T Nation

How Long Does It Take for Test Levels to Drop?

If you are on Testosterone injections via test cyp
And you have a Total test level of 2500ng dL, if you stopped the injections how many days would it take to get back down to 1500ng dL ?

It’s not a linear relationship, but it takes 5 weeks for the Cyp to clear your system, so I’d guess 3-5 weeks for your TT to drop in half

It’s not a linear relationship,
I haven’t heard that before, does that mean it’s different for each individual person ??

It means that lowering your dose 50% doesn’t mean your TT will be 50% lower too.

So stopping your test completely, all that injected T takes 5 weeks to clear your body, but doesn’t mean it’ll take 5 weeks for your TT to come down, or that it’ll come down to a certain number.

In theory if test has a first order kinetic (most drugs have that but don’t know about test, with extreme dosages there’s often the problem of enzyme satiation which changes kinetics too) it takes one half life to cut the plasma concentration in half. For T cyp that would be 8 days (didn’t confirm that via papers) so let’s say in 9 days you’re back to 1500 ng/dL. That’s the oversimplified theory.

This is the first time I’ve heard that. I assumed it would be much longer given the HL. Interesting

I might just have to go and get a blood test and not have to guess it!

Is this a “Hey captain obvious” or serious comment? Hard to differentiate that statement haha

1 Like

Haha no I’m being genuine. It’s tough to read online lol.

Since I plan on B&C and hopefully slipping it by my clinics labwork/check ups, I’m very interested in how long it would take to clear the higher T out before doing bloodwork for them. If I go too high they’ll lower my dose

7-10 day halflife. Then 7-10 halflife etc. it is a curve really. Thats doe Test E and C. Prop is like 3 days.

I plotted it here.

This is how it looks every time you stop T Cyp cold turkey. The levels fall in an exponential curve. You can see I marked the day where the levels are cut in half, here it’s 6 days. So if you know your plasma concentration you can relatively exactly calculate where you’ll be on day x. You just have to use the formula:

You should then start injecting in your TRT manner again when the levels have reached trough concentration. Then you’ll be back to your TRT. Granted this only works if you don’t take drugs like EQ with your blast which has a longer HL.


Yeah I believe you bro,
Didn’t think you were being sarcastic,
I was thinking to get a test though, but come to think of it that won’t work as I’m looking to start back injecting tomorrow, I’m pretty intune with my body and I would say the past day or 2 I’m definitely coming down, I think I’m around the 1500ng mark and it’s been 8 days since I stopped I think,
So sounds about right lol


This is interesting did you see you put in the box your taking 1000mg test per week,

That was just an example. It looks the same with 250, 2500, 5000 just the numbers would be higher but it takes the same amount of time to get to half the concentration. That’s the part that I wanted to emphasize.

1 Like

Ok perfect thanks for that bro !
I’ll get back injecting tomorrow

Sorry I was trying to reply to the other guy on the thread. Looks like you got plenty of useful info here tho

Nah I’m sticking to test, anavar & mast these days

@lordgains is that some sort of calculator/app? or is that just a spreadsheet plotting the given function over time?

steroidplotter .com