You have low testosterone when your testicles don’t produce enough of this sex hormone. Low testosterone is also called male hypogonadism.
Testosterone isn't the only thing that fuels sex drive and performance. But low testosterone can mean you're more likely to have sexual problems like lack of sex drive and trouble getting an erection (erectile dysfunction).
What are low testosterone levels?
According to the American Urological Association (AUA), you have low testosterone if your level is below 300 ng/dL when you're tested twice on separate occasions. Some doctors, though, think levels below 250 ng/dL should be considered low.
Who has low testosterone?
Those who can get low testosterone as they get older include:
- Cisgender men (those who identify with the sex they were assigned at birth)
- Others assigned male at birth (AMAB)
- Non-binary people (those whose gender identities are neither entirely male nor female)
- Transgender women who aren't on feminizing hormone therapy
It's hard to say exactly how common low testosterone is, as studies use different ranges for what they consider to be low testosterone. But one large review study that looked at research over a 40-year period found that between 2% and 77% of older men had low testosterone, depending on their ages.
Low testosterone is most common in people who are older or who have:
- Type 2 diabetes or other long-lasting health conditions
- Sleep apnea
- HIV or AIDS
What Is Sex Drive (Libido)?
Your sex drive, or libido, is what makes you want to have sex. Many things affect your sex drive, including your physical health, emotional well-being, and your relationship. Sex hormones like testosterone and estrogen also play a big part. Variations in these hormone levels could change how much (or how little) you want to have sex.
Everybody has a different sex drive, and there's no right or wrong amount. Also, your libido can decrease because of many things, including your age, medications you take, and your relationship. For these reasons, defining a "normal" sex drive is next to impossible. Usually, you or your partner will know if your lack of sex drive becomes a problem.
Causes of Low Libido
Researchers haven't determined how testosterone decreases libido. But as you age, it's normal for your testosterone to slowly decline.
Low testosterone doesn't always mean you'll have no sex drive. Some people have a healthy libido even with relatively low testosterone levels. For others, though, their libido may lag even with normal testosterone levels. But numerous studies show that testosterone therapy can improve libido and sex drive in men with low testosterone.
Low testosterone is only one of the causes of low libido. Other things can contribute, including:
Psychological issues. Stress and anxiety from daily life, relationship or family problems, depression, and mental disorders are among the many things that can affect your desire to have sex.
Medical problems. Diseases such as diabetes and conditions such as obesity, high blood pressure, and high cholesterol can harm your libido. So can HIV drugs, some hair-loss remedies, and other medications.
Hormonal causes. Testosterone is the hormone of desire for cisgender men, people assigned male at birth, women, and people assigned female at birth (AFAB). Low testosterone could mean low sexual desire. Other hormones can play a role in low libido, too, such as low levels of thyroid hormone or, rarely, high levels of prolactin, a hormone produced in a gland at the base of the brain.
Low dopamine levels. Sexual desire involves your brain, and the brain's chemical messaging system is intimately linked to sexual desire. One of those messengers is dopamine. Doctors have found that Parkinson's disease patients treated with dopamine-stimulating drugs have increased sexual desire.
Low Testosterone and Erectile Dysfunction
Erection problems are usually caused by atherosclerosis, or hardening of the arteries. If damaged, the tiny blood vessels supplying the penis can no longer dilate to bring in the strong flow needed for a firm erection. Diabetes, high blood pressure, smoking, and high cholesterol are the major causes of both atherosclerosis and erectile dysfunction.
At the same time, low testosterone often works together with atherosclerosis to create ED. Studies show that as many as 1 in 3 men who mention ED to their doctors have low testosterone. Experts believe that if you have other factors causing erectile dysfunction, low testosterone can strongly contribute.
Strengthening the connection, low testosterone is linked in some way with many of the conditions that lead to ED:
- Metabolic syndrome, a group of conditions that together raise your risk for type 2 diabetes, heart disease, and stroke
- Endothelial dysfunction, a type of coronary artery disease
Although low testosterone isn't known to cause them, the links between other medical conditions and low testosterone can be strong.
Testosterone therapy often improves sex drive and satisfaction with sex. But the long-term risks and benefits of testosterone replacement are unknown.