Published: February 20, 2023 | Updated: June 6, 2024

Testosterone is a hormone produced by testicles in people assigned male at birth. Testosterone can affect many aspects of life, including appearance, sexual development and sex drive (libido). It also helps build bone and muscle mass. A small amount of testosterone is also produced in people assigned female at birth, however this article focuses on low testosterone in males.

Although low testosterone can affect anyone with testicles at any age, low testosterone is more common as people age. It’s important to know that it is natural for testosterone production typically to decrease with age. The Endocrine Society considers low blood testosterone to be a morning level of less than 300 nanograms per deciliter in adults. Testosterone levels vary throughout the day, so testing these levels at 8 a.m. is very important.

“The symptoms of low testosterone, also known as ‘low T’ or male hypogonadism, vary based on age and other factors,” said Lisal J. Folsom, M.D., adult and pediatric endocrinologist with Norton Community Medical Associates – Endocrinology and Norton Children’s Endocrinology, affiliated with University of Louisville School of Medicine. “Sometimes when people have symptoms that may signal low testosterone, testing shows normal testosterone levels. That suggests the symptoms are related to something else entirely.”

8 symptoms that might be related to low testosterone

1. Low sex drive: While a decline in sex drive is typical as we age, people with low testosterone are more likely to experience a drop in libido.
2. Hot flashes: This symptom can range from a sudden sensation of warmth to heavy sweating, flushing or night sweats.
3. Decreased muscle mass: Since testosterone is key to building muscle, low levels may affect muscle mass, but not necessarily strength or function.
4. Breast enlargement: If there is an imbalance between testosterone and estrogen, a person may develop gynecomastia (enlarged breast tissue).
5. Hair loss: Low testosterone can cause loss or thinning of body hair, especially in the armpit, chest, back or pubic areas.
6. Mood and memory changes: Testosterone influences many of the body’s mental processes. Low testosterone may contribute to mood changes, difficulty with memory or decreased mental capacity.
7. Erectile dysfunction: Testosterone contributes to erectile function; a person with low testosterone may have trouble having or maintaining an erection.
8. Fatigue: Extreme fatigue, decreased endurance and a decline in overall energy despite getting plenty of sleep can be a sign of low testosterone.

How is low testosterone treated?

“Testosterone replacement therapy is considered when testosterone is truly low,” Dr. Folsom said. “Before beginning treatment it’s very important to have a thorough evaluation, as many symptoms of low testosterone can overlap with other causes, and treatment with any medication can have risks as well as benefits.”

If your health care provider recommends testosterone replacement therapy, there are several treatment options, including:

• Topical gel applied onto the skin daily
• Patches applied onto the skin daily
• Buccal tablets absorbed through the gums or inner cheeks
• Oral pills swallowed twice daily
• Injections given under the skin or into the muscle every one to two weeks
• Implanted pellets that gradually release testosterone into the body