It's called Androgen receptor sensitivity. Some men can't tolerate a lot and they can make a little bit go long ways and others take a lot to go a little ways. It's as simple as finding the dose that improves the symptoms of the deficiency while avoiding any unwanted side effects. It's not aiming for any specific level and men or so caught up in numbers that they just can't understand that simple fact. If a level of 700 improve symptoms then that's the number and if the level is 1500 to resolve symptoms that's the number. But whatever number it is it has to be balanced against any unwanted side effects. No one should have to add any additional chemical or drug to control side effects no different then we didn't need to take any chemicals or drugs when we were teenagers or in our 20s when we had excellent testosterone levels. And the receptor saturation is not a theory it's proven in the medical literature, and in medical physiology. People just want to ignore physiology, but this receptor saturation is fully understood. The one thing that we haven't found, though is the saturation point in muscle tissue that's why bodybuilders are as big as they are.