Is it not the adrenal glands? I visited a Nutritional Doctor, and she said that the adrenals released all the major growth hormones.
If you were to get your adrenal glands in optimal condition, wouldn't this be benefical for muscle growth? Almost like taking PH's only you are cleaning up your bodies REAL natural ability to release it all?
Sorry this may sound like a stupid question. But I am new to the PHs