T Nation

Blood Work After Injection


After an injection of testosterone cypionate how many days should you wait to get blood work done? I’ve read that test cypionate peaks around the 2nd or 3rd day after injection. Should blood work be don’t at peak times or after?


I inject once a week. I do my tests on the morning of my next inject, BEFORE my injection that day.

I’m sure others will chime in that are far more experienced with this.


It depends on how often you’re injecting and if you want to capture a peak or valley if they exist. As mwhities suggested, test cyp peaks T blood serum levels on average 3 days post injection.

If you’re injecting once per week and test 3 days after the injection, you’ll likely capture your peak level. If you test the day prior to your next injection, you’ll capture your lowest level, since you’ll be injecting and increasing your T levels the next day.

If you inject twice per week or EOD, there will be very little peaks/valleys. I inject EOD and typically get my blood work done on days I’m not injecting.


Thank you for the feed back. I was told my some people to do lab work 3 days after injection and some people say it should be done the day before the next injection so I was a bit confused. I’m 37 and just started TRT a few months ago and initially my Dr started me on 100mg of test cypionate every 2 weeks than changed it to 100mg every week since my numbers were still low (don’t have lab numbers with me at the moment). 1month later he he scheduled me to have blood work done 3 days after my injection. Numbers came back high(again, I don’t have the lab numbers with me) and changed the protocol to 100mg every 10 days. My last injection was on 11/5/16 and I will getting lab work done today 11/11/16 which is 6 days after injection. I have a feeling it will be low.


Please read all of these, but see bold for specifics to your question.

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Best to inject twice a week and always do injections halfway between to avoid introducing changes to lab values that are timing artifacts.

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