People often associate the hormone testosterone with masculinity and bodybuilding. However, this essential hormone does everything from supporting energy metabolism to regulating your sex drive. In this article, we’ll examine why testosterone is important, the symptoms of low testosterone, the normal testosterone range and how to measure testosterone levels.
Why We Measure Testosterone Levels
Testosterone is essential for both men and women. If your testosterone levels fall out of the normal range, it can be a sign of a severe medical condition. For men, the most common testosterone-related problem is low testosterone (hypogonadism)1.
We don’t often think about testosterone as an essential hormone for women, but it has the same effects on women as men. Women have much lower testosterone levels (10-20 times lower on average), which is why women generally have a higher voice, less muscle mass and smaller bones. High-testosterone in women can be a sign of polycystic ovary syndrome2 or other disorders.
The Science Behind Testosterone
To understand why testing your testosterone levels is important, it helps to understand the science.
The testes in men and ovaries in women are primarily responsible for synthesizing testosterone. However, the production of testosterone actually starts in your brain.
A part of your brain called the hypothalamus releases a hormone called gonadotropin-releasing hormone (GnRH)3. This hormone acts on your anterior pituitary gland to release another hormone called Luteinizing hormone (LH).
LH signals the release of testosterone from either the testes or ovaries. The adrenal cortex of your kidneys also produces a small about of testosterone.
If your testosterone levels are outside of the normal range for your biological sex, you may have a serious health issue. The problem can be at the level of the hypothalamus, pituitary gland or testes/ovaries.
Total Testosterone and Free Testosterone Levels
There are three ways your body transports testosterone in your blood.
Testosterone can attach to the protein albumin; it can attach to sex hormone binding globulin (SHBG); or it can move unbound (known as free testosterone).
A testosterone level test can examine either free testosterone or total testosterone.
Free testosterone and testosterone bound to albumin are bioavailable, meaning your body can readily use them. Testosterone attached to SHBG cannot be easily used by your body.
Typically, tests examine total testosterone levels but some research shows free testosterone tests may be more accurate.
What Are Signs of Low Testosterone?
Unfortunately, testosterone levels naturally decline by about 1 percent per year after we turn 304. One of the most common symptoms of low testosterone is a sharp decline in sex drive. Other common symptoms include extreme fatigue, lethargy and difficulty maintaining erections in men and dry skin, anxiety and pain during intercourse for women.
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Obesity is one of the most common causes of low testosterone5. Changing lifestyle habits and losing weight may improve testosterone levels.
Here is a complete list of the side effects low testosterone may cause:
- Poor Libido
- Depression and Anxiety
- Trouble Concentrating
- Increased Risk of Osteoporosis
- Hot Flashes
- Increased Body Fat
- Trouble Maintaining Muscle
- Dry Skin
Men may also experience the following symptoms:
- Erectile Dysfunction
- Low Sperm Count
- Hair loss
None of these symptoms by themselves are a sign of low testosterone. However, if you experience multiple of the above symptoms, you may benefit from learning how to test your levels of testosterone
What Are Signs of High Testosterone?
Testosterone is responsible for the secondary sex characteristics in men such as high levels of muscle mass, a deep voice and broad shoulders. High testosterone may also be responsible for male facial features such as a wide jaw and an increased facial height-to-width ratio6.
High testosterone is rare in men. It’s most commonly a result of testosterone replacement therapy or steroid use.
Women who have testosterone levels higher than normal may experience a masculine appearance7. It’s easy to find examples of female athletes who have misused anabolic steroids and have developed a masculine appearance.
Some of the signs of high testosterone levels in men include the following:
- Prostate Swelling
- Decreased Testicular Size
- Decreased Sperm Count
- Increased Breast Size
Women may also experience the following symptoms:
- Deepened Voice
- Thinning Hair
- Facial and Body Hair
- Increased Muscle Mass
- Reduced Breast Size
- Irregular Infertility
- Irregular Menstruation
What Are Normal Levels of Testosterone in Males?
Low testosterone is a common men’s health problem. What’s considered a healthy range of testosterone levels varies slightly between sources. However, somewhere around 270-1070 ng/dL is generally considered the normal range.
The Endocrine Society considers low testosterone to be 263 ng/dL.
According to Mayo Clinic, the average testosterone levels by age are as follows:
Under five months old: 75-400 ng/dL
From 6 months to 9 years: <7-20 ng/dL
From 10-11 years: <7-130 ng/dL
From 12-13 years: <7-800 ng/dL
From 14 years: <7-1,200 ng/dL
From 15-16 years: 100-1,200 ng/dL
From 17-18 years: 300-1,200 ng/dL
19 years to adulthood: 240-950 ng/Dl
Testosterone levels outside of this range may be a sign of a medical issue.
What are Normal Levels of Testosterone in Females?
The average testosterone level for a woman is about 20 times lower than the average testosterone level for a man. The normal range for women is about 8 to 60 ng/dL with an average of about 32.6 ng/dL.
Here’s how a woman’s testosterone levels are expected to change over her lifespan.
Under 5 months: 20-80 ng/dL
From 6 months to 9 years: <7-20 ng/dL
From 10-11 years: <7-44 ng/dL
From 12-16 years: <7-75 ng/dL
From 17-18 years: 20-75 ng/dL
19 years to adulthood: 8-60 ng/dL
How to Test Testosterone Levels in Your Body
Having testosterone levels that fall above or below the normal range can have negative effects on your health.
How do you measure testosterone levels?
There are two options: You can either use a home kit or get tested by your doctor. Home kits use saliva and doctors generally test blood.
How to Test Testosterone: From Your Doctor
Testosterone levels fluctuate throughout the day. They generally peak shortly after waking, so your doctor will likely recommend scheduling the test in the morning. A blood test is the most accurate way to test your testosterone.
Total testosterone tests measure testosterone bound to SHBG, testosterone bound to albumin and free testosterone. If your doctor expects that you may have hypogonadism, he or she will likely recommend a total testosterone test.
Free testosterone tests may be useful for men whose testosterone levels are near 300 ng/dL or for women.
How to Measure Testosterone Levels: Home Kits
Testosterone testing has gotten easier with home kits. There are some obvious advantages of being able to test your testosterone levels at home. First, you don’t have to take book time to see a doctor. Second, most home kits test your testosterone levels through saliva. Testing saliva is easier and significantly less invasive than testing blood.
You still need to mail test results to a lab for analysis. The time it takes to get results can vary from a few days to weeks depending on the company.
How accurate is home testosterone testing?
The American Association of Clinical Endocrinologists still recommends using blood tests for testing hormones. However, research8 suggests that using saliva samples to measure testosterone levels may be as accurate as using tears, urine or sweat.
How to Measure Testosterone Levels with Fingers
Unlike the first two methods that provide precise data, the finger test is more of a fun experiment. Hold your right hand in front of your face and look at your second (index) and fourth (ring) fingers.
It’s been suggested that the ring finger has a higher number of testosterone receptors during fetal development. If your ring finger is significantly longer than your index finger, you may have had higher testosterone levels during development.
A Canadian study at the University of Alberta found that, on average, men have a bigger length difference between their second and fourth finger than women (2D:4D ratio)9. Another study found that the difference in finger length might be a predictor of athletic ability10.
However, it goes without saying that your ring finger length can’t be used as an accurate method for diagnosing low testosterone in adulthood.
When Should You Test Your Testosterone Levels?
Testosterone levels are highest in the morning between 8 a.m. to 11 a.m. Doctors generally recommend that you get your testosterone levels checked in in the morning.
Some research shows that the natural diurnal rhythm of testosterone shrinks with age11. Men over 45 can be tested before 2 p.m. and still receive accurate results12. Women should get their testosterone levels tested in the morning. However, women have small fluctuations in testosterone since their overall testosterone levels are low.
Final Thoughts on How to Measure Testosterone Levels
If you suspect your testosterone levels are low, you can either get tested by a doctor or use a home testosterone kit. Testosterone blood tests administered by a doctor will give the most accurate results. Home kits that measure testosterone levels from saliva are still relatively new. However, research shows that they may be relatively accurate compared to other methods.
If you find your testosterone levels are outside of the normal range, medication or a change in your lifestyle habits can usually restore them to a healthy level. However, you should talk to your doctor immediately to rule out potentially serious health issues.