Testosterone
Testosterone is the primary androgen hormone in the body, essential for muscle mass, bone density, fat distribution, red blood cell production, mood regulation, and libido. While often associated with men, testosterone plays important roles in women's health as well, including bone health, cognitive function, and energy levels.
Testosterone levels naturally decline with age — approximately 1–2% per year after age 30 in men. However, lifestyle factors like sleep quality, exercise, stress management, and body composition significantly influence testosterone levels independent of age.
Both total testosterone and free testosterone are clinically relevant. Total testosterone includes both bound (to SHBG and albumin) and unbound hormone, while free testosterone represents the bioavailable fraction that can act on tissues.
What It Measures
Total testosterone measures the total amount of testosterone circulating in the blood, including both protein-bound and free forms. It is typically reported in ng/dL for men and ng/dL or pg/mL for women.
Reference Ranges
| Status | Range (ng/dL) |
|---|---|
| Optimal | 600–900 ng/dL (men), 30–70 ng/dL (women) |
| Normal | 300–1000 ng/dL (men), 15–70 ng/dL (women) |
| Borderline | 200–300 ng/dL (men) |
| Out of Range | < 200 ng/dL (men) |
Optimal Ranges
| Group | Range | Unit | Source |
|---|---|---|---|
| Adult Men (20–49) | 264–916 | ng/dL | Standard reference |
| Adult Men (50+) | 200–750 | ng/dL | Standard reference |
| Optimal Men (functional) | 500–900 | ng/dL | Functional range |
| Adult Women | 15–70 | ng/dL | Standard reference |
When Values Are High
In men, may indicate exogenous testosterone use, adrenal tumors, or CAH. In women, elevated testosterone can indicate PCOS, adrenal hyperplasia, or ovarian tumors.
When Values Are Low
Symptoms include fatigue, low libido, erectile dysfunction, depression, muscle loss, increased body fat, and brain fog. Causes include aging, obesity, chronic stress, sleep deprivation, and certain medications.
What To Do
Lifestyle
- •Resistance training (compound lifts) acutely raises testosterone
- •Sleep 7–9 hours — testosterone is produced primarily during sleep
- •Maintain healthy body fat (15–20% for men)
- •Reduce chronic stress — cortisol suppresses testosterone
Supplements
- •Vitamin D if deficient (strongly correlated with testosterone levels)
- •Zinc 30mg/day if deficient
- •Ashwagandha (600mg/day) may modestly increase testosterone in stressed individuals
When to Retest
Retest 6–8 weeks after intervention; test in morning (levels peak 7–10 AM)
How GATOR Tracks This
Lab Providers
Related Biomarkers
This content is for informational purposes only and does not constitute medical advice. Reference ranges may vary by laboratory and individual factors. Consult a qualified healthcare provider for interpretation of your results and treatment decisions.
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