Testosterone is a sex hormone often associated with males, though females have small amounts. If a male has a low level of testosterone, the symptoms can include erectile dysfunction, and reduced bone mass and sex drive.
The hormone has many important functions, including:
The development of the bones and muscles
The deepening of the voice, hair growth, and other factors related to appearance
The production of sperm
Testosterone production can slow as a person ages, and many older men have symptoms of low testosterone.
The American Urology Association define low testosterone as less than 300 nanograms (ng) of the hormone per deciliter (dl) of blood. They also reported that about 2 in every 100 men have low testosterone.
1. Problems with erections
Low testosterone can make it difficult to get or maintain erections.
Testosterone stimulates the penile tissues to produce nitric oxide, which starts several reactions that result in an erection.
If levels of the hormone are too low, a man may not be able to get an erection.
2. Hair loss
Many men experience hair loss as a natural part of aging, and age-related hair loss can also affect women.
Authors of a study from 2012 found that testosterone implants supported the regrowth of hair in some women who were receiving treatment for symptoms of sex hormone deficiency.
3. Reduced bone mass
Testosterone helps to produce bone tissue and maintain bone volume.
Low testosterone can lead to a reduction in this volume, which can make the bones more susceptible to fractures.
4. Reduction in testicle size
A male with low testosterone may notice a reduction in the size of their testicles that is not related to cold temperatures.
The scrotum may also feel softer than usual.
5. Reduction in the amount of semen
Semen is the fluid that makes up the majority of male ejaculate. This type of fluid helps the sperm move toward the egg.
Testosterone helps stimulate the production of semen, and reduced levels of semen can indicate a reduction in testosterone. It can also lead to trouble with fertility.
6. Difficulty sleeping
Men with low testosterone may find it difficult to fall or stay asleep.
Many males with low testosterone also have sleep apnea. This potentially severe disorder causes a person to temporarily stop breathing, which can disrupt sleep
The following are other factors that can cause erectile dysfunction:
Stress or anxiety
High blood pressure
When to see a doctor
Low testosterone does not always present symptoms, and some people only learn about it after a routine physical examination with bloodwork.
However, anyone who experiences one or more of the symptoms listed above should seek medical attention.
To diagnose low testosterone, a doctor will often perform a physical evaluation and review the person's symptoms. The doctor may also request testing to look for additional signs.
For example, a bone density test can show diminished bone mass, one result of low testosterone.