T Nation

The Negative Feedback Loop


Most people that use any form of anabolic steroids are aware of the negative feedback loop for testosterone, where the body shuts down natural test on account of the hormones (steroids) you have been putting in your body. Well what if I said they may be a way around this. Any aas even oxandrolone a mild anabolic adrogenic steroid to some degree shuts down natural test.

It has been shown that as little as 2.5 mg a day has an effect on the hpta. What if I said that its not the steroids responsible the shut down but a signal from the brain or the over production of gaba from the gaba a receptor in the brain. It has been shown that gaba has a negative effect on testosterone or more precisely the firing of Gonadotropin-Releasing Hormone Neurons. As this study demonstrates:- http://endo.endojournals.org/cgi/content/abstract/endo;145/2/495

For those that are not aware what gaba is its substance that is abundant in the brain responsible the calming effect on the brain or inhibiting over stimulation of the brain alcohol is a gaba a agonist (stimulator) its well known that alcohol lower test levels. Also steroids stimulate gaba production of the gaba a receptor this study on stanozolol (winstrol) shows that.

OK so far we have established that the gaba a receptor is responsible for the chemical interaction in the body to signal your body to stop producing LH the precursor to test when on cycle through the steroids having a stimulatory effect on gaba a receptors in the brain. Are you still with me? OK

So far we have concentrated on the gaba a receptor now I want to concentrate on the gaba b receptor which has the opposite effect on test. The study that follows was done on animals but is interesting it showed that a gaba b agonist or stimulator completely reversed the negative feedback loop of testosterone after testosterone administration.

Still with me ok the drug they used in this study was baclofen which is not freely available to the average bodybuilder. But you might be interested to know that baclofen in a derivative of phenibut a russian supplement used for anxiety which is freely available on any supplement site and is even sold on ebay.

Just to summarise phenibut use while on cycle could prove a very useful supplement. As the study shows a gaba b agonist which phenibut is, reverses the negative feedback loop of test. More research is needed but reversing the negative feedback loop would be very advantageous for those on cycle. inhibition of natural test is the biggest problem with using gear.

Post cycle recovery would be minimal as the body would still be producing lh and therefore test. I would think that an anti estrogen may be needed on cycle though with the abundance of test in the system. But a gaba b agonisty may be something to consider.


Sounds interesting and Phenibut is cheap and easy to get a hold of. I might use some Phenibut while on cycle :wink:


I would be very interested to see how that goes for you


Phenibut sounds very interesting however
there is one bad side effect

Addiction and Withdrawals
Tollerance can be seen in as little as 5 days, and in a span of two weeks the dose needs to be increase by 25-30% of the original dose,so more and more will be needed as time goes on,

And after you stop the withdrawls begin some symptoms include

Sweaty hands
Insomnia (some report not sleeping for up to a week)
Low appetite

However you could slowly taper to reduce withdrawls, wich would be much better than going cold turkey


In the past, I tried 30 grams of phenibut, 1 gram a day, for a month and never experienced any addiction....


My good homey,

I like the way you think. Innovation is awesome. I just want to say one thing though, I just took 20mg of baclofen the other day and it is probably the worst drug imaginable for a bodybuilder. It makes you tired and weak in the most unbelievable way. It is a muscle relaxer after all. I actually can't think of a worse drug for a body builder to take. I have no experience with phenibut though...


clinical studies ranged from 250 to 1500 mg daily intially


Yes I see where your coming from, well theoretically if you were to take baclofen while on cycle the best course of action to counter this would be to take it at night before bed. I no that both phenibut and baclofen both have a long half life. And since there both gaba agonist this would add to the normal gh release at night as gaba stimulates gh which would increase growth further.


Also just to add phenibut is prescribed in russia to increase strength.


Russia is a steaming piece of shit though!

Sorry I couldn't resist. You actually may be on to something here.


In that case, my dose was well within that range, at 1000mg daily.


Is this supplement inhibiting the Gaba A receptors somehow? The reason I ask is because if you take a supplement that only stimulates the Gaba B receptor which then send out peptide hormones that stimulate more LH production which is converted to more testosterone in the blood, won't the body pick up on this excess test. and hence increase the negative feedback via increased activation of Gaba A site?

If you do not block the Gabba A receptor somehow won't the body still send back the message that there is a too much test or LH (or whatever it is stimulated by) in the body, which will then cause the Gabba A site to release it's inhibiting substances which tell the body to stop producing so much LH/Test.

Not sure if that makes sense but hell, I am partially retarded so at least I tried.


Well what the studies show are that steroids are gaba a agonist (stimulators) by the mechanism of the body having to much testosterone in it because of the added test that steroids provide the gaba a receptors are stimulated. This signals the body to stop producing test. Taking a gaba b agonist is evening things out so to speak, as ur gaba a receptors are already being stimulated by the steroids. Or more prescisely the extra test in your system.


I see what your sayin'! But what kind of effects will this have in the system? If you have one part of the body saying "secrete more hormones" and the other part saying "secrete less hormone" they are basically both fighting against one another. I wonder if these is a large stress to these particular systems which may have negative effects once you have ceased to add in the supplemented steroids.

Keep in mind that I am not really basing this on any sufficient knowledge or research. The only thing I can say is that the body has a negative feedback mechanism for a reason and if you have to opposite functions going at the same time that is definatley an abnormal condition for the body to cope with. There really is so much involved in negative feedback loops and it is beyond my knowledge but I do think that your post is very interesting and there could definatley be something to it!