Free Testosterone Range
Hildegard Mccauley
The test described in this article measures the total amount of testosterone in the blood. Much of the testosterone in the blood is bound to a protein called sex hormone binding globulin (SHBG). Another blood test can measure the "free" testosterone. However, this type of test is often not very accurate.
In females, the ovaries produce most of the testosterone. The adrenal glands can also produce too much of other androgens that are converted to testosterone. Levels are most often checked to evaluate signs of higher testosterone levels, such as:
The examples above are common measurements for results for these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.
Certain health conditions, medicines, or injury can lead to low testosterone. The testosterone level also naturally drops with age. Low testosterone can affect sex drive, mood, and muscle mass in men.
Reviewed by: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Testosterone is considered to be the "male hormone" that's produced in men by the testes. Although women's ovaries produce some testosterone, the hormone is produced in much higher concentrations in men and it is responsible for many of the secondary sex characteristics seen in men such as a deeper voice and hair on the chest, in addition to contributing to a healthy libido, building muscle mass, and maintaining energy levels.
The problems associated with high testosterone levels are infrequent and rare in middle-aged and elderly men who are not receiving testosterone or other steroid treatments. When the testosterone level becomes out of balance, it usually becomes too low rather than too elevated.
The most common "out of balance" testosterone levels are found to be on the low side of normal; this occurs because a male's highest testosterone level usually peaks at about age 20, and then it decreases slowly with age. It has been suggested that a 1% decrease in testosterone level per year is not unusual for middle-aged (30 to 50 years old) and older males. While this decrease may not be noticeable in some men, others may experience significant changes starting in their middle-aged years or more commonly at age 60 and above. This drop in testosterone levels is sometimes termed hypogonadism, "male menopause" or andropause.
In general, the normal range in males is about 270-1070 ng/dL with an average level of 679 ng/dL. A normal male testosterone level peaks at about age 20, and then it slowly declines. Testosterone levels above or below the normal range are considered by many to be out of balance. Moreover, some researchers suggest that the healthiest men have testosterone levels between 400-600 ng/dL.
Both men and women who utilize anabolic steroids to gain an athletic "edge" (for example, some professional athletes) or to increase muscle mass (for example, some bodybuilders) may experience high levels of testosterone and develop complications, and side effects, for example...
So, how does one ensure that testosterone levels remain in balance? Some doctors suggest that monitoring testosterone levels every five years, starting at age 35, is a reasonable strategy to follow. If the testosterone level falls too low or if the individual has the signs and symptoms of low testosterone levels described above, testosterone therapy can be considered. However, once testosterone therapy is initiated, testosterone levels should be closely monitored to make sure that the testosterone level does not become too high, as this may cause stress on the individual, and high testosterone levels may result in some of the negative problems (described previously) seen.
Finding the appropriate balance of testosterone is possible through discussions with your doctor, and it requires your willingness to have testosterone levels checked before the initiation of therapy and then checked routinely in the future.
Dr. Marina Basina is an ABMS board certified endocrinologist specializing in diabetes mellitus type 1 and 2, diabetes technology, thyroid nodules, and thyroid cancer. She is currently a clinical associate professor at Stanford University School of Medicine and is a medical director of inpatient diabetes at Stanford Hospital.
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Testosterone is a hormone known as an androgen. Although people know it primarily as a male sex hormone, females also need certain levels of testosterone. In females, most testosterone converts into the sex hormone estradiol.
Because hormone levels change rapidly during puberty and development can occur at different ages for different people, the Tanner scale is a more accurate way to judge changes during puberty than using age.
Hormone levels change for people of all sexes as they age. Females experience a more dramatic change in hormones, with levels falling until they reach menopause, while males experience a more gradual change in hormone levels.
High testosterone levels are unusual in adult males, while children with high testosterone levels may have a growth spurt or start puberty early. High testosterone in all sexes can cause infertility, obesity, and in some cases, metabolic disorders.
The total testosterone level test is a blood test. The best time to have the test is in the morning when testosterone levels in the blood are usually highest. However, these levels vary throughout the day, so some people may need a retest to confirm the result.
It is possible to treat males for low testosterone levels with an injection or prescription gel. People using this treatment over the long term could experience potentially severe side effects, such as an increased risk of heart problems.
A healthy testosterone level will vary between people based on factors such as age and sex. If people are not experiencing problems with puberty, growth, development, fertility issues, or metabolic disorders, they will likely have a suitable level of testosterone.
During male puberty, testosterone causes body hair, muscle growth, and a deepening voice. In adult life, it controls sex drive, maintains muscle mass, and helps make sperm. In females, testosterone is important for the growth of bones and muscles, and healthy organs.
There are different forms of testosterone in your blood that may be measured to help diagnose certain health problems. Most of your testosterone is attached to proteins. The proteins prevent your tissues from using the testosterone right away, which helps control the amount of "active" testosterone in your body. Testosterone that's not attached to proteins is called free testosterone. Free testosterone acts on your tissues.
For males who have gone through puberty, the test is mostly used for symptoms of low T levels (testosterone levels which are too low). Testosterone levels tend to decrease with age. But other health issues may also cause low T, such as thyroid problems, long-lasting illness, or problems with the testicles.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Your test results may mean different things depending on which test was done, your age, your symptoms, the results of other tests, and other conditions you may have. So, it's best ask your provider to explain your test results.
If your results are not normal, it doesn't always mean you have a medical condition that needs treatment. It's normal for testosterone levels to decrease with age. And certain medicines can affect your results. If you have questions about your results, talk to your health care provider.
At-home test kits for checking your testosterone levels are available without a prescription. The kits provide everything you need to collect a blood or saliva (spit) sample to send to a lab for testing. Talk with your provider if you think you need to be tested. If you do a home test, share the results with your provider.
Dr. Angelica Balingit is an ABMS board certified internal medicine physician. She has vast experience in treating adult conditions in the hospital, outpatient clinic, assisted living facility, home, and via telemedicine. Her special interests include hypertension, diabetes, arthritis, and anemia.
Ann Pietrangelo is freelance writer and health reporter with bylines on a variety of consumer health publications and leading health information websites. Through her books No More Secs! Living, Laughing & Loving Despite Multiple Sclerosis and Catch That Look: Living, Laughing & Loving Despite Triple-Negative Breast Cancer, she shares her experiences in the hope that others will feel less alone in their health struggles. Learn more at her website.