What’s the difference between optimal and normal testosterone levels in men? Answer: Symptoms of low testosterone Yes, you read that correctly. Normal testosterone levels in men can be associated with symptoms of low testosterone. That’s because the so-called normal range for testosterone (and other hormones for that matter) has little to do with health or represent levels associated with lower risk of disease and mortality.
The normal or reference range is based on pure statistical methodology and simply defines where the middle 95% of the men fall with respect to their testosterone level. The bottom 2.5% are considered to be low and the top 2.5% are considered to be high. If your testosterone level falls within the range of the middle 95% of the population you are considered to have “normal” testosterone levels.
“Normal” levels reflect levels in the absence of frank disease. Optimal levels are those required for peak efficiency and function, and prevention of age-related decline.
But, here’s what’s important to recognize. Half the men require testosterone levels in the upper half of the range. Yet, most physicians will only treat men whose testosterone levels fall in the bottom 2.5%. This same statistical methodology once labeled total cholesterol levels up to 260 as normal, and blood sugars up to 125 as normal. We now know that healthy levels for both are much lower.
Normal testosterone levels in men will vary from one laboratory to another. To make it even more confusing there is more than one testosterone to measure. There’s the total testosterone, free testosterone, and bioavailable testosterone. Making it more confusing, testosterone levels are reported sometimes using different units of measure from one lab or study to another (ng/dl, pg/dl, nmoles/l). Most scientific studies report results in terms of total testosterone which is probably the least helpful testosterone level to use for management decisions. See Which Testostereone Level Is The Most Important?
In most labs across the country the reference range for total testosterone ranges from 300 ng/dl to 1,000 ng/dl. That’s a pretty wide spread to define normal testosterone levels in men. A range that wide should raise some questions.
Low Testosterone is a Clinical Diagnosis
Many physicians approach replacement of any hormone from purely a laboratory perspective overlooking the complaints of the patient. Dr. Abraham Morgentaler, a Harvard urologist frequently makes the point, however, that low testosterone or low T is a clinical diagnosis. This means that patient symptoms should be taken into account. A man with several symptoms suggestive of low testosterone should not necessarily be denied treatment because his total testosterone is 350, especially if there isn’t a reasonable alternative explanation to explain his symptoms.
Optimal Testosterone Levels in Men
Like cholesterol and blood sugar we are learning better what healthy testosterone levels really are. Most of the growing evidence in the literature suggests that testosterone levels should be in the upper third of the reference range. We consider that to be optimal levels.
Optimal testostereone levels are those associated with lower risk of disease and better quality of life. A study published in the Journal of the American College of Cardiology found that men ages 69 to 81 with total testosterone levels above 550 ng/dl had a 30% lower risk of cardiovascular disease. Below the level of 550 ng/dl it did not matter what the level was with respect to heart disease. In other words, a male with a total of testosterone of 300 ng/dl has the same risk for heart disease as the man with a level of 549 ng/dl. This study appears to establish a floor of 550 ng/dl for what an optimal total testosteorne level should be at least for cardiac protection (for men ages 69 to 81). It is likely that a higher level is needed for younger men.
These findings are consistent with this study published in Circulation in which men (ages 40 to 79) with total testostereone levels in the top quartile had a 25% to 30% lower risk of all-cause mortality than those with total testosterone levels in the bottom quartile. The Endocrine Society recommends that when treating men for low testosterone that levels be raised into the 400 ng/dl to 700 ng/dl range. Thus, that would justify treating men with symptoms of low T who have levels within the reference range.
What are optimal or normal testosterone levels in men? The answer is not entirely clear, but levels in the upper third of the range are certainly healthier than levels in the lower third of the reference range. I believe some day we will get to the point where we define optimal and normal testosterone levels in men as one and the same.
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