Testosterone is a hormone made by the testicles. It is important for a man's sex drive and physical appearance.
Certain health conditions, medicines, or injury can lead to low testosterone (low-T). Testosterone level also naturally drops with age. Low testosterone can affect sex drive, mood, and changes in muscle and fat.
Treatment with testosterone therapy may help reduce symptoms.
How Testosterone Affects Health
Testosterone makes a man look and feel like a man. In a man, this hormone helps:
- Keep bones and muscles strong
- Determine hair growth and where fat is on the body
- Make sperm
- Maintain sex drive and erections
- Make red blood cells
- Boost energy and mood
Causes of Low Testosterone
Beginning around age 30 to 40, testosterone levels may start to slowly decrease. This occurs naturally.
Other causes of low testosterone include:
Some men with low testosterone do not have any symptoms. Others may have:
- Low sex drive
- Problems having an erection
- Low sperm count
- Sleep problems such as insomnia
- Decrease in muscle size and strength
- Bone loss
- Increase in body fat
- Trouble concentrating
Some symptoms may be a normal part of aging. For example, it is normal to feel less interested in sex as you get older. But, it is not usually normal to have no interest in sex.
Symptoms may also be caused by other conditions, such as high blood pressure. If any of these symptoms are bothering you, talk with your health care provider.
Your provider will likely have you get a blood test to check your testosterone level. You will also be checked for other causes of your symptoms. These include medicine side effects, thyroid problems, or depression.
If you have low testosterone, hormone therapy may help. The medicine used is man-made testosterone. This treatment is called testosterone replacement therapy, or TRT. TRT can be given as a gel, patch, injection, or implant.
TRT may relieve or improve symptoms in some men. It may help keep bones and muscles strong. TRT seems to be more effective in young men with very low testosterone levels. But it is unclear whether TRT is helpful for older men.
TRT has risks. These may include:
At this time, it is unclear whether TRT increases the risk of heart attack, stroke, or prostate cancer.
Talk with your provider about whether TRT is right for you.
If you decide to start TRT, be sure to see your provider for regular checkups.
When to Call the Doctor
Call your provider if:
- You have symptoms of low testosterone
- You have questions or concerns about treatment
Male menopause; Andropause; Testosterone deficiency; Low-T; Androgen deficiency of the aging male; Late-onset hypogonadism
Allan CA, McLachlin RI. Androgen deficiency disorders. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 139.
Morgentaler A, Zitzmann M, Traish AM, et al. Fundamental concepts regarding testosterone deficiency and treatment: international expert consensus resolutions. Mayo Clin Proc. 2016;91(7):881-896. PMID: 27313122 www.ncbi.nlm.nih.gov/pubmed/27313122.
US Food and Drug Administration. FDA Drug Safety Communication: FDA cautions about using testosterone products for low testosterone due to aging; requires labeling change to inform of possible increased risk of heart attack and stroke with use. www.fda.gov/drugs/drugsafety/ucm436259.htm. Updated January 16, 2016. Accessed June 27, 2017.
Review Date 5/7/2017
Updated by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.