Testosterone Levels by Age

Testosterone is practically a super power among men, with the ability to control sex drive, regulate sperm production, promote muscle mass, increase energy, and even influence human behavior. With all of the benefits this hormone brings, it’s no wonder that a decrease in testosterone would cause quite a stir. However, according to medical researchers, it is a natural part of aging.

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Adolescence to Early Adulthood

According to the Mayo Clinic, testosterone levels are at their highest during adolescence and early adulthood (Mayo Clinic, 2012). The first physical signs of testosterone, or androgens, in the body are apparent during puberty. A boy’s voice changes, his shoulders broaden, and his facial structure becomes more masculine. But as men get older, their testosterone levels decline about one percent a year after age 30.

Male Female 
Age:T Level (ng/dL):Age:T Level (ng/dL):
0-5 months75-4000-5 months20-80
6 mos.-9 yrs.<7-206 mos.-9 yrs.<7-20
10-11 yrs.<7-13010-11 yrs.<7-44
12-13 yrs.<7-80012-16 yrs.<7-75
14 yrs.<7-1,20017-18 yrs.20-75
15-16 yrs.100-1,20019+ yrs.8-60
17-18 yrs.300-1,200  
19+ yrs.240-950  
Avg. Adult Male270-1,070Avg. Adult Female15-70
30+ yrs.-1% per year  

Worried about your testosterone levels? Learn the warning signs of Low T »

Testosterone and Aging

Although testosterone is often thought of as the “fountain of youth” hormone, naturally declining testosterone levels don’t cause signs and symptoms of aging, according to the Mayo Clinic (Mayo Clinic, 2012). However, they can cause changes in sexual function, including:

  • reduced sexual desire
  • fewer spontaneous erections
  • infertility

Other signs of decreased testosterone levels include changes in sleep patterns, emotional changes, such as low self-confidence or lack of motivation and physical changes, including increased body fat, reduced muscle bulk and strength, and decreased bone density. 

According to Harvard Health Publications, the normal range of testosterone levels in healthy males is between 270 to 1,070 nanograms per deciliter (ng/dL) (Harvard, 2010). Testosterone levels can be measured by a simple blood test, in the saliva or via brain hormones that drive testosterone production. According to Mayo Clinic, it’s important to determine if a low testosterone level is due to normal aging or if it is due to a disease, such as hypogonadism, in which the sex glands produce little or no hormones (Mayo Clinic, 2012).

Testosterone and Women

Testosterone levels affect women as well. However, women create lower levels and are more sensitive to androgens than men. Testosterone levels in women vary, but according to the National Institutes of Health, normal measurements range from 15 to 70 nanograms per deciliter (NIH, 2012).

Excess androgens in a woman’s blood stream can cause obvious physical effects, including infertility, loss of scalp hair, acne, or facial hair. Testosterone deficiency, on the other hand, has less obvious effects on the body. A deficiency of this sort can affect a woman’s sexual desire, satisfaction, and mood, according to World Journal of Urology (Guay & Davis, 2003).

The majority of clinical experience with female testosterone levels has been in postmenopausal women who are experiencing problems with decreased sexual desire. Rather than studying women who have not yet gone through menopause, testosterone levels usually are measured only in women complaining of the physical effects described above (Guay & Davis, 2003).

Other Possibilities

While the symptoms described here are considered a normal part of aging, they could also be signs of several underlying factors, including:

  • a reaction to certain medications
  • thyroid problems
  • depression
  • excessive alcohol use

According to Mayo Clinic, the only way to diagnose a low testosterone level is to visit your doctor for a blood test (Mayo Clinic, 2012). The National Institutes of Health suggest that the best time of day to have a blood sample taken for a testosterone test is between 7 a.m. and 10 a.m. The test may need to be repeated a second time. Abnormal results unrelated to age could indicate cancer of the ovaries or testes, failure of the testicles, early or delayed puberty, or chronic illness (NIH, 2012).