What’s a Low Testosterone Level?
While the signs and symptoms of low testosterone levels can be easy to recognize, making a diagnosis of testosterone deficiency, or low testosterone is a bit more challenging and confusing. This confusion has to with the fact that the reference range used for testosterone is based on statistical methodology rather than science.
The reference range for testosterone (and most medical tests) is determined by measuring testosterone levels in many individuals without regard to whether they have symptoms or not. The mean value for levels is identified and the high end and low end of the reference range is arbitrarily placed at two standard deviations from the mean value.
This means that by solely using the reference range for diagnosing testosterone deficiency that only two and half percent of men can ever be “testosterone deficient”. This is nonsensical since most men over age 60 and many men over 40 or 50 suffer many symptoms associated with low testosterone levels.
The reference range in adult males (regardless of age) for testosterone is 300 ng/dl to 1,000 ng/dl is most laboratories. That’s a wide range. Some men function well and are symptom free at relatively low levels, while some men can be significantly symptomatic with levels in the middle of the range. One thing we know is that testosterone levels decline with age and what is “normal” for one male may not be “normal” for another.
Low testosterone levels should be diagnosed based on a combination of symptoms and testosterone levels. A testosterone level of 400 ng/dl in a 50 year old male with no symptoms is less concerning than a level of 500 ng/dl in a 50 year old male who complains of loss of libido, mood swings, weight gain, and a lack of pep or vigor.
Unfortunately, most physicians tend to rely only on the reference range and will not treat a male unless the testosterone level is below 300 ng/dl.
Cholesterol and blood sugar reference ranges were once based on the 2 standard deviation methods with the upper limit of normal for cholesterol once being 260 mg/dl and the upper limit of normal for blood sugar once being 140 mg/dl. But, based on scientific studies, and as we learned more about the health effects of high cholesterol and blood sugar the upper limits have been adjusted so that the upper limit is now 200 mg/dl for cholesterol and 100 mg/dl for blood sugar. Some day we will see similar refinement in thought with testosterone.
What is an Optimal Testosterone Level?
If we take the same approach in determining low testosterone levels as we did with cholesterol and blood sugar, and look at medical studies, we find that men who have testosterone levels in the upper third of the reference range suffer less heart disease, less cancer, and less all cause mortality than men in the lower third of the reference range.
Based on this it would seem reasonable that any man experiencing symptoms of low testosterone should consider treatment if he has symptoms and a testosterone level below approximately 700 ng/dl or the upper third of the reference range.
What Are the Sign/Symptoms of Low Testosterone Levels?
- Decreased libido and sexual performance
- Decreased lean body mass and muscle strength
- Increased body fat
- Decreased glucose metabolism (high blood sugar)
- Increased total and LDL cholesterol
- Decreased wound and tissue healing
- Decreased memory and cognition
- Increased risk of heart disease
- Increased risk of Alzheimer’s disease
- Decreased bone density
- Increased risk of elevated blood pressure
- Increased risk of depression
- Decreased skin tone
- Increased risk of tendon and joint degeneration
- Decreased stamina, energy, and well-being
Do I Have Low Testosterone Levels?
If you are experiencing even just a couple of the signs and symptoms above you should have your testosterone levels measured and be evaluated to rule out other causes. If there is any question whether your symptoms might be related to low testosterone it is reasonable to consider a trial of testosterone replacement for 3 to 6 months to see if your symptoms improve. Low testosterone levels can be effectively treated.
See related articles, “Low Testosterone Symptoms“, “Testosterone Deficiency“, and “Testosterone Therapy“.