Low Testosterone: 4 Things You Need to Know

Testosterone is the primary male sex hormone. It plays a key role in enabling a man's sex drive and reproductive capabilities. Testosterone levels naturally decline as men age, a condition sometimes referred to as low testosterone or low-T. When testosterone levels fall, a man may notice symptoms that include fatigue, loss of muscle and bone mass, and sexual dysfunction.

But does low-T always need to be treated in otherwise healthy middle-aged men, and what are the risks of treatment? Here are some facts about low testosterone and testosterone therapy.

1. Testosterone decline may be a normal part of aging.

Testosterone levels in otherwise healthy men have long been thought to decline over a man's lifetime, beginning around age 30. However, one recent study found that testosterone levels only decline between the ages of about 30 and 40 and then hold steady for the rest of a man's life. This new research indicates that a lot of work needs to be done simply to set baseline criteria for what constitutes low-T. Nonetheless, if your lab results indicate that your testosterone levels are low or low-normal, this could be a natural part of aging that doesn't necessarily require treatment.

2. It's unclear at what point low-T levels become medically significant.

For men born with abnormalities of the testicles or pituitary glands that cause little or no production of male sex hormones, testosterone replacement or supplementation therapy is crucial to ensure their physical development during adolescence. Testosterone therapy has also been shown to benefit some men with low-T due to HIV/AIDS.

However, for generally healthy men with declining testosterone levels later in life, there is no consensus on when the problem becomes medically relevant enough to treat. A man's sex drive, for example, seems to result from a complex interplay between testosterone and the hormone estradiol; this means that testosterone supplementation by itself for conditions like low libido may not produce a measurable result. This complexity makes it difficult to know when low testosterone is the culprit for any symptoms a man is experiencing.

3. The risks of testosterone supplementation aren't well known.

Doctors can measure a man's testosterone levels and prescribe hormone therapy to raise them, but many questions remain about the health effects of testosterone supplementation. One 2014 study found a significantly increased risk of non-fatal heart attacks in men who began testosterone therapy. However, a 2016 study showed just the opposite, and men with known coronary artery disease experienced fewer heart events after starting testosterone therapy.

Cardiovascular risk isn't the only uncertainty when it comes to testosterone therapy. It's also unclear exactly how testosterone supplementation may affect a man's risk of developing prostate cancer or breast cancer. Because more research needs to be done in order to clarify the potential risks of hormone therapy in men, you should discuss this aspect at length when consulting with a physician.

4. Men with symptoms of low testosterone should see their doctor.

Because testosterone is thought to support muscle strength and bone mass, in addition to sexual function, healthy men who are experiencing chronic fatigue, leg weakness, osteopenia, or low libido should talk to their doctor about their hormone levels and the potential benefits and risks of testosterone therapy. Testosterone requires a prescription and is usually dispensed as a patch or a topical gel. If you choose to undergo hormone therapy, be sure to follow the instructions for use very carefully, as children and women should never be exposed to testosterone gel or patches.

Hormone therapy for low testosterone may contribute to increased feelings of vitality and energy, so do not be shy about bringing up the subject with your doctor. Keep in mind, however, that this therapy requires a cautious approach as some risks remain unknown. You and your doctor should develop a personalized treatment plan for your symptoms that help you feel as healthy as possible no matter your age.