One of the hardest ACTUAL facts to find when searching through steroid and bodybuilding forums is how testosterone supplementation actually shuts you down. It can be worse than trying to find a needle in a haystack, with a who's who of Bro science "professors" adding their own inaccurate take on things.
So HERE is exactly how Testosterone supplementation (AAS) Shuts you down.
LH = Luteinizing hormone
HPTA = Hypothalamic-Pituitary-Testicular Axis
FSH = Follicle stimulating hormone
GnRH = Gonadotropin releasing hormone
When exogenous Testosterone any type of steroid derivative is used, a cascade of actions take place in this order.
Your Hypothalamus (This is your master gland in your brain) secretes GnRH, that causes your pituitary gland to secrete LH & FSH. The increase in these hormones causes the testes to stimulate the Leydig cells to produce testosterone (by conversion of cholesterol). Testosterone then has the ability to undergo various metabolic processes that will inhibit GnRH, which in turn inhibits the secretion of LH and FSH, and that brings a halt to natural testosterone production. This is referred to as the negative feedback loop. Once testosterone has stopped being produced, it no longer sends this negative signal, and GnRH eventually begins to do its job again.
This is how homeostasis is maintained in the human body.
The whole idea of supplementing with steroids is to override the mechanism for negative feedback. There is a huge misconception that we can take huge amounts of steroids and we do not have to worry about not producing testosterone because we are replacing it with an exogenous source.
The big problem with this is we have is that certain steroids cause this to a greater degree than others. Estrogenic steroids, or steroids referred to as wet bulking steroids, convert to the hormone estrogen in larger doses, and this causes greater suppression than an androgen alone.
"Aromatization mediates testosterone's short-term feedback restraint of 24-hour endogenously driven and acute exogenous gonadotropin-releasing hormone-stimulated luteinizing hormone and follicle-stimulating hormone secretion in young men" "J Clin Endocrinol Metab. 2001 Jun;86(6):2600-6. The increased estrogen sends signals that there is to much conversion, while your Hypothalamus sends signals that too much estrogen is in your system, so the secretion of LH and FSH is halted. The leydig cells stop producing test, until homeostatis is met, and testosterone has a higher ratio to estrogen than it currently has. Using something to stop this conversion like aromasin, arimidex or letrozole can also decrease the amount of shutdown caused, or speed up the recovery process.
Some steroids are not as inhibitory of testosterone production partly because of the fact they do not confer to estrogen, Anavar being one, and it doesn't saturate androgen recepetors as trenbolone would.
Saturation of the Androgen receptor or increased androgen levels in the blood are the main cause of shutdown, and with steroids like trenbolone, the effects last much longer because the metabolites linger in the cell and receptor.
Prolactin, another hormone produced by the pituitary and regulated by the hypothalamus, can also decrease testosterone in men. If elevated, prolactin can lead to side effects on cycle and cause problems with recovery and pct. Suppressing prolactin is a good idea to prevent long lasting problems after a cycle has ended. Steroids that can increase prolactin, mainly 19-nors, such as nandrolone and trenbolone, need to be taken with extra precaution.
Keeping this in mind when starting a cycle and planning a PCT is vital.
I have made it as simple as I can, it does not need to be complicated as many make it seem. Take precaution, research thoroughly and never take a shortcut and you will keep yourself in good health and be able to make the most out of every cycle you run, promote longevity and continue to lead a long and healthy life. Nothing is more important than healthy and safety. Take precautions and aim to achieve.