SHBG won’t modify the half life of the ester itself, but it does have a mechanism to control uptake of testosterone in the body which is not fully understood. Much about SHBG remains unknown and many people really don’t give SHBG the credit and respect that it deserves. It does so much more than bind up testosterone making it “useless” (the thinking that bound T is useless is also not true).
Here is one recent study that I found quick. Skip to the conclusion:
Sex Hormone Binding Globulin Modifies Testosterone Action and Metabolism in Prostate Cancer Cells
SHBG has been used as one measure for injection protocol frequency for myself and others for many years. It is why those who are low are frequently doing daily injections. It is discussed elsewhere here as SHBG has been just about beat to death in older posts.
See, I just switched to prop after being on cyp for 2+ years with no real effect it was an option given by Defy after lab results being meh on 40~mg test cyp eod and a SHBG of 12. This is not the kind of information I was expecting to see about switching to prop.You are correct. SHBG most certainly does affect the rate at which testosterone metsbolizes and leaves the body. I can’t even recall the rationale for trying Propionate / it was such a bad idea.
We have to inject daily with Cypionate or Enanthate because it metabolizes faster than the 3/4 day half life, so apply that same logic to Propionate which has a half life of 24 hours. I would inject at 8am and by 2pm be hypogonadal. Like I said, it was great at first. It took a while (maybe 6-8 weeks to notice this) but even my wife got scared from seeing the changes in me and wanted to know what was wrong.
I don’t have the exact lab results at hand right now but >1500 TT in the am, 600-650ish in the pm.
40ish FT in the am and dropping to mid teens in the pm. Very large rollercoaster / repeat that daily.
Just stick with the longer esters. If Cypionate/Enanthate aren’t working then try supplementing with a scrotal cream.