Low Testosterone

Symptoms overlap with many other conditions, so diagnosis requires proper testing — and treatment has real trade-offs, including fertility.

Symptoms are nonspecific

Low testosterone can cause reduced libido, fatigue, low mood, difficulty concentrating, loss of muscle mass, increased body fat, and reduced erectile quality.

The difficulty is that every one of those symptoms has many other explanations — depression, sleep apnea, thyroid disease, anemia, poor sleep, and simply being under strain. This is why diagnosis requires testing rather than symptoms alone, and why we look for other causes at the same time.

Testing it properly

Testosterone follows a daily rhythm and peaks in the morning, so the sample must be drawn in the morning, ideally before 10 a.m. It also varies day to day, so a diagnosis requires at least two separate low morning measurements — a single low value is not sufficient and is a common source of overdiagnosis.

Acute illness temporarily suppresses testosterone, so testing during illness is unreliable. If levels are low we also check LH, FSH, and prolactin to determine whether the problem originates in the testicles or in the pituitary, since that changes the workup.

Before reaching for treatment

Several reversible contributors are worth addressing first, because they can restore levels without any medication: untreated sleep apnea, significant obesity, excessive alcohol, chronic opioid use, and certain other medications.

Treatment and its trade-offs

Replacement is available as gels, injections, and long-acting pellets. Each has practical differences — gels can transfer to others by skin contact, injections produce peaks and troughs depending on frequency, pellets require a small office procedure a few times a year.

The most important trade-off: testosterone replacement suppresses sperm production and can cause infertility. If you may want children, say so before starting — alternative approaches such as clomiphene or hCG can raise testosterone while preserving fertility.

Treatment requires ongoing monitoring. Testosterone can raise red blood cell count to a degree that requires intervention, so we track hematocrit along with testosterone levels and PSA. Replacement is generally avoided in men with untreated prostate cancer, and used cautiously with significant cardiac disease.