T Nation

Can Anyone Explain This

When I look at the graphs indicating the pharmacokinetics of various injections there appears to be very little difference in the speed at which the drug provides peak blood levels even though the esthers and half lives are radically different. An example is Test Cyp peaks at approx 1 day after injection then falls to approx 50% of peak level 6 days after injection and levels off at about 20% of the peak level by day 11. Test Prop peaks around day 1 as well which seems odd since I’m under the impression I would feel the effects of Prop much faster than Cyp or Enan so I would have expected the Cyp to peak much later in comparison to Prop. The Prop drops to 50% of peak levels by day 2-3 and half again by a little after day 4. These rates of disipation make sense when compared to the half lifes I find at roidcalc.com but it’s the speed peak blood levels are achieved compared to what I am lead to believe would be the time necessary to feel and see results that is throwing me off.

It is correct in that cyp peaks quickly after being injected. What you have to remember though is while it peaks at the same time as prop, cyp’s peak is much less test than prop’s peak. Cyp makes up for it in that it’s peak lasts longer. That’s why it seems to take longer to kick in, because you have less of it in your system at any given time and not because it just takes a while to activate. Hope that made sense.

I really appreciate the response please at the risk of coming off as anal please allow me to nit pik.

“cyp’s peak is much less than prop’s peak”. Prop contains 83 mg after accounting for the esther while cyp contains 70mg per 100mg. Not a huge difference but the amout of the drug should not be regulating how quickly the drug is effective. Shouldn’t the speed it is effective be based solely on the length of the esther not the size of the dose? Secondly, I’m really talking about why the peaks are at approx the same time but the effects are not.

“cyp makes up for it in that its’ peak lasts longer”. this is true due to the longer half life but you administer prop at higher frequency thus negating that advantage. Again this does not address why if blood levels peak at same time benefits are considerably later down the road with the cyp.

“it (cyp) seems to take longer because you have less of it in your system at any given time” (assuming same dose). If this were the reason then if I frontloaded cyp by 20% (since it has approx 20% less test due to the weight of the esther) then it would be felt just as quickly as prop, which I don’t believe would happen. Again this does not actually adress why in spite of blood levels peaking at same speed one is not felt for some time after the other.

I can understand why I might feel it on the back end longer with cyp due to the half life difference provided by the esther but it still makes no sense to me on the front end when I see the blood level peaking at roughly the same time post injection.

Any other theories or input from you vets would be appreciated. I’m trying to get smart enough to try running a first cylcle by you guys.

Where the hell have all the usual suspects gone BBB, juice20, mk, p22, etc.

That is exactly the reason you want to frontload any long acting esters.

I want to stress one thing about frontloading testosterone. If you frontload say 1000-1500mg, not only does your testosterone plasma level skyrocket so, too, does your estrogen levels. Testosterone levels descend much more rapidly than do your estrogen levels, that is why I recommend that if you ARE going to frontload a test enan or cyp that you take an anti-aromatase inhibitor (femara, arimidex) at least for the first couple of weeks so you can keep your estrogen levels at bay.

Yes, having estrogen present during a cycle DOES increase gains, it also does a number on your HPTA and the rock hard chiseled physique you are undoubtedly searching for.

I would recommend nolvadex, however, recently I have researched it a bit more and found out that it does lower IGF-1 levels quite a bit. Not that you can’t grow on nolvadex if you’re taking a gram of test, but, it’s something to consider.

This may be a bit off topic but I am never taking Deca again. I am still trying to get my HPTA back from a cycle FOUR months ago. Hell, I took 250mg of clomid/day for a week and I still felt like I had no natural test production going on…

Hey, if you can’t recover, dust yourself off and do another cycle! :wink:

Hope that helped…

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[quote]bushidobadboy wrote:
I need to look more closely at this, but my (possibly flawed) understanding is this:

The speed at which the compound enters the bloodstream is not affected by ester length, ie any oil based test (prop, cyp etc) will leave the IM site and enter the bloodstream just as quickly as any other, HOWEVER, the circulating test cannot exert its effect until all the ester has been completely removed and this obviously varies in time from ester to ester. Hence the reason that the effect of prop is felt much quicker than cyp, and the reson that cyp takes a LOT longer to be ‘used up’ and exit the body.

Think about it - if you inject 3ml of cyp into your glute, you don’t have a pocket of fluid in there for any longer than if you had shot prop…

As I say though, I could be wrong on this, but I thought I would offer my opinion…


Bingo BB, reckon that’s spot on! Bigger differences in dissipation may occur if the shot was water-based as this would have a lower viscosity than an oil, but even then it’s unlikely peak blood levels wouldn’t differ by that much.

Muscles are full of blood vessels and capillaries, hence it quickly entering the blood stream. May be a larger difference with sub q injections!

JMO :wink:

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BBB, you da man. So basically they will have essentially the same amount of speed at which they are in the blood stream but the substance is not active until the body burns off the esther which will provide in a big difference in time based on which ester is in it. The reference you included is invaluable because it shows us how long it takes for various esters to release and the substance to become active rather than just their half lives like we usually see.

Thanks again to all.

Simply think of it this way: At the time that there is the most drug in your body, this is the time when more of the drug is going to release into the blood stream. As the the amount decreases, so does the rate that it releases.