Interpretation of Your Testosterone Levels
Your total testosterone of 407 ng/dL is above the diagnostic threshold for testosterone deficiency, and you do not meet criteria for low testosterone based on current guidelines. 1
Understanding Your Results
Your testosterone levels fall into the following categories:
- Total testosterone: 407 ng/dL - This is above the 300 ng/dL threshold used by the American Urological Association to diagnose testosterone deficiency 1
- Free testosterone: 66.4 pg/mL - This is within normal range (reference range 2.5th percentile is approximately 70 pg/mL for healthy men in their 40s) 2
- Bioavailable testosterone: 148 ng/dL - This represents testosterone available for tissue uptake and is also within normal limits 3
Clinical Significance
You do not have biochemical testosterone deficiency. The diagnosis of testosterone deficiency requires BOTH of the following criteria 1:
- Two separate morning testosterone measurements below 300 ng/dL
- Presence of symptoms/signs of hypogonadism
Since your total testosterone is 407 ng/dL, you do not meet the first criterion, regardless of symptoms.
Important Context About Normal Ranges
Your testosterone level sits in the lower-middle range of normal for adult men:
- Healthy men in their 40s typically have total testosterone ranging from 251-914 ng/dL (2.5th to 97.5th percentile) 4
- The mean total testosterone for healthy men peaks at approximately 15.4 nmol/L (444 ng/dL) around age 19 and stabilizes around 13.0 nmol/L (375 ng/dL) by age 40 5
- After age 40, mean testosterone levels remain stable, though individual variation increases 5
What If You Have Symptoms?
Even though your testosterone is technically normal, if you're experiencing symptoms like reduced energy, fatigue, decreased libido, or erectile dysfunction 1, 6:
- First, ensure proper testing was done: Testosterone should be measured between 8-10 AM on two separate occasions to confirm levels 1, 6
- Consider other causes: Many conditions mimic low testosterone symptoms, including obesity, diabetes, sleep apnea, depression, thyroid disorders, and chronic medication use 6
- Lifestyle modification may help: Weight loss through calorie restriction and regular physical activity can modestly improve testosterone levels in men with borderline values 6
Common Pitfalls to Avoid
- Do not pursue testosterone replacement therapy with a level of 407 ng/dL - This would be inappropriate and potentially harmful, as you have normal testosterone levels 1
- Avoid single measurements - If concerns persist, repeat testing should be done in the early morning on a separate day 1
- Don't ignore other medical conditions - Symptoms attributed to "low T" are often caused by other treatable conditions like metabolic syndrome, depression, or medication side effects 6