T Nation

Transdermal Users: Timing w/ Blood Draw?


I have been given conflicting information about timing of product application on days when blood will be drawn.

My common sense tells me that if my blood draw is scheduled for 8am and I apply the gel immediately (within an hour) prior then the spike from the application will skew the readings. With this in mind, I applied daily (mornings) but waited until after I had the blood draw to apply for that day. Doing this, my levels either raised slightly or went down.

I mentioned this to my MD and was told to apply at same time and "not to worry" about the spikes as "this is a true reading".

How do you do it?


I already told you - applied same time everyday regardless of when a blood test will be taken.

What signficant effect do you think there will be? And product information tells you to apply at the same time everyday. And so do doctors.

Thanks for listening.


T spikes then drops rather fast with transdermals. This makes lab results highly a result of lab timing and thus rather suspect. I do not know how this is best managed. FT will be all over the map. TT will be a better indicator. If tested in the AM before T application, 'baseline' TT will be a consistent measure, but I do not know how useful that really is.


I only apply it at night and still test between 700 to 1000 no matter what time of day.


I applied consistently at 7 am every day. Time of blood draw vs last application was 24.5 hours and my numbers decreased from the last reading a month prior.