500 to 1300 are reported. Five subjects taking 250mg/week had levels from 750 to 2200.
You just cannot give a specific dose to a specific patient, and expect to reach a specific level on a blood test.
Agree. Another aspect that needs to be considered is that SHBG levels can differ considerably between individuals and that can affect Total T. SHBG binds and protects T from liver metabolism, so individuals with high SHBG levels (such as myself) tend to respond with higher Total T levels than individuals with normal or low SHBG. That is why I used Free T as a response variable in my experiment.
Good point. Then there are those on the same dose, with very similar total and free testosterone levels, and vastly different SHBG levels. Very interesting, and sometimes challenging.
SHBG is one thing but there’s many. High E2 normally results in High prolactin which also suppresses testosterone. And then you’ve got dietary things like soya products which also suppress to some extent. Of course the results are total T only and not free T, it would have been good to have seen both results for each.
Agree there are multiple factors. Yet another we haven’t discussed is laboratory and laboratory method. I got my data all from LabCorp using the same (direct) method. However, the direct method is limited in that it only has sensitivity to 1500 ng/dL. Anything above that returns a result of >1500. In order to be comparable, all of the tests need to be conducted by the same laboratory with the same LC/MS test method, which does not have an upper end to the sensitivity.
https://journals.physiology.org/doi/pdf/10.1152/ajpendo.2001.281.6.E1172
It is worth noting that they gave these men a drug to suppress natural testosterone production (other than test) IIRC. This is important, because one conclusion I drew before seeing that fact, is that doses lower than natural production will cause shut down. That may be true, or false, but the data here isn’t enough to conclude one way or the other.
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