"After age 30, most men begin to experience a gradual decline in testosterone," states David Samadi, MD, chairman of the urology department at Lenox Hill Hospital in New York City.
Though testosterone levels never reach zero (as estrogen levels do in women during menopause), low testosterone levels men to experience symptoms such as fatigue, low libido, and loss of muscle mass.
While reduced testosterone is more common in older men, it can occur in younger guys as well. Luckily, all the causes of low testosterone in young guys are curable, so if you encounter these symptoms at any age, there's no reason to dismiss it.
For younger men, a fall in testosterone levels can be caused by some ailments, such as type 2 diabetes, chronic liver or liver disease, COPD or other lung disease, or pituitary gland issues, according to Dr. Samadi.
Genetic causes of low testosterone in men include the ailments Klinefelter syndrome, Kallmann syndrome, Prader-Willi syndrome, and Myotonic dystrophy. Another disorder that could result in low testosterone is hemochromatosis, which makes the body store too much iron.
"Low testosterone can also result when something happens, like trauma or steroid use, that prevents the testes from making the hormone," states Bruce Gilbert, MD, PhD, an adjunct clinical professor of urology and reproductive medicine at Weill Cornell Medical College and director of reproductive and sexual medicine at the Smith Institute for Urology of their North Shore-LIJ Health System.
Additional causes of low testosterone in men younger than 50 include pituitary gland tumors, HIV disease, and radiation therapy or chemotherapy for cancer.
Doctors categorize causes of low testosterone as primary or secondary.
"Primary hypogonadism stems from a problem in the testicles," Samadi states. "This could be from a developmental issue, injury to the testicles, or radiation or chemotherapy treatment.
Can It Be Low Testosterone?
Irrespective of the cause, low testosterone symptoms are the same.
"Symptoms include low libido, erectile dysfunction, fatigue, decreased mental acuity, and moodiness," Dr. Gilbert says.
"Younger men with low testosterone usually come to me and say, 'I can't work out like I used to, and I've lost interest in sex.' â€
If you suspect low testosterone, the first step is to see your primary care physician.
If your blood test reveals low testosterone (usually defined as a level lower than 300 ng/dL), the doctor may treat you or refer you to a specialist, such as an urologist or endocrinologist.
Not everyone with low testosterone needs treatment. "When it comes to treating low testosterone in younger men, we usually reserve treatment for those who have symptoms, such as fatigue and low libido," Gilbert says.
In men who don't make the hormone in their testes because of a condition such as Klinefelter syndrome, or those who have lost their testes because of cancer, the only option is testosterone replacement therapy.
In these circumstances,"therapies are often used just in the brief term, and if a physician has close monitoring and understanding of the individual," Gilbert says.
An important consideration for younger men before getting treatment is fertility. "You do not wish to offer supplemental testosterone to men who want to be fertile because it can turn off sperm production," Gilbert says.
Once a young man goes off testosterone supplementation, there's a chance his sperm count will never return to what it was before he started. "Therefore, men of reproductive age should consider alternatives that might increase their testosterone in addition to maintain their semen production," he states. One such alternative is a class of drugs called selective estrogen receptor modulators (SERMs).
Other treatments for low testosterone include weight loss and other lifestyle modifications, like eating healthy and increasing exercise.
The bottom line, though, is that if you've got low testosterone symptoms, then it's important to see your doctor. Then, your doctor can rule out potentially more significant causes of your symptoms, including high blood pressure or a thyroid problem, and offer treatment that can enhance your power and quality of life.