this is a highly debatable topic... mainly because the regulations on AAS limit the amount and degrees of research allowed. because of this, there will always be some bro-science, theories, and debates.

you and i can both speculate on the number of receptors in the human body and how much of a given compound they are able to assimilate over a given period. in the end, it's purely speculation. neither of us can definitively say one way or another. which brings me to deductive reasoning...

I think there are enough receptors for your body to handle a whole hell of a lot more than 250mg test and 500mg tren. Probably enough for 2 grams of EACH and still leftover receptors that are unbound.

technically speaking, you're probably right, total receptors may very well be sufficiently present. specifically speaking, however, total receptors can be misleading. not all receptors are created equal. each type of receptor is genetically programed to interact with specific molecules. i like to use the analogy of doors and keys.

the doors would represent the receptor, and the keys would represent the hormone or molecule possessing the affinity to bind. essentially, these doorways remain closed and locked. when a visitor arrives that holds the key, the door is then unlocked, thus allowing passage. if the visitor does not possess the key to this lock, the door remains closed and passage is not permitted. the same is true with hormones, neurotransmitters, etc, and their respective receptors. make sense?

Some other facts:

genetics def play a major role in this. some people genetically have heightened levels of gene expression for synthesizing certain proteins, for example. this means the person possesses greater amounts of that protein, as well as the cells containing it, than their more average counterparts. since receptors are a part of the living cell, possession of more cells equates to more receptors than the next man.

as mentioned previously, receptors are part of the living cells, and one of their roles is to assist in the communication processes provided by the chemical and hormonal systems of the body with the cells. the cells are incapable of producing more receptors within themselves. for additional receptors to become available, additional cells must be produced, either thru hyperplasia or protein synthesis.

the brain communicates with the cells in 3 ways: electrical impulses, neurotransmitters, and hormones. in order for the latter two to be successful, the cells require a means for their respective instructions or messages to be received. this is made possible thru the receptors on the receiving cells. these intricate processes do not simply stop with sending the messenger to deliver the message. both positive and negative feedback responses play roles here; otherwise, the brain wouldn't know when to stop sending messengers.

most everyone here knows and understands negative feedback responses. at least i hope so, since guys like you and i use the terms so much. one way that negative feedback is sent to and received by the brain is when the respective process has completed. another is when the cells are no longer receiving the messages being sent. if the neurotransmitters or hormones are unable to bind to their receptors, and are left in circulation to their given time, the brain is signaled to halt their respective release. it is the cells that send these signals, and they do this in response to occupied receptors.

so, to summarize the facts:

• receptors are part of each living cell
• receptors aide in the body's communication processes by allowing the "messengers" to be received
• receptors are genetically programmed to bind with specific sets of molecules
• the brain recognizes when uptake is not occurring via negative feedback
• genetics play a role in the size and number of cells in the body

Right so how do you know if all receptors are used up and how do you know the body doesn't just synthesize more??

considering these facts, instead of answering with what i believe, i'll make another statement and follow with a question:

since the majority of the body parts we are hoping to affect with AAS are tissues, specifically muscle tissues, we know that these compounds increase transcription rates and stimulate protein synthesis and a much more rapid rate than normal. For this to take place, the hormones bind with the receptors located in the muscle tissues, otherwise, they cannot illicit any sort of response from the cell. when we train hard and the compounds aide the recovery by accelerating it, the outcome is increased muscle density and mass. in a nutshell, more muscle is made; therefore, more cells are now present.

since these hormones must bind with the receptors in the muscles' cells to illicit this response, and are levels are typically extremely elevated during our cycles, at some point these receptors become completely occupied. correct? your question was:

how do you know the body doesn't just synthesize more??

if the body sees excessive hormones present and a halted uptake, which this outcome can be yielded even in the absence of muscle tissue breakdown (training), do you believe that the muscles' cells will simply make more muscle tissue without there being tissue breakdown? that would suggest that gear alone can build muscle and continue to do so as long as we inject increasingly excessive amounts. but we all know that is impossible. training provides the stimulus for growth and repair, the diet provides the raw materials for growth and repair, and hormones accelerate these processes.