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Low testosterone symptoms: common signs and when to get tested

Published 2026-11-03 · Editorial team

Medical review pending · Last updated 2026-11-03

Testosterone naturally declines with age, but a clinically low level, called hypogonadism, is a diagnosis that takes both symptoms and lab confirmation.

Common signs of low testosterone

• Lower sex drive and fewer spontaneous erections
• Erectile difficulties
• Fatigue or low energy
• Loss of muscle mass and strength; increased body fat
• Low mood, irritability, or trouble concentrating
• Reduced body hair, hot flashes, or decreased bone density

Many of these symptoms overlap with poor sleep, depression, thyroid disease, diabetes, medications, and alcohol use, which is why symptoms alone are not enough to diagnose low T.

How it is diagnosed

Clinical guidelines (Endocrine Society; American Urological Association) recommend measuring total testosterone with an early-morning blood draw, and confirming a low result with a repeat test. Providers often also check LH/FSH, a blood count (hematocrit), PSA when appropriate, and other labs to find the cause.

Common causes

Causes include testicular conditions, pituitary disorders, obesity, type 2 diabetes, opioid or steroid use, sleep apnea, and some genetic conditions.

Treatment options

If a licensed provider confirms hypogonadism, options can include lifestyle changes, treating underlying causes, and testosterone therapy (injections, gels, or other forms). Testosterone is a federally controlled substance (Schedule III), requires ongoing lab monitoring, and can reduce fertility. Learn more on our TRT page.

This article is for education only and is not medical or legal advice. A licensed clinician decides whether any treatment is appropriate for you.