it has a sar kadian rhythm. in the morning it's higher. it has to be between 300 to 1,000. going back to what you said. too low is not good for you. that's the metabolic. >> how do you feel if you don't have enough? >> you are running out of energy. you have no battery. >> how do you know if it's safe? >> you can replace it now. if you overshoot and have too much testosterone, you increase the risk of stroke and heart attack. too much is not merrier. you have to be in the normal zone of the urologist. >> you have to tell the doctor. >> the biggest problem is the doctor is not always in the loop. 25% of the men get testosterone replacement. 50% get it treated wrongly by not a urologist. somebody who puts him on it. 25% will get the replacement should actually get it. we have to five times of the prescription we had ten years ago. what should you do. you go to your doctor. over 50 i check everyone's level because of the reasons david mentioned. the risk of obesity and diabetes and heart disease and cholesterol and libido and all with low testosterone. that's where the questio